Linux version 4.18

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john.ou...@gmail.com

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Jan 28, 2026, 12:04:18 AMJan 28

to cloudlab-users

I am working with a company that is considering adopting Homa, and they need to run it on an old version of Linux (4.18). Backporting Homa to 4.18 shouldn't be hard since it used to run on that release, but I need a way of testing it. Is running a 4.18 kernel on CloudLab out of the question nowadays? The alternative is for me to use VMs, which will be a bit clumsier.

-John-

David M Johnson

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Jan 28, 2026, 10:03:50 AMJan 28

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Hi John. It should still be all right to use UBUNTU20-64-STD, since
you'll just be deploying Homa. A 4.18-vintage kernel won't work on
several of the newer node types at Cloudlab Utah. One option is to grab
the latest amd64 4.18.20 stable tree test kernel packages from
https://kernel.ubuntu.com/mainline/v4.18.20/ , and download and install
manually with dpkg:

For instance on a d430:

$ wget \

https://kernel.ubuntu.com/mainline/v4.18.20/linux-headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb
\

https://kernel.ubuntu.com/mainline/v4.18.20/linux-headers-4.18.20-041820-generic_4.18.20-041820.201812030624_amd64.deb
\

https://kernel.ubuntu.com/mainline/v4.18.20/linux-image-unsigned-4.18.20-041820-generic_4.18.20-041820.201812030624_amd64.deb
\

https://kernel.ubuntu.com/mainline/v4.18.20/linux-modules-4.18.20-041820-generic_4.18.20-041820.201812030624_amd64.deb

$ dpkg -i *.deb

You might also try the Ubuntu 18 4.18 HWE kernel packages if you need
anything from the modules-extra package.

> -John-

David

John Ousterhout

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Jan 28, 2026, 11:35:52 AMJan 28

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In order to run the 4.18 version of Homa I need to have a 4.18 version of the kernel; are you saying that I could boot a 4.18 kernel on a UBUNTU20-64-STD image? I was worried that the older kernel might not provide features needed by the rest of the ecosystem on that image. Could there be similar problems if I grab 4.18.20 packages from the ubuntu Web site?

I should be able to do my testing on the xl170 cluster; I have run 4.18 kernels there in the past.

Also, what are "HWE" kernel packages?

-John-

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David M Johnson

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Jan 28, 2026, 11:56:45 AMJan 28

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On 1/28/26 09:35, John Ousterhout wrote:
> In order to run the 4.18 version of Homa I need to have a 4.18 version
> of the kernel; are you saying that I could boot a 4.18 kernel on a
> UBUNTU20-64-STD image? I was worried that the older kernel might not

Yes, that is what my instructions do; worked for me. The reason to use
Ubuntu 20 is that it has not been EOL for long and has not accumulated
significant vulnerabilities *that will affect your deployment*. (Other
deployments of Ubuntu 20 could be more exposed, so we don't generally
recommend.)

> provide features needed by the rest of the ecosystem on that image.
> Could there be similar problems if I grab 4.18.20 packages from the
> ubuntu Web site?

Some kind of kernel<->userspace ABI incompatibility (in this case of
using a newer OS release and older kernel) is possible, but I think
relatively unlikely in this case. We're only talking about 4.18 vs the
5.4 stock kernel in Ubuntu 20, and clearly the Homa module and userspace
tools support 4.18/bionic, so breakage seem unlikely. But you'll have
to try and see.

> I should be able to do my testing on the xl170 cluster; I have run 4.18
> kernels there in the past.
>
> Also, what are "HWE" kernel packages?

HWE stands for "Hardware Enablement"; see
https://wiki.ubuntu.com/Kernel/LTSEnablementStack. This provides
updated, supported Ubuntu kernels newer than the original release
kernel. E.g. Ubuntu 18 defaulted to 4.15, but then -hwe builds were
added for 4.18, 5.4, etc. You'll have to get these out of the Ubuntu
archive for the Ubuntu 18 4.18 kernels (e.g.
https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-signed-hwe/, grep
for 4.18.0-25).

> -John-

David

> On Wed, Jan 28, 2026 at 7:03 AM David M Johnson <john...@flux.utah.edu

> <mailto:john...@flux.utah.edu>> wrote:
>
> On 1/27/26 22:04, john.ou...@gmail.com <mailto:john.ou...@gmail.com>

> wrote:
> > I am working with a company that is considering adopting Homa,
> and they
> > need to run it on an old version of Linux (4.18). Backporting
> Homa to
> > 4.18 shouldn't be hard since it used to run on that release, but
> I need
> > a way of testing it. Is running a 4.18 kernel on CloudLab out of the
> > question nowadays? The alternative is for me to use VMs, which
> will be a
> > bit clumsier.
>
> Hi John. It should still be all right to use UBUNTU20-64-STD, since
> you'll just be deploying Homa. A 4.18-vintage kernel won't work on
> several of the newer node types at Cloudlab Utah. One option is to
> grab
> the latest amd64 4.18.20 stable tree test kernel packages from

> https://kernel.ubuntu.com/mainline/v4.18.20/ <https://
> kernel.ubuntu.com/mainline/v4.18.20/> , and download and install

> manually with dpkg:
>
> For instance on a d430:
>
> $ wget \
>
> https://kernel.ubuntu.com/mainline/v4.18.20/linux-

> headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb <https://
> kernel.ubuntu.com/mainline/v4.18.20/linux-
> headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb>
> \
>
> https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> headers-4.18.20-041820-generic_4.18.20-041820.201812030624_amd64.deb
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> headers-4.18.20-041820-generic_4.18.20-041820.201812030624_amd64.deb>
> \
>
> https://kernel.ubuntu.com/mainline/v4.18.20/linux-image-
> unsigned-4.18.20-041820-
> generic_4.18.20-041820.201812030624_amd64.deb <https://
> kernel.ubuntu.com/mainline/v4.18.20/linux-image-
> unsigned-4.18.20-041820-generic_4.18.20-041820.201812030624_amd64.deb>
> \
>
> https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> modules-4.18.20-041820-generic_4.18.20-041820.201812030624_amd64.deb
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> modules-4.18.20-041820-generic_4.18.20-041820.201812030624_amd64.deb>

>
> $ dpkg -i *.deb
>
> You might also try the Ubuntu 18 4.18 HWE kernel packages if you need
> anything from the modules-extra package.
>
> > -John-
>
> David
>
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John Ousterhout

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Jan 28, 2026, 12:33:01 PMJan 28

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I will give UBUNTU20-64-STD a try; thanks for all of the information!

-John-

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John Ousterhout

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Jan 30, 2026, 3:44:55 PMJan 30

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I have compiled a 4.18 kernel, installed it on the UBUNTU20-64-STD image and tried rebooting. The machine seems to reboot OK, except there are errors starting Emulab services. After the boot I can't connect to it via ssh. Any suggestions on how I can fix this?

You can see the problems in the log for node2 of this experiment:

https://www.cloudlab.us/status.php?uuid=d8628872-fca4-11f0-bc80-e4434b2381fc#

node2 is still wedged after a failed build, but you're welcome to try rebooting it if you'd like to reproduce the problem.

I'm also including an excerpt of the log that appeared in the console window (it may be more legible than what's in the full console log file):

[ OK ] Removed slice system-modprobe.slice.
[ OK ] Stopped target Host and Network Name Lookups.
[ OK ] Stopped target RPC Port Mapper.
[ OK ] Stopped target Timers.
[ OK ] Stopped Daily apt upgrade and clean activities.
[ OK ] Stopped Daily apt download activities.
[ OK ] Stopped Periodic ext4 Onli…ata Check for All Filesystems.
[ OK ] Stopped Discard unused blocks once a week.
[ OK ] Stopped Daily rotation of log files.
[ OK ] Stopped Daily man-db regeneration.
[ OK ] Stopped Message of the Day.
[ OK ] Stopped Daily Cleanup of Temporary Directories.
[ OK ] Closed LVM2 poll daemon socket.
[ OK ] Closed Load/Save RF Kill Switch Status /dev/rfkill Watch.
Unmounting RPC Pipe File System...
Stopping Availability of block devices...
Stopping Create final runt…dir for shutdown pivot root...
Stopping Authorization Manager...
Stopping Load/Save Random Seed...
[ OK ] Stopped target Login Prompts.
Stopping Accounts Service...
Stopping Regular background program processing daemon...
Stopping D-Bus System Message Bus...
Stopping Getty on tty1...
Stopping LSB: Record successful boot for GRUB...
Stopping LSB: Load kernel image with kexec...
Stopping Dispatcher daemon for systemd-networkd...
Stopping Network Time Service...
Stopping Syste Stopping Serial Getty on ttyS0...
Stopping Self Monitoring a…g Technology (SMART) Daemon...
Stopping OpenBSD Secure Shell server...
Stopping Login Service...
[ OK ] Stopped Accounts Service.
[ OK ] Stopped Dispatcher daemon for systemd-networkd.
[ OK ] Stopped System Logging Service.
[ OK ] Stopped Self Monitoring an…ing Technology (SMART) Daemon.
[ OK ] Stopped Login Service.
[ OK ] Stopped Authorization Manager.
[ OK ] Stopped Regular background program processing daemon.
[ OK ] Stopped Testbed Services.
[ OK ] Stopped Network Time Service.
[ OK ] Stopped Serial Getty on ttyS0.
[ OK ] Stopped OpenBSD Secure Shell server.
[ OK ] Stopped Getty on tty1.
[ OK ] Unmounted RPC Pipe File System.
[ OK ] Stopped Availability of block devices.
[ OK ] Stopped Load/Save Random Seed.
[ OK ] Stopped D-Bus System Message Bus.
[ OK ] Stopped LSB: Record successful boot for GRUB.
[ OK ] Removed slice system-getty.slice.
[ OK ] Removed slice system-serial\x2dgetty.slice.
[ OK ] Stopped target Network is Online.
Stopping Permit User Sessions...
[ OK ] Stopped Create final runtime dir for shutdown pivot root.
[ OK ] Stopped LSB: Load kernel image with kexec.
[ OK ] Stopped Permit User Sessions.
[ OK ] Stopped target Network.
[ OK ] Stopped target User and Group Name Lookups.
[ OK ] Stopped target Remote File Systems.
[ OK ] Stopped target Remote File Systems (Pre).
[ OK ] Stopped target NFS client services.
Stopping LSB: Execute the …-e command to reboot system...
Stopping Network Name Resolution...
[ OK ] Stopped Network Name Resolution.
[ OK ] Stopped LSB: Execute the k…c -e command to reboot system.
[ OK ] Stopped target Basic System.
[ OK ] Stopped target Paths.
[ OK ] Stopped target Slices.
[ OK ] Removed slice User and Session Slice.
[ OK ] Stopped target Sockets.
[ OK ] Closed D-Bus System Message Bus Socket.
[ OK ] Closed Open-iSCSI iscsid Socket.
[ OK ] Closed Syslog Socket.
[ OK ] Closed UUID daemon activation socket.
[ OK ] Stopped target System Initialization.
[ OK ] Stopped target Local Encrypted Volumes.
[ OK ] Stopped Dispatch Password …ts to Console Directory Watch.
[ OK ] Stopped Forward Password R…uests to Wall Directory Watch.
[ OK ] Stopped target Swap.
Deactivating swap /dev/dis…TOSHIBA__563S10G3TUFV-part3part3.
[ OK ] Deactivated swap /dev/nvme0n1p3.
[ OK ] Deactivated swap /dev/disk…5-ab25-48d6-984b-7f7690358c28.
[ OK ] Stopped Update UTMP about System Boot/[ OK ] Stopped Monitoring of LVM2… dmeventd or progress polling.
[ OK ] Reached target Shutdown.
[ OK ] Reached target Final Step.
[ OK ] Finish[ 224.769410] reboot: Power down
HP ProLiant System BIOS H05 v1.00 (05/09/2016)
(C) Copyright 1982 - 2016 Hewlett Packard Enterprise Development LP
(C) Copyright 1982 - 2016 Hewlett Packard Enterprise Development LP
HP ProLiant m510 Server Cartridge
BIOS Version: H05 v1.00 (05/09/2016)
Serial Number: CN7626V15R
Booting `Ubuntu'

[ 0.000000] microcode: microcode updated early to revision 0x700001c, date = 2021-06-12
[ 0.000000] Linux version 4.18.0+ (ous...@node0.ouster-287877.homa-pg0.utah.cloudlab.us) (gcc version 9.4.0 (Ubuntu 9.4.0-1ubunt
u1~20.04.2)) #5 SMP Fri Jan 30 12:53:17 MST 2026
[ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.18.0+ root=UUID=8b9e1980-828f-418f-ae44-80689ca8bd2f ro console=ttyS0,11520
0 emulabcnet=ec:b1:d7:85:3a:12
[ 0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
[ 0.000000] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
[ 0.000000] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
[ 0.000000] x86/fpu: xstate_offset[2]: 576, xstate_sizes[2]: 256
[ 0.000000] x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'standard' format.
[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x0000000000092fff] usable
[ 0.000000] BIOS-e820: [mem 0x0000000000093000-0x0000000000093fff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000000094000-0x000000000009ffff] usable
[ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000006b3a0fff] usable
[ 0.000000] BIOS-e820: [mem 0x000000006b3a1000-0x000000006b9a0fff] reserved
[ 0.000000] BIOS-e820: [mem 0x000000006b9a1000-0x000000006b9a1fff] usable
[ 0.000000] BIOS-e820: [mem 0x000000006b9a2000-0x000000006ba22fff] reserved
[ 0.000000] BIOS-e820: [mem 0x000000006ba23000-0x00000000784fefff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000784ff000-0x00000000788fefff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000788ff000-0x00000000790fefff] type 20
[ 0.000000] BIOS-e820: [mem 0x00000000790ff000-0x00000000791fefff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000791ff000-0x000000007b5fefff] ACPI NVS
[ 0.000000] BIOS-e820: [mem 0x000000007b5ff000-0x000000007b7fefff] ACPI data
[ 0.000000] BIOS-e820: [mem 0x000000007b7ff000-0x000000007b7fffff] usable
[ 0.000000] BIOS-e820: [mem 0x000000008000x000000008fffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000107fffffff] usable
[ 0.000000] NX (Execute Disable) protection: active
[ 0.000000] efi: EFI v2.40 by HP
[ 0.000000] efi: ACPI=0x7b7fe000 ACPI 2.0=0x7b7fe014 SMBIOS=0x788da000
[ 0.000000] SMBIOS 2.8 present.
[ 0.000000] DMI: HP ProLiant m510 Server Cartridge/ProLiant m510 Server Cartridge, BIOS H05 05/09/2016
[ 0.000000] last_pfn = 0x1080000 max_arch_pfn = 0x400000000
[ 0.000000] x86/PAT: Configuration [0-7]: WB WC UC- UC WB WP UC- WT
[ 0.000000] last_pfn = 0x7b800 max_arch_pfn = 0x400000000
[ 0.000000] Scanning 1 areas for low memory corruption
[ 0.000000] Using GB pages for direct mapping
[ 0.000000] Secure boot could not be determined
[ 0.000000] RAMDISK: [mem 0x35803000-0x36bf8fff]
[ 0.000000] ACPI: Early table checksum verification disabled
[ 0.000000] ACPI: RSDP 0x000000007B7FE014 000024 (v02 HP )
[ 0.000000] ACPI: XSDT 0x000000007B7E8188 0000F4v01 HP ProLiant 00000001 01000013)
[ 0.000000] ACPI: FACP 0x000000007B7F5000 00010C (v05 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: DSDT 0x000000007B7E2000 004EB5 (v02 HP DSDT 00000002 HPAG 00020000)
[ 0.000000] ACPI: FACS 0x000000007B581000 000040
[ 0.000000] ACPI: UEFI 0x000000007B5B9000 000042 (v01 HP ProLiant 00000002 01000013)
[ 0.000000] ACPI: MCEJ 0x000000007B7FC000 000130 (v01 HP ProLiant 00000001 INTL 0100000D)
[ 0.000000] ACPI: SSDT 0x000000007B7FB000 000064 (v02 HP SpsNvs 00000002 INTL 20130328)
[ 0.000000] ACPI: HEST 0x000000007B7FA000 0000A8 (v01 HP ProLiant 00000001 INTL 00000001)
[ 0.000000] ACPI: BERT 0x000000007B7F9000 000030 (v01 HP ProLiant 00000001 INTL 00000001)
[ 0.000000] ACPI: ERST 0x000000007B7F8000 000230 (v01 HP ProLiant 00000001 INTL 00000001)
[ 0.000000] ACPI: EINJ 0x000000007B7F7000 000150 (v01 HP ProLiant 00000001 INTL 00000001)
[ 0.000000] ACPI: BGRT 0x000000007B7F6000038 (v01 HP ProLiant 00000002 HP 01000013)
[ 0.000000] ACPI: HPET 0x000000007B7F4000 000038 (v01 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: PMCT 0x000000007B7F3000 000064 (v01 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: WDDT 0x000000007B7F2000 000040 (v01 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: APIC 0x000000007B7F1000 00021E (v03 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: MCFG 0x000000007B7F0000 00003C (v01 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: SLIT 0x000000007B7EF000 00002D (v01 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: SRAT 0x000000007B7EE000 0001D8 (v03 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: SPMI 0x000000007B7ED000 000041 (v05 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: RASF 0x000000007B7EC000 000030 (v01 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: SPCR 0x000000007B7EB000 000050 (v01 HP ProLiant 00000001 HP 000001)
[ 0.000000] ACPI: MSCT 0x000000007B7EA000 00004E (v01 HP ProLiant 00000001 HP 00000001)
[ 0.000000] ACPI: BDAT 0x000000007B7E9000 000030 (v01 HP ProLiant 0A PXM 0 -> APIC 0x000c -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x000e -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x0001 -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x0003 -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x0005 -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x0007 -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x0009 -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x000b -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x000d -> Node 0
[ 0.000000] SRAT: PXM 0 -> APIC 0x000f -> Node 0
[ 0.000000] ACPI: SRAT: Node 0 PXM 0 [mem 0x00000000-0x107fffffff]
[ 0.000000] NODE_DATA(0) allocated [mem 0x107fffb000-0x107fffefff]
[ 0.000000] tsc: Fast TSC calibration using PIT
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000000001000-0x0000000000ffffff]
[ 0.000000] DMA32 [mem 0x0000000001000000-0x00000000ffffffff]
[ 0.000000] Normal [mem 0x0000000100000000-0x000000107fffffff]
[ 0.000000c nored
[ 0.000000] ACPI: x2apic entry ignored
[ 0.000000] ACPI: x2apic entry ignored
[ 0.000000] ACPI: x2apic entry ignored
[ 0.000000] ACPI: x2apic entry ignored
[ 0.000000] ACPI: x2apic entry ignored
[ 0.000000] A Unexpected SPCR Access Width. Defaulting to byte size
[ .0000] ACPI: SPCR: console: uart,mmio,0x0,115200
[ 0.000000] smpboot: Boot CPU (id 0) not listed by BIOS
[ 0.000000] smpboot: Allowing 1 CPUs, 0 hotplug CPUs
[ 0.00000em 0x80000000-0x8fffffff]
[ 0.000000] PM: Registered nosave memory: [mem 0x90000000-0xffffffff]
[ 0.000000] [mem 0x90000000-0xffffffff] available for PCI devices
[ 0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cyc]LUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.000000] Kernel/User page tables isolation: enabled
[ 0.000000] Hierarchical RCU implementation.
[ 0.000000] RCU event tracing is enabled.
[ 0.000000] RCU restricting CPUs from NR_CPUS=64 to nr_cpu_ids=1.
[ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[ 0.000000] NR_IRQS: 4352, nr_irqs: 256, preallocated irqs: 16
[ 0.000000] Console: colour dummy device 80x25
[ 0.000000] console [ttyS0] enabled
[ 0.000000] ACPI: Core revision 20180531
[ 0.000000] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 133484882848 ns
[ 0.000000] APIC: Switch to symmetric I/O mode 0.009004] Calibrating delay loop (skipped), value calculated using timer frequency.. 3990.77 BogoMIPS (lpj=1995388)
[ 0.010003] pid_max: default: 32768 minimum: 301
[ 0.012034] Security Framework initialized
[ 0.013005] SELinu[ 0.048339] CPU: Physical Processor ID: 0
[ 0.049002] CPU: Processor Core ID: 0
[ 0.050018] mce: CPU supports 22 MCE banks
[ 0.051030] CPU0: Thermal monitoring enabled (TM1)
[ 0.052039] process: using mwait in idle thread113003] ... event mask: 000000070000000f
[ 0.114069] Hierarchical SRCU implementation.
[ 0.115212] smp: Bringing up secondary CPUs ...
[ 0.116004] smp: Brought up 1 node, 1 CPU
[ 0.117003] smpboot: Max logical pa[ 0.130204] audit: initializing netlink subsys (disabled)
[ 0.131091] kworker/u2:0 (17) used greatest stack depth: 14704 bytes left
[ 0.132280] cpuidle: using governor menu
[ 0.133152] Detected 1 PCC Subspaces
[ 0.134081]78013] ACPI: (supports S0 S5)
[ 0.179001] ACPI: Using IOAPIC for interrupt routing
[ 0.180030] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug
[ 0.181046] ACPI: Enabled 10 GPEs in block 0io logical cpu number
[ 0.202077] APIC: NR_CPUS/possible_cpus limit of 1 reached. Processor 4/0x4 ignored.
[ 0.203002] ACPI: Unable to map lapic to logical cpu number
[ 0.204029] APIC: NR_CPUS/possible_cpus limit of 1 reached. Processor 5/0x5 ignored.
[ 0.205004] ACPI: Unable to map lapic to logical cpu number
[ 0.206056] APIC: NR_CPUS/possible_cpus limit of 1 reached. Processor 6/0x6 ignored.
[ 0.207002] ACPI: Unable to map lapic to logical cpu number
[ 0.208028] APIC: NR_CPUS/possible_cpus limit of 1 reached. Processor 7/0x7 ignored.
[ 0.209002] ACPI: Unable to map lapic to logical cpu number
[ 0.210048] APIC: NR_CPUS/possible_cpus limit of 1 reached. Processor 8/0x8 ignoreed.
[ 0.215002] ACPI: Unable to map lapic to logical cpu number
[ 0.216032] APIC: NR_CPUS/possible_cpus limit of 1 reached. Processor 11/0xb ignored.
[ 0.217002] ACPI: Unable to map lapic to logical cpu number
[ 0.218048] APP_: platform does not support [AER LTR]
[ 0.229099] acpi PNP0A08:00: _OSC: OS now controls [PME PCIeCapability]
[ 0.230003] acpi PNP0A08:00: FADT indicates ASPM is unsupported, using BIOS configuration
[ 0.231226] PCI host bridg root bus resource [bus 00-fe]
[ 0.242242] pci 0000:00:01.0: enabling Extended Tags
[ 0.243711] pci 0000:00:02.2: enabling Extended Tags
[ 0.244355] pci 0000:00:03.0: enabling Extended Tags
[ 0.245179] pci 0000:00:03.1: enab.6: PCI bridge to [bus 04]
[ 0.265527] pci 0000:01:00.1: BAR 0: assigned to efifb
[ 0.269046] pci 0000:00:1c.7: PCI bridge to [bus 01]
[ 0.270254] ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 6 7 9 10 11 12 14 15) *0, disabled.
[ 0.278370] pci 0000:01:00.1: vgaarb: setting as boot VGA device
[ 0.279000] pci 0000:01:00.1: vgaarb: VGA device added: decodes=io+mem,owns=io+mem,locks=none
[ 0.279003] pci 0000:01:00.1: vgaarb: bridge control possible
[ 0.= 128
[ 0.311001] NetLabel: protocols = UNLABELED CIPSOv4 CALIPSO
[ 0.312046] NetLabel: unlabeled traclowed by default
[ 0.314628] hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0, 0, 0, 0, 0, 0
[ 0.315006] hpet0: 8 comparators, 64-bit 14.318180 MHz counter
[ 0.318050] clocksource: Switched to clocksource tsc-early
[ 0.328017] VFS: Disk quotas dquot_6.6.0
[ 0.329226] VFS: Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
[ 0.331405] pnp: PnP ACPI init
[ 0.332698] system 00:01: [io 0x0500-0x053f] has been reserved
[ 0.334522] system 00:01: [io 0x0400-0x047f] has been reserved
[ 0.336310] system 00:01: [io 0x0540-0x057f] has been reserved
[ 0.338130] system 00:01: [io 0x0600-0x061f] has been reserved
[ 0.339945] system 00:01: [io 0x0880-0x0883] has been reserved
[ 0.341779] system 00:01: [io 0x0800-0x081f] has been reserved
[ 0.343574] system 00:01: [mem 0xfed1c000-0xfed3ffff] has b00:00:02.0: PCI bridge to [bus 05]
[ 0.582181] pci 0000:00:02.0: bridge window [mem 0x93a00000-0x93afffff]39] pci 0000:00:02.1: PCI bridge to [bus 06]
[ 0.985708] pci 0000:00:02.2: PCI bridge to [bus 07]
[ 0.987266] pci 0000:00:02.3: PCI bridge to [bus 08]
[ 0.988790] pci 0000:00:03.0: PCI bridge to [bus 0b]
[ 0.990404] pci 0000:00:03.1: PCI bridge to [bus 0c]
[ 0.991925] pci 0000:00:03.2: PCI bridge to [bus 0d]
[ 0.993424] pci 0000:00:03.2: br:01:00.4: quirk_usb_early_handoff+0x0/0x67f took 134 usecs
[ 1.242569] Unpacking initramfs...
[ 1.417904] Freeing initrd memory: 20440K
[ 1.419484] DMAR: Host address width 46
[ 1.420711] DMAR: DRHD base: 0x000000fbffc000 flags: 0x1
[ 1.422370] DMAR: dmar0: reg_base_addr fbffc000 ver 1:0 cap 8d2078c106f0466 ecap f020de
[ 1.424747] DMAR: RMRR base: 0x0000007916d000 end: 0x0000007916ffff
[ 1.426701] DMAR: RMRR base: 0x000000791ed000 end: 0x000000791f0fff
[ 1.428678] DMAR: RMRR base: 0x000000791d7000 end: 0x000000791ecfff
[ 1.430668] DMAR: RMRR base: 0x000000791c4000 end: 0x000000791d4fff
[ 1.432578] DMAR: RMRR base: 0x000000791d5000 end: 0x000000791d6fff
[ 1.434473] DMAI INT A: not connected
[ 1.680231] pcieport 0:00:1c.4: can't derive routing for PCI INT A
[ 1.782228] pcieport 0000:00:1c.4: PCI INT A: not connected
[ 1.784160] pcieport 0000:00:1c.6: can't derive routing for PCI INT C
[ 1.786132] pcieport 0000:00:1c.6: PCI INT C: not connected
[ 1.788043] pcieport 0000:00:01.0: Signaling PME with IRQ 25
[ 1.789841] pcieport 0000:00:01.1: Signaling PME with IRQ 26
[ 1.791598] pcieport 0000:00:02.0: Signaling PME with IRQ 28
[ 1.793441] pcieport 0000:00:02.1: Signaling PME with IRQ 29
[ 1.795196] pcieport 0000:00:02.2: Signaling PME with IRQ 30
[ 1.796940] pcieport 0000:00:02.3: Signaling PME with IRQ 31
[ 1.798692] pcieport 0000:00:0] pcieport 0000:00:1c.4: Signaling PME with IRQ1.942135] pcieport 0000:00:1c.6: Signaling PME with IRQ 39
[ 2.111403] pcieport 0000:00:1c.7: Signaling PME with IRQ 40
[ 2.113192] efifb: probing for efifb
[ 2.114304] efifb: framebuffer at 0x91000000, using 3072k, total 3072k
[ 2.116267] efifb: mode is 1024x768x32, linelength=4096, pages=1
[ 2.118093] efifb: scrolling: redraw
[ 2.119181] efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0
[ 2.153643] Con18
[ 2.460365] usb usb1: New USB device strs: Mfr=3, Product=2, SerialNumber=1
[ 2.562577] usb usb1: Product: EHCI Host Controller
[ 2.564125] usb usb1: Manufacturer: Linux 4.18.0+ ehci_hcd
[ 2.565824] usb usb1: SerialNumberb usb2: Product: UHCI Host Controller
[ 2.689705] usb usb2: Manufacturer: Linux 4.18.0+ uhci_hcd
[ 2.691481] usb usb2: SerialNumber: 0000:01:00.4
[ 2.692991] hub 2-0:1.0: USB hub found
[ 2.694277] hub 2-0:1.0: 2 ports detect[ 3.220671] i8042: Can't read CTR while initializing i8042
[ 3.222480] i8042: probe of i8042 failed with error -5
[ 3.224309] rtc_cmos 00:00: RTC can wake from S4
[ 3.226071] rtc_cmos 00:00: registered as rtc0
[ 3.227554] rtc_cmos 00:00: alarms up to one month, y3k, 114 bytes nvram, hpet irqs
[ 3.230244] i801_smbus 0000:00:1f.3: enabling device (0000 -> 0003)
[ 3.232416] i801_smbus 0000:00:1f.3: SMBus using PCI interrupt
[ 3.234802] device-mapper: ioctl: 4.39.0-ioctl (2018-04-03) initialised: dm-d...@redhat.com
[ 3.237626] intel_pstate: Intel P-state driver initializing
[ 3.239461] EFI Variables Facility v0.08 2004-May-17
[ 3.261803] hidraw: raw HID events driver (C) Jiri Kosina
[ 3.264193] usbcore: registered new interface driver usbhid
[ 3.266071] usbhid: USB HID core driver
[ 3.267908] Initializing XFRM netlink socket
[ 3.269545] NET: Registered protocol family 10
[ 3.271315] Segm3.290145] console [netcon0] enabled
[ 3.291362] netconsole: network logging started
[ 3.292919] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[ 3.297649] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf[ 3.708585] Freeing unused kernel memory: 1252K
[ 3.730256] tsc: Refined TSC clocksource calibration: 1995.377 MHz
[ 3.757975] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x39863ddfe0b, max_idle_ns: 881590582559 ns
[ 3.803099] usb 1-1: new high-speed USB device number 2 using ehci-pci
[ 3.832389] Write protecting the kernel read-only data: 18432k
[ 3.859496] Freeing unused kernel memory: 2004K
[ 3.881780] Freeing unused kernel memory: 108[ 4.030845] random: fast init done
Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... ln: /tmp/mountroot-fail-hooks.d//scripts/init-premount/lvm2: No such file or directory
done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done.
Begin: Running /scripts/local-premount ... done.
Begin: Will now check root file system ... fsck from util-linux 2.34
[/usr/sbin/fsck.ext3 (1) -- /dev/nvme0n1p1] fsck.ext3 -a -C0 /dev/nvme0n1p1
/dev/nvme0n1p1: clean, 123311/1048576 files, 752694/4194304 blocks
done.
[ 4.983557] EXT4-fs (nvme0n1p1): mounting ext3 file system using the ext4 subsystem
[ 5.022813] EXT4-fs (nvme0n1p1): mounted filesystem with ordered data mode. Opts: (null)
done.
Begin: Running /scripts/local-bottom ... done.
Begin: Running /scripts/init-bottom ... [ 5.077462] systemd-udevd (1343) used greatest stack depth: 14008 bytes left
[ 5.112479] systemd-udevd (1348) used greatest stack depth: 13976 bytes left
done.
SELinux: Could not open policy file <= /etc/selinux/targeted/policy/policy.32: No such file or directory
[ 5.223166] modprobe (1419) used greatest stack depth: 13056 bytes left
[ 5.298806] systemd[1]: systemd 245.4-4ubuntu3.20 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default-hierarchy=hybrid)
[ 5.413111] systemd[1]: Detected architecture x86-64.

Welcome to Ubuntu 20.04 LTS!

[ 5.440267] systemd[1]: Set hostname to <localhost>.
[ 5.539783] openvpn-generat (1424) used greatest stack depth: 13040 bytes left
[ 5.587328] random: lvmconfig: uninitialized urandom read (4 bytes read)
[ 5.663857] systemd[1]: Configuration file /run/systemd/system/netplan-ovs-cleanup.service is marked world-inaccessible. This has no effect as configuration data is accessible via APIs without restrictions. Proceeding anyway.
[ 5.772317] systemd[1]: /etc/systemd/system/pubsubd.service:11: PIDFile= references a path below legacy directory /var/run/, updating /var/run/pubsubd.pid → /run/pubsubd.pid; please update the unit file accordingly.
[ 5.895570] systemd[1]: system-modprobe.slice: unit configures an IP firewall, but the local system does not support BPF/cgroup firewalling.
[ 5.955518] systemd[1]: (This warning is only shown for the first unit using IP firewalling.)
[ 5.996448] systemd[1]: Created slice system-modprobe.slice.
[ OK ] Created slice system-modprobe.slice.
[ 6.026251] systemd[1]: Created slice system-serial\x2dgetty.slice.
[ OK ] Created slice system-serial\x2dgetty.slice.
[ 6.057185] systemd[1]: Created slice User and Session Slice.
[ OK ] Created slice User and Session Slice.
[ 6.086162] systemd[1]: Started Dispatch Password Requests to Console Directory Watch.
[ OK ] Started Dispatch Password …ts to Console Directory Watch.
[ 6.125141] systemd[1]: Started Forward Password Requests to Wall Directory Watch.
[ OK ] Started Forward Password R…uests to Wall Directory Watch.
[ 6.162563] systemd[1]: Set up automount Arbitrary Executable File Formats File System Automount Point.
[ OK ] Set up automount Arbitrary…s File System Automount Point.
[ 6.207068] systemd[1]: Reached target Local Encrypted Volumes.
[ OK ] Reached target Local Encrypted Volumes.
[ 6.237094] systemd[1]: Reached target User and Group Name Lookups.
[ OK ] Reached target User and Group Name Lookups.
[ 6.268055] systemd[1]: Reached target Paths.
[ OK ] Reached tar.
[ OK ] Listening on RPCbind Server Activation Socket.
[ 6.407156] systemd[1]: Listening on Syslog Socket.
[ OK ] Listening on Syslog Socket.
[ 6.432134] systemd[1]: Listening o Journal Socket (/dev/log).
[ OK ] Listening on Journal Socket (/dev/log).
[ 6.555166] systemd[1]: Listening on Journal Socket.
[ OK ] Listening on Journal Socket.
[ 6.582177] sy Socket.
[ OK ] Listening on udev Control Socket.
[ 6.610189] systemd[1]: Listening on udev Kernel Socket.
[ OK ] Listening on udev Kernel Socket.
[ 6.638000] systemd[1]: Mountin6.903076] systemd[1]: Condition check resulted in Create list of static device nodes for the current kernel being skipped.
[ 7.066486] systemd[1]: Starting Monitoring of LVM2 mirrors, snapshots etc. using dmeventd or progress polling...
[ 7.128819] random: lvm: uninitialized urandom read (4 bytes read)
Starting Monitoring of LVM…meventd or progress polling...
[ 7.228596] systemd[1]: Starting Load Kernel Module chromeos_pstore...
Starting Load Kernel Module chromeos_pstore...
[ 7.289062] systemd[1]: Condition check resulted in Load Kernel Module drm being skipped.
[ 7.327263] systemd[1]: Starting Load Kernel Module efi_pstore...
Starting Load Kernel Module efi_pstore...
[ 7.359728] systemd[1]: Starting Load Kernel Module pstore_blk...
Starting Load Kernel Module pstore_blk...
[ 7.392740] systemd[1]: Starting Load Kernel Module pstore_zone...
Starting Load Kernel Module pstore_zone...
[ 7.425824] systemd[1]: Starting Load Kernel Module ramoops...
Starting Load Kernel Module ramoops...
[ 7.457120] systemd[1]: Core-mounted. Opts: errors=remount-ro
[ 7.713219] systemd[1]: Started Journal Service.
[ OK ] Started Journal Service.
[ OK ] Mounted Huge Pages File System.
[ OK ] Mount Starting Apply Kernel Variables...
Starting Create System Users...
[ 7.819176] systemd-journald[1449]: Received client request to flush runtime journal.
[ OK ] Finished inished Enable support fo…nal executable binary formats.
[ OK ] Started udev Kernel Device Manager.
[ OK ] Finished udev Coldplug all Devices.
[ OK ] Finished Flush Journal to Persistent Storage.
Starting Create Volatile Files and Directories...
[ OK ] Finished Create Volatile Files and Directories.
Starting RPC bind portmap service...
Starting Update UTMP about System Boot/Shutdown...
[ OK ] Started RPC bind portmap service.
[ OK ] Reached target RPC Port Mapper.
[ OK ] Finished Update UTMP about System Boot/Shutdown.
[ OK ] Found device /dev/ttyS0.
[ OK ] Found device THNSN5256GPU7 TOSHIBA 3.
[ OK ] Listening on Load/Save RF …itch Status /dev/rfkill Watch.
Activating swap /dev/disk/…ab25-48d6-984b-7f7690358c28...
[ OK ] Activated swap /dev/disk/b…5-ab25-48d6-984b-7f7690358c28.
[ OK ] Reached target Swap.
[ OK ] Reached target System Initialization.
[ OK ] Started Daily apt download activities.
[ OK ] Started [ OK ] Started Daily Cleanup of Temporary Directories.
[ OK ] Reached target Timers.
[ OK ] Listening on D-Bus System Message Bus Socket.
[ OK ] L Starting Remove Stale Onli…t4 Metadata Check Snapshots...
Starting Emulab fstab fixup (swap)...
Starting LSB: Record successful boot for GRUB...
[ OK ] Star;1;39mLSB: Record successful boot for GRUB.
Starting GRUB failed boot detection...
[ OK ] Started Self Monitoring an…ing Technology (SMART) Daemon.
etadata Check Snapshots.
[ OK ] Started Dispatcher daemon for systemd-networkd.
[ OK ] Finished Load/Save Random Seed.
[FAILED] Failed to start Force udev…efore systemd-networkd starts.
See 'systemctl status emulab-udev-settle-networkd.service' for details.
[DEPEND] Dependency failed for Network Service.
[DEPEND] Dependency failed for Wait for Network to be Configured.
Starting Network Name Resolution...
[ OK ] Started Network Name Resolution.
[ OK ] Reached target Network.
[ OK ] Reached target Network is Online.
[ OK ] Reached target Host and Network Name Lookups.
Starting Network Time Service...
[ OK ] Reached target Remote File Systems (Pre).
[ OK ] Reached target Remote File Systems.
Starting Availability of block devices...
[ OK ] Started Regular background program processing daemon.
Starting LSB: Load kernel image with kexec...
Starting The Emulab publish/subscribe daemon...
Starting OpenBSD Secure Shell server...
Starting Permit User Sessions...
Starting Testbed Services...
[ OK ] Started Network Time Service.
[ OK ] Finished Availability of block devices.
[FAILED] Failed to start The Emulab publish/subscribe daemon.
See 'systemctl status pubsubd.service' for details.
[ 128.554561] sh[1984]: testbed config:
[ 128.555244] sh[2009]: Checking manifest...

David M Johnson

unread,

Jan 30, 2026, 4:01:27 PMJan 30

to cloudla...@googlegroups.com

On 1/30/26 13:44, John Ousterhout wrote:
> I have compiled a 4.18 kernel, installed it on the UBUNTU20-64-STD image
> and tried rebooting. The machine seems to reboot OK, except there are
> errors starting Emulab services. After the boot I can't connect to it
> via ssh. Any suggestions on how I can fix this?

It looks like your build does not include the required mlx4_en driver
for the m510s, so the public control net interface did not get an
address via DHCP. You can see driver/firmware requirements for a node
type by running `sudo lshw -c net` on one of your up machines, then
check your build for the module `sudo modinfo mlx4_en`. Oftentimes we
suggest you start your custom build from the default Ubuntu
/boot/config-* kernel config (as in
https://groups.google.com/g/cloudlab-users/c/y3SwBbUs2oE/m/M67jRhFSAAAJ).
Or, here are the specific config bits you would lift from a stock
Ubuntu config:

CONFIG_MLX4_EN=m
CONFIG_MLX4_EN_DCB=y
CONFIG_MLX4_CORE=m
CONFIG_MLX4_DEBUG=y
CONFIG_MLX4_CORE_GEN2=y

David

> You can see the problems in the log for node2 of this experiment:
>
> https://www.cloudlab.us/status.php?uuid=d8628872-fca4-11f0-bc80-

> e4434b2381fc# <https://www.cloudlab.us/status.php?uuid=d8628872-
> fca4-11f0-bc80-e4434b2381fc#>

> pg0.utah.cloudlab.us <mailto:ous...@node0.ouster-287877.homa-
> pg0.utah.cloudlab.us>) (gcc version 9.4.0 (Ubuntu 9.4.0-1ubunt

> initialised: dm-d...@redhat.com <mailto:dm-d...@redhat.com>

> https://wiki.ubuntu.com/Kernel/LTSEnablementStack <https://
> wiki.ubuntu.com/Kernel/LTSEnablementStack>. This provides

> updated, supported Ubuntu kernels newer than the original release
> kernel. E.g. Ubuntu 18 defaulted to 4.15, but then -hwe builds
> were
> added for 4.18, 5.4, etc. You'll have to get these out of the
> Ubuntu
> archive for the Ubuntu 18 4.18 kernels (e.g.
> https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-signed-

> hwe/ <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-
> signed-hwe/>, grep

> for 4.18.0-25).
>
> > -John-
>
> David
>
> > On Wed, Jan 28, 2026 at 7:03 AM David M Johnson
> <john...@flux.utah.edu <mailto:john...@flux.utah.edu>

> > <mailto:john...@flux.utah.edu

> <mailto:john...@flux.utah.edu>>> wrote:
> >
> > On 1/27/26 22:04, john.ou...@gmail.com

> <mailto:john.ou...@gmail.com> <mailto:john.ou...@gmail.com

> kernel.ubuntu.com/mainline/v4.18.20/> <https://
> > kernel.ubuntu.com/mainline/v4.18.20/ <http://

> kernel.ubuntu.com/mainline/v4.18.20/>> , and download and install
> > manually with dpkg:
> >
> > For instance on a d430:
> >
> > $ wget \
> >

> > https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://
> kernel.ubuntu.com/mainline/v4.18.20/linux->
> >
> headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb
> <https://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->
> > headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb>
> > \
> >
> > https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://
> kernel.ubuntu.com/mainline/v4.18.20/linux->
> > headers-4.18.20-041820-
> generic_4.18.20-041820.201812030624_amd64.deb
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > headers-4.18.20-041820-
> generic_4.18.20-041820.201812030624_amd64.deb>
> > \
> >
> > https://kernel.ubuntu.com/mainline/v4.18.20/linux-image-

> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->
> > unsigned-4.18.20-041820-
> > generic_4.18.20-041820.201812030624_amd64.deb <https://

> > kernel.ubuntu.com/mainline/v4.18.20/linux-image- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-image->
> > unsigned-4.18.20-041820-
> generic_4.18.20-041820.201812030624_amd64.deb>
> > \
> >
> > https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://
> kernel.ubuntu.com/mainline/v4.18.20/linux->
> > modules-4.18.20-041820-
> generic_4.18.20-041820.201812030624_amd64.deb
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > modules-4.18.20-041820-

> generic_4.18.20-041820.201812030624_amd64.deb>
> >
> > $ dpkg -i *.deb
> >
> > You might also try the Ubuntu 18 4.18 HWE kernel packages
> if you need
> > anything from the modules-extra package.
> >
> > > -John-
> >
> > David
> >
> > --
> > You received this message because you are subscribed to
> the Google
> > Groups "cloudlab-users" group.
> > To unsubscribe from this group and stop receiving emails
> from it,
> > send an email to cloudlab-

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> users%2Bunsu...@googlegroups.com>
> > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>>.

> > To view this discussion visit https://groups.google.com/

> d/msgid/ <https://groups.google.com/d/msgid/>
> > cloudlab-users/f8a2e6b3-65bf-4646-ab10-
> ccf8ae7c05cb%40flux.utah.edu <http://40flux.utah.edu>
> > <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/>
> > f8a2e6b3-65bf-4646-ab10-ccf8ae7c05cb%40flux.utah.edu
> <http://40flux.utah.edu>>.

> >
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> <mailto:cloudlab-users%2Bunsu...@googlegroups.com>>.
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> > cloudlab-users/
> >
> CAGXJAmxEc25HWU%3DnSc5F0Aq7sdJC%3D1d3k6Ku2GrPN4cTt7CFcw%40mail.gmail.com <http://40mail.gmail.com>
> > <https://groups.google.com/d/msgid/cloudlab-users/ <https://
> groups.google.com/d/msgid/cloudlab-users/>
> >
> CAGXJAmxEc25HWU%3DnSc5F0Aq7sdJC%3D1d3k6Ku2GrPN4cTt7CFcw%40mail.gmail.com?utm_medium=email&utm_source=footer <http://40mail.gmail.com?utm_medium=email&utm_source=footer>>.

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> To view this discussion visit https://groups.google.com/d/msgid/

> cloudlab-users/07ce8c9f-69a2-44e6-
> a884-8cf936ba202f%40flux.utah.edu <https://groups.google.com/d/
> msgid/cloudlab-users/07ce8c9f-69a2-44e6-
> a884-8cf936ba202f%40flux.utah.edu>.

>
> --
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> cloudlab-users/

> CAGXJAmwQSyYPdPwEGB4SpJ0b28BSwPQK8Z2p81vBaV3FeaRRRw%40mail.gmail.com
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> utm_medium=email&utm_source=footer>.

John Ousterhout

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Jan 30, 2026, 5:02:19 PMJan 30

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Thanks. Maybe I am missing it, but I don't see a kernel config file in the email thread you linked to. I'll try the specific config lines that you sent. While I'm doing this, I'd like to make sure I'm configuring for MLX5 as well, since I'll need that next week. These are the lines currently in my .config:

CONFIG_MLX5_CORE=y
# CONFIG_MLX5_FPGA is not set
CONFIG_MLX5_CORE_EN=y
CONFIG_MLX5_MPFS=y
# CONFIG_MLX5_CORE_IPOIB is not set

Is that enough?

-John-

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David M Johnson

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Jan 30, 2026, 5:16:02 PMJan 30

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On 1/30/26 15:01, John Ousterhout wrote:
> Thanks. Maybe I am missing it, but I don't see a kernel config file in
> the email thread you linked to. I'll try the specific config lines that
> you sent. While I'm doing this, I'd like to make sure I'm configuring
> for MLX5 as well, since I'll need that next week. These are the lines
> currently in my .config:

I'm just referring to the `/boot/config-*` files that come with each
Ubuntu distro kernel.

> CONFIG_MLX5_CORE=y
> # CONFIG_MLX5_FPGA is not set
> CONFIG_MLX5_CORE_EN=y
> CONFIG_MLX5_MPFS=y
> # CONFIG_MLX5_CORE_IPOIB is not set
>
> Is that enough?

I'd just go with what is in /boot/config-5.4.0-212-generic (below); I'm
sure you have a better idea than me which matter for your use case :).

CONFIG_MLX5_CORE=m
CONFIG_MLX5_ACCEL=y
CONFIG_MLX5_FPGA=y
CONFIG_MLX5_CORE_EN=y
CONFIG_MLX5_EN_ARFS=y
CONFIG_MLX5_EN_RXNFC=y
CONFIG_MLX5_MPFS=y
CONFIG_MLX5_ESWITCH=y
CONFIG_MLX5_CORE_EN_DCB=y
CONFIG_MLX5_CORE_IPOIB=y
CONFIG_MLX5_FPGA_IPSEC=y
CONFIG_MLX5_EN_IPSEC=y
CONFIG_MLX5_FPGA_TLS=y
CONFIG_MLX5_TLS=y
CONFIG_MLX5_EN_TLS=y
CONFIG_MLX5_SW_STEERING=y

> -John-

David

> On Fri, Jan 30, 2026 at 1:01 PM David M Johnson <john...@flux.utah.edu
> <mailto:john...@flux.utah.edu>> wrote:
>
> On 1/30/26 13:44, John Ousterhout wrote:
> > I have compiled a 4.18 kernel, installed it on the UBUNTU20-64-
> STD image
> > and tried rebooting. The machine seems to reboot OK, except there
> are
> > errors starting Emulab services. After the boot I can't connect
> to it
> > via ssh. Any suggestions on how I can fix this?
>
> It looks like your build does not include the required mlx4_en driver
> for the m510s, so the public control net interface did not get an
> address via DHCP. You can see driver/firmware requirements for a node
> type by running `sudo lshw -c net` on one of your up machines, then
> check your build for the module `sudo modinfo mlx4_en`. Oftentimes we
> suggest you start your custom build from the default Ubuntu
> /boot/config-* kernel config (as in
> https://groups.google.com/g/cloudlab-users/c/y3SwBbUs2oE/m/

> M67jRhFSAAAJ <https://groups.google.com/g/cloudlab-users/c/
> y3SwBbUs2oE/m/M67jRhFSAAAJ>).

> > pg0.utah.cloudlab.us <http://pg0.utah.cloudlab.us>
> <mailto:ous...@node0.ouster-287877.homa-
> <mailto:ous...@node0.ouster-287877.homa->
> > pg0.utah.cloudlab.us <http://pg0.utah.cloudlab.us>>) (gcc version

> <mailto:dm-d...@redhat.com <mailto:dm-d...@redhat.com>>

> <mailto:john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>>> wrote:
> >
> > I will give UBUNTU20-64-STD a try; thanks for all of the
> information!
> >
> > -John-
> >
> > On Wed, Jan 28, 2026 at 8:56 AM David M Johnson
> > <john...@flux.utah.edu <mailto:john...@flux.utah.edu>

> wiki.ubuntu.com/Kernel/LTSEnablementStack> <https://
> > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://

> wiki.ubuntu.com/Kernel/LTSEnablementStack>>. This provides
> > updated, supported Ubuntu kernels newer than the original
> release
> > kernel. E.g. Ubuntu 18 defaulted to 4.15, but then -hwe
> builds
> > were
> > added for 4.18, 5.4, etc. You'll have to get these out
> of the
> > Ubuntu
> > archive for the Ubuntu 18 4.18 kernels (e.g.
> > https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-signed-

> <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-signed->
> > hwe/ <https://us.archive.ubuntu.com/ubuntu/pool/main/l/
> linux- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux->

> > signed-hwe/>, grep
> > for 4.18.0-25).
> >
> > > -John-
> >
> > David
> >
> > > On Wed, Jan 28, 2026 at 7:03 AM David M Johnson
> > <john...@flux.utah.edu <mailto:john...@flux.utah.edu>
> <mailto:john...@flux.utah.edu <mailto:john...@flux.utah.edu>>
> > > <mailto:john...@flux.utah.edu
> <mailto:john...@flux.utah.edu>
> > <mailto:john...@flux.utah.edu
> <mailto:john...@flux.utah.edu>>>> wrote:
> > >
> > > On 1/27/26 22:04, john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>
> > <mailto:john.ou...@gmail.com

> <mailto:john.ou...@gmail.com>> <mailto:john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>
> > <mailto:john.ou...@gmail.com <mailto:john.ou...@gmail.com>>>

> > kernel.ubuntu.com/mainline/v4.18.20/ <http://kernel.ubuntu.com/
> mainline/v4.18.20/>> <https://
> > > kernel.ubuntu.com/mainline/v4.18.20/ <http://

> kernel.ubuntu.com/mainline/v4.18.20/> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/ <http://kernel.ubuntu.com/
> mainline/v4.18.20/>>> , and download and install
> > > manually with dpkg:
> > >
> > > For instance on a d430:
> > >
> > > $ wget \
> > >
> > > https://kernel.ubuntu.com/mainline/v4.18.20/linux-

> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-> <https://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>
> > >
> > headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb
> > <https://
> > > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://

> kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>
> > >
> headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb>
> > > \
> > >
> > > https://kernel.ubuntu.com/mainline/v4.18.20/linux-

> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-> <https://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>
> > > headers-4.18.20-041820-
> > generic_4.18.20-041820.201812030624_amd64.deb
> > > <https://kernel.ubuntu.com/mainline/v4.18.20/
> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->

> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux->>
> > > headers-4.18.20-041820-
> > generic_4.18.20-041820.201812030624_amd64.deb>
> > > \
> > >
> > > https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> image- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->>
> > > unsigned-4.18.20-041820-
> > > generic_4.18.20-041820.201812030624_amd64.deb
> <https://
> > > kernel.ubuntu.com/mainline/v4.18.20/linux-image-

> <http://kernel.ubuntu.com/mainline/v4.18.20/linux-image-> <http://

> > kernel.ubuntu.com/mainline/v4.18.20/linux-image- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-image->>
> > > unsigned-4.18.20-041820-
> > generic_4.18.20-041820.201812030624_amd64.deb>
> > > \
> > >
> > > https://kernel.ubuntu.com/mainline/v4.18.20/linux-

> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-> <https://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>
> > > modules-4.18.20-041820-
> > generic_4.18.20-041820.201812030624_amd64.deb
> > > <https://kernel.ubuntu.com/mainline/v4.18.20/
> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->

> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux->>
> > > modules-4.18.20-041820-
> > generic_4.18.20-041820.201812030624_amd64.deb>
> > >
> > > $ dpkg -i *.deb
> > >
> > > You might also try the Ubuntu 18 4.18 HWE kernel
> packages
> > if you need
> > > anything from the modules-extra package.
> > >
> > > > -John-
> > >
> > > David
> > >
> > > --
> > > You received this message because you are
> subscribed to
> > the Google
> > > Groups "cloudlab-users" group.
> > > To unsubscribe from this group and stop receiving
> emails
> > from it,
> > > send an email to cloudlab-
> > users+un...@googlegroups.com

> > > To view this discussion visit https://

> groups.google.com/ <https://groups.google.com/>
> > d/msgid/ <https://groups.google.com/d/msgid/ <https://
> groups.google.com/d/msgid/>>
> > > cloudlab-users/f8a2e6b3-65bf-4646-ab10-
> > ccf8ae7c05cb%40flux.utah.edu <http://40flux.utah.edu>
> <http://40flux.utah.edu <http://40flux.utah.edu>>
> > > <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/>
> > <https://groups.google.com/d/msgid/cloudlab-users/

> <https://groups.google.com/d/msgid/cloudlab-users/>>
> > > f8a2e6b3-65bf-4646-ab10-
> ccf8ae7c05cb%40flux.utah.edu <http://40flux.utah.edu>

> > <http://40flux.utah.edu <http://40flux.utah.edu>>>.

> > >
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> > msgid/ <https://groups.google.com/d/msgid/ <https://
> groups.google.com/d/msgid/>>
> > > cloudlab-users/
> > >
> >
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> > > <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/> <https://
> > groups.google.com/d/msgid/cloudlab-users/ <http://
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> > >
> >
> CAGXJAmxEc25HWU%3DnSc5F0Aq7sdJC%3D1d3k6Ku2GrPN4cTt7CFcw%40mail.gmail.com?utm_medium=email&utm_source=footer <http://40mail.gmail.com?utm_medium=email&utm_source=footer> <http://40mail.gmail.com?utm_medium=email&utm_source=footer <http://40mail.gmail.com?utm_medium=email&utm_source=footer>>>.

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> <mailto:cloudlab-users%252Buns...@googlegroups.com>>.
> > To view this discussion visit https://groups.google.com/
> d/msgid/ <https://groups.google.com/d/msgid/>

> > cloudlab-users/07ce8c9f-69a2-44e6-
> > a884-8cf936ba202f%40flux.utah.edu
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> > msgid/cloudlab-users/07ce8c9f-69a2-44e6-
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> > To view this discussion visit https://groups.google.com/d/msgid/
> <https://groups.google.com/d/msgid/>
> > cloudlab-users/
> >

> CAGXJAmwQSyYPdPwEGB4SpJ0b28BSwPQK8Z2p81vBaV3FeaRRRw%40mail.gmail.com

> <http://40mail.gmail.com>
> > <https://groups.google.com/d/msgid/cloudlab-users/ <https://
> groups.google.com/d/msgid/cloudlab-users/>
> >

> CAGXJAmwQSyYPdPwEGB4SpJ0b28BSwPQK8Z2p81vBaV3FeaRRRw%40mail.gmail.com
> <http://40mail.gmail.com>?

> > utm_medium=email&utm_source=footer>.
>
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> <https://groups.google.com/d/msgid/cloudlab-
> users/2fc7e1e9-7bdf-43de-a824-6d79246a225b%40flux.utah.edu>.

> cloudlab-users/CAGXJAmyG%3DAAcFyQ24aVE7x-6_D13MXNM0eOWWCRD7kF-
> %3DgEVhg%40mail.gmail.com <https://groups.google.com/d/msgid/cloudlab-
> users/CAGXJAmyG%3DAAcFyQ24aVE7x-6_D13MXNM0eOWWCRD7kF-
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John Ousterhout

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Jan 30, 2026, 5:28:47 PMJan 30

to cloudla...@googlegroups.com

Thanks. With the changes you have suggested, the node reboots successfully except for one hitch: I can't ssh to it from node0 in the cluster ("no route to host"). I can ssh to it from my laptop outside CloudLab, though. Any thoughts?

Here is the experiment again:

https://www.cloudlab.us/status.php?uuid=d8628872-fca4-11f0-bc80-e4434b2381fc#

node1 is the node running the 4.18.0 kernel.

-John-

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David M Johnson

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Jan 30, 2026, 5:49:53 PMJan 30

to cloudla...@googlegroups.com

On 1/30/26 15:28, John Ousterhout wrote:
> Thanks. With the changes you have suggested, the node reboots
> successfully except for one hitch: I can't ssh to it from node0 in the
> cluster ("no route to host"). I can ssh to it from my laptop outside
> CloudLab, though. Any thoughts?

Because your profile sets the `vlan_tagging` option for the dataset
links on the first node, and because there is only one experiment iface
on the m510s, your main `lan` is also being placed in vlan_tagging mode
-- so the tags are exposed to the nodes, and thus vlan devices must be
created, and your custom kernel does not support vlan tagging. You can
see some errors as the `testbed` startup service attempted to configure
the experiment net on node1 in `sudo journalctl -b0 -u testbed`:

```
Jan 30 15:04:50 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
Checking Testbed interface configuration ...
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
Warning: vconfig is deprecated and might be removed in the future,
please migrate to ip(route2) as soon as possible!
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
Warning: vconfig is deprecated and might be removed in the future,
please migrate to ip(route2) as soon as possible!
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
RTNETLINK answers: Operation not supported
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
SIOCSIFADDR: No such device
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
vlan271: ERROR while getting interface flags: No such device
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
SIOCSIFNETMASK: No such device
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
SIOCSIFMTU: No such device
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
SIOCSIFHWADDR: No such device
Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us sh[2167]:
SIOCADDRT: Network is unreachable
```

You'll need to set `CONFIG_VLAN_8021Q=y` and build again.

> Here is the experiment again:
>

> https://www.cloudlab.us/status.php?uuid=d8628872-fca4-11f0-bc80-
> e4434b2381fc# <https://www.cloudlab.us/status.php?uuid=d8628872-
> fca4-11f0-bc80-e4434b2381fc#>
>

> node1 is the node running the 4.18.0 kernel.
>
> -John-

David

> On Fri, Jan 30, 2026 at 2:16 PM David M Johnson <john...@flux.utah.edu

> > <https://www.cloudlab.us/status.php?uuid=d8628872-fca4-11f0-
> bc80- <https://www.cloudlab.us/status.php?uuid=d8628872-fca4-11f0-
> bc80->>
> > > e4434b2381fc# <https://www.cloudlab.us/status.php?
> uuid=d8628872- <https://www.cloudlab.us/status.php?uuid=d8628872->
> > <https://www.cloudlab.us/status.php?uuid=d8628872- <https://

> <http://pg0.utah.cloudlab.us <http://pg0.utah.cloudlab.us>>

> > <mailto:ous...@node0.ouster-287877.homa-
> <mailto:ous...@node0.ouster-287877.homa->
> > <mailto:ous...@node0.ouster-287877.homa-
> <mailto:ous...@node0.ouster-287877.homa->>
> > > pg0.utah.cloudlab.us <http://pg0.utah.cloudlab.us>

> <http://pg0.utah.cloudlab.us <http://pg0.utah.cloudlab.us>>>) (gcc

> de...@redhat.com> <mailto:dm-d...@redhat.com <mailto:dm-
> de...@redhat.com>>

> > <mailto:john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>
> > <mailto:john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>>>> wrote:
> > >
> > > I will give UBUNTU20-64-STD a try; thanks for all of the
> > information!
> > >
> > > -John-
> > >
> > > On Wed, Jan 28, 2026 at 8:56 AM David M Johnson
> > > <john...@flux.utah.edu
> <mailto:john...@flux.utah.edu> <mailto:john...@flux.utah.edu
> <mailto:john...@flux.utah.edu>>

> <https://wiki.ubuntu.com/Kernel/LTSEnablementStack> <https://

> > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://
> wiki.ubuntu.com/Kernel/LTSEnablementStack>> <https://
> > > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://

> wiki.ubuntu.com/Kernel/LTSEnablementStack> <http://

> > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://
> wiki.ubuntu.com/Kernel/LTSEnablementStack>>>. This provides
> > > updated, supported Ubuntu kernels newer than the
> original
> > release
> > > kernel. E.g. Ubuntu 18 defaulted to 4.15, but
> then -hwe
> > builds
> > > were
> > > added for 4.18, 5.4, etc. You'll have to get
> these out
> > of the
> > > Ubuntu
> > > archive for the Ubuntu 18 4.18 kernels (e.g.
> > > https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-
> signed- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-signed->

> > <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-
> signed- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux-
> signed->>
> > > hwe/ <https://us.archive.ubuntu.com/ubuntu/pool/
> main/l/ <https://us.archive.ubuntu.com/ubuntu/pool/main/l/>
> > linux- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/

> <https://kernel.ubuntu.com/mainline/v4.18.20/> <https://

> > kernel.ubuntu.com/mainline/v4.18.20/ <http://kernel.ubuntu.com/
> mainline/v4.18.20/>> <https://
> > > kernel.ubuntu.com/mainline/v4.18.20/ <http://
> kernel.ubuntu.com/mainline/v4.18.20/> <http://kernel.ubuntu.com/
> <http://kernel.ubuntu.com/>
> > mainline/v4.18.20/>> <https://
> > > > kernel.ubuntu.com/mainline/v4.18.20/ <http://
> kernel.ubuntu.com/mainline/v4.18.20/> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/ <http://kernel.ubuntu.com/

> mainline/v4.18.20/>> <http://

> > > kernel.ubuntu.com/mainline/v4.18.20/ <http://
> kernel.ubuntu.com/mainline/v4.18.20/> <http://kernel.ubuntu.com/
> <http://kernel.ubuntu.com/>
> > mainline/v4.18.20/>>> , and download and install
> > > > manually with dpkg:
> > > >
> > > > For instance on a d430:
> > > >
> > > > $ wget \
> > > >

> > > > https://kernel.ubuntu.com/mainline/v4.18.20/
> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://

> kernel.ubuntu.com/mainline/v4.18.20/linux->> <https://

> > > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>>
> > > >
> > >
> headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb
> > > <https://
> > > > kernel.ubuntu.com/mainline/v4.18.20/linux-

> <http://kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->> <http://
> > > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>>
> > > >
> > headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb>
> > > > \
> > > >

> > > > https://kernel.ubuntu.com/mainline/v4.18.20/
> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://

> kernel.ubuntu.com/mainline/v4.18.20/linux->> <https://

> > > > headers-4.18.20-041820-
> > > generic_4.18.20-041820.201812030624_amd64.deb
> > > > <https://kernel.ubuntu.com/mainline/
> v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/>

> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://

> kernel.ubuntu.com/mainline/v4.18.20/linux->>>
> > > > headers-4.18.20-041820-
> > > generic_4.18.20-041820.201812030624_amd64.deb>
> > > > \
> > > >
> > > > https://kernel.ubuntu.com/mainline/v4.18.20/
> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->

> > image- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-

> image- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->>
> > > <https://kernel.ubuntu.com/mainline/v4.18.20/
> linux-image- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->>>
> > > > unsigned-4.18.20-041820-
> > > > generic_4.18.20-041820.201812030624_amd64.deb
> > <https://
> > > > kernel.ubuntu.com/mainline/v4.18.20/linux-
> image- <http://kernel.ubuntu.com/mainline/v4.18.20/linux-image->
> > <http://kernel.ubuntu.com/mainline/v4.18.20/linux-image-
> <http://kernel.ubuntu.com/mainline/v4.18.20/linux-image->> <http://
> > > kernel.ubuntu.com/mainline/v4.18.20/linux-image- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-image-> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/linux-image- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-image->>>
> > > > unsigned-4.18.20-041820-
> > > generic_4.18.20-041820.201812030624_amd64.deb>
> > > > \
> > > >

> > > > https://kernel.ubuntu.com/mainline/v4.18.20/
> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://

> kernel.ubuntu.com/mainline/v4.18.20/linux->> <https://

> > > > modules-4.18.20-041820-
> > > generic_4.18.20-041820.201812030624_amd64.deb
> > > > <https://kernel.ubuntu.com/mainline/
> v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/>

> > linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux->>
> > > <https://kernel.ubuntu.com/mainline/v4.18.20/
> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>>

> > > > modules-4.18.20-041820-
> > > generic_4.18.20-041820.201812030624_amd64.deb>
> > > >
> > > > $ dpkg -i *.deb
> > > >
> > > > You might also try the Ubuntu 18 4.18 HWE
> kernel
> > packages
> > > if you need
> > > > anything from the modules-extra package.
> > > >
> > > > > -John-
> > > >
> > > > David
> > > >
> > > > --
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> <mailto:cloudlab->

> > <mailto:cloudlab- <mailto:cloudlab->>
> > > users%2Bunsu...@googlegroups.com
> <mailto:users%252Buns...@googlegroups.com>

> > <mailto:users%252Buns...@googlegroups.com
> <mailto:users%25252Bun...@googlegroups.com>>>

> > > > <mailto:cloudlab- <mailto:cloudlab->
> > users%2Bunsu...@googlegroups.com
> <mailto:users%252Buns...@googlegroups.com> <mailto:cloudlab-

> <mailto:cloudlab->
> > users%252Buns...@googlegroups.com
> <mailto:users%25252Bun...@googlegroups.com>>
> > > <mailto:cloudlab-
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> > <mailto:cloudlab-users%25252Bun...@googlegroups.com
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> <https://groups.google.com/d/msgid/> <https://
> > groups.google.com/d/msgid/ <http://groups.google.com/d/msgid/>>>
> > > > cloudlab-users/f8a2e6b3-65bf-4646-ab10-
> > > ccf8ae7c05cb%40flux.utah.edu
> <http://40flux.utah.edu> <http://40flux.utah.edu
> <http://40flux.utah.edu>>
> > <http://40flux.utah.edu <http://40flux.utah.edu>

> <http://40flux.utah.edu <http://40flux.utah.edu>>>
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> cloudlab-users/ <https://groups.google.com/d/msgid/cloudlab-users/>

> > <https://groups.google.com/d/msgid/cloudlab-users/ <https://
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> > > <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/>
> > <https://groups.google.com/d/msgid/cloudlab-users/ <https://

> groups.google.com/d/msgid/cloudlab-users/>>>
> > > > f8a2e6b3-65bf-4646-ab10-
> > ccf8ae7c05cb%40flux.utah.edu <http://40flux.utah.edu>
> <http://40flux.utah.edu <http://40flux.utah.edu>>

> > > <http://40flux.utah.edu <http://40flux.utah.edu>

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> > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
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> <https://groups.google.com/d/msgid/> <https://
> > groups.google.com/d/msgid/ <http://groups.google.com/d/msgid/>>>
> > > > cloudlab-users/
> > > >
> > >
> >
> CAGXJAmxEc25HWU%3DnSc5F0Aq7sdJC%3D1d3k6Ku2GrPN4cTt7CFcw%40mail.gmail.com <http://40mail.gmail.com> <http://40mail.gmail.com <http://40mail.gmail.com>> <http://40mail.gmail.com <http://40mail.gmail.com> <http://40mail.gmail.com <http://40mail.gmail.com>>>
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> users/ <https://groups.google.com/d/msgid/cloudlab-users/>

> > <https://groups.google.com/d/msgid/cloudlab-users/ <https://
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> > > <mailto:cloudlab-
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> users%252Buns...@googlegroups.com>
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> > > cloudlab-users/07ce8c9f-69a2-44e6-
> > > a884-8cf936ba202f%40flux.utah.edu

> <http://40flux.utah.edu>
> > <http://40flux.utah.edu <http://40flux.utah.edu>> <https://

> groups.google.com/d/ <https://groups.google.com/d/> <https://
> > groups.google.com/d/ <http://groups.google.com/d/>>
> > > msgid/cloudlab-users/07ce8c9f-69a2-44e6-
> > > a884-8cf936ba202f%40flux.utah.edu

> <http://40flux.utah.edu> <http://40flux.utah.edu
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> > > <mailto:cloudlab-user...@googlegroups.com
> <mailto:cloudlab-users%2Bunsu...@googlegroups.com>
> > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>>>.

> > > To view this discussion visit https://groups.google.com/d/
> msgid/ <https://groups.google.com/d/msgid/>

> > <https://groups.google.com/d/msgid/ <https://
> groups.google.com/d/msgid/>>
> > > cloudlab-users/
> > >
> >

> CAGXJAmwQSyYPdPwEGB4SpJ0b28BSwPQK8Z2p81vBaV3FeaRRRw%40mail.gmail.com <http://40mail.gmail.com>

> > <http://40mail.gmail.com <http://40mail.gmail.com>>
> > > <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/> <https://
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> > >
> >

> CAGXJAmwQSyYPdPwEGB4SpJ0b28BSwPQK8Z2p81vBaV3FeaRRRw%40mail.gmail.com <http://40mail.gmail.com>
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> msgid/ <https://groups.google.com/d/msgid/>
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> > cloudlab-users/CAGXJAmyG%3DAAcFyQ24aVE7x-6_D13MXNM0eOWWCRD7kF-
> > %3DgEVhg%40mail.gmail.com <http://40mail.gmail.com> <https://
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> msgid/cloudlab->
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> > %3DgEVhg%40mail.gmail.com?utm_medium=email&utm_source=footer

> send an email to cloudlab-user...@googlegroups.com

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> cloudlab-users/CAGXJAmz-YxAaK%3DY-%3D8Zu9efajxCLtmSbLV7W5-
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Mike Hibler

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Jan 30, 2026, 5:51:13 PMJan 30

to cloudla...@googlegroups.com

The vlan device did not setup. Maybe some more missing modules?

> RTNETLINK answers: Operation not supported

> SIOCSIFADDR: No such device

> vlan271: ERROR while getting interface flags: No such device

> SIOCSIFNETMASK: No such device
> SIOCSIFMTU: No such device
> SIOCSIFHWADDR: No such device
> SIOCADDRT: Network is unreachable

or this could be a low-level KPI mismatch in the netlink interface.

> CAGXJAmz-YxAaK%3DY-%3D8Zu9efajxCLtmSbLV7W5-z55f8Oed0v9w%40mail.gmail.com.

John Ousterhout

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Jan 30, 2026, 5:56:15 PMJan 30

to cloudla...@googlegroups.com

Ahah; thanks. I have switched over to use the .config file from Ubuntu, which is configured with VLAN support. I'm recompiling now, so hopefully that will fix it.

Do I need to have vlan tagging in my profile? I inherited that from a profile that I started with and just assumed it was required. I'd be happy to drop it if it isn't needed.

-John-

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David M Johnson

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Jan 30, 2026, 6:36:28 PMJan 30

to cloudla...@googlegroups.com

On 1/30/26 15:55, John Ousterhout wrote:
> Ahah; thanks. I have switched over to use the .config file from Ubuntu,
> which is configured with VLAN support. I'm recompiling now, so hopefully
> that will fix it.
>
> Do I need to have vlan tagging in my profile? I inherited that from a
> profile that I started with and just assumed it was required. I'd be
> happy to drop it if it isn't needed.

I believe that the only time you need to force `vlan_tagging = True` is
if your use case needs to see the 802.11q tags at the host edge. But I
did neglect to mention that it will also automatically be enabled for
all your links/lans in this case, because there is only a single
experiment iface, and you've set `link_multiplexing = True`. In order
to multiplex links, we have to automatically enable vlan_tagging.

So, there is no need to make a change -- your experiment lan (and links)
will get vlan tags on any node type that has only one expt iface (or
single expt iface that matches your lan/link bandwidth requirements) --
so that we can multiplex.

> -John-

David

> On Fri, Jan 30, 2026 at 2:49 PM David M Johnson <john...@flux.utah.edu

> <mailto:john...@flux.utah.edu>> wrote:
>
> On 1/30/26 15:28, John Ousterhout wrote:
> > Thanks. With the changes you have suggested, the node reboots
> > successfully except for one hitch: I can't ssh to it from node0
> in the
> > cluster ("no route to host"). I can ssh to it from my laptop outside
> > CloudLab, though. Any thoughts?
>
> Because your profile sets the `vlan_tagging` option for the dataset
> links on the first node, and because there is only one experiment iface
> on the m510s, your main `lan` is also being placed in vlan_tagging mode
> -- so the tags are exposed to the nodes, and thus vlan devices must be
> created, and your custom kernel does not support vlan tagging. You can
> see some errors as the `testbed` startup service attempted to configure
> the experiment net on node1 in `sudo journalctl -b0 -u testbed`:
>
> ```
> Jan 30 15:04:50 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> Checking Testbed interface configuration ...
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> Warning: vconfig is deprecated and might be removed in the future,
> please migrate to ip(route2) as soon as possible!
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> Warning: vconfig is deprecated and might be removed in the future,
> please migrate to ip(route2) as soon as possible!
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> RTNETLINK answers: Operation not supported
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> SIOCSIFADDR: No such device
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> vlan271: ERROR while getting interface flags: No such device
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> SIOCSIFNETMASK: No such device
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> SIOCSIFMTU: No such device
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> SIOCSIFHWADDR: No such device
> Jan 30 15:04:52 node1.ouster-287877.homa-pg0.utah.cloudlab.us

> <http://node1.ouster-287877.homa-pg0.utah.cloudlab.us> sh[2167]:

> SIOCADDRT: Network is unreachable
> ```
>
> You'll need to set `CONFIG_VLAN_8021Q=y` and build again.
>
> > Here is the experiment again:
> >
> > https://www.cloudlab.us/status.php?uuid=d8628872-fca4-11f0-bc80-
> <https://www.cloudlab.us/status.php?uuid=d8628872-fca4-11f0-bc80->
> > e4434b2381fc# <https://www.cloudlab.us/status.php?uuid=d8628872-
> <https://www.cloudlab.us/status.php?uuid=d8628872->
> > fca4-11f0-bc80-e4434b2381fc#>
> >
> > node1 is the node running the 4.18.0 kernel.
> >
> > -John-
>
> David
>
> > On Fri, Jan 30, 2026 at 2:16 PM David M Johnson
> <john...@flux.utah.edu <mailto:john...@flux.utah.edu>

> > > <mailto:john...@flux.utah.edu
> <mailto:john...@flux.utah.edu> <mailto:john...@flux.utah.edu
> <mailto:john...@flux.utah.edu>>>>
> > wrote:
> > >

> > <https://groups.google.com/g/cloudlab-users/c/ <https://

> groups.google.com/g/cloudlab-users/c/>>
> > > y3SwBbUs2oE/m/M67jRhFSAAAJ>).
> > > Or, here are the specific config bits you would
> lift from
> > a stock
> > > Ubuntu config:
> > >
> > > CONFIG_MLX4_EN=m
> > > CONFIG_MLX4_EN_DCB=y
> > > CONFIG_MLX4_CORE=m
> > > CONFIG_MLX4_DEBUG=y
> > > CONFIG_MLX4_CORE_GEN2=y
> > >
> > > David
> > >
> > > > You can see the problems in the log for node2 of this
> > experiment:
> > > >
> > > > https://www.cloudlab.us/status.php?uuid=d8628872-

> uuid=d8628872- <https://www.cloudlab.us/status.php?uuid=d8628872->>
> > > <https://www.cloudlab.us/status.php?uuid=d8628872-

> <https://www.cloudlab.us/status.php?uuid=d8628872-> <https://
> > www.cloudlab.us/status.php?uuid=d8628872- <http://

> de...@redhat.com> <mailto:dm- <mailto:dm->
> > de...@redhat.com <mailto:de...@redhat.com>> <mailto:dm-
> de...@redhat.com <mailto:dm-d...@redhat.com> <mailto:dm- <mailto:dm->
> > de...@redhat.com <mailto:de...@redhat.com>>>

> > > <mailto:john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>
> > <mailto:john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>>
> > > <mailto:john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>
> > <mailto:john.ou...@gmail.com
> <mailto:john.ou...@gmail.com>>>>> wrote:
> > > >
> > > > I will give UBUNTU20-64-STD a try; thanks for
> all of the
> > > information!
> > > >
> > > > -John-
> > > >
> > > > On Wed, Jan 28, 2026 at 8:56 AM David M Johnson
> > > > <john...@flux.utah.edu
> <mailto:john...@flux.utah.edu>
> > <mailto:john...@flux.utah.edu
> <mailto:john...@flux.utah.edu>> <mailto:john...@flux.utah.edu
> <mailto:john...@flux.utah.edu>
> > <mailto:john...@flux.utah.edu <mailto:john...@flux.utah.edu>>>

> > <https://wiki.ubuntu.com/Kernel/LTSEnablementStack <https://

> wiki.ubuntu.com/Kernel/LTSEnablementStack>> <https://
> > > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://
> wiki.ubuntu.com/Kernel/LTSEnablementStack> <http://
> > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://
> wiki.ubuntu.com/Kernel/LTSEnablementStack>>> <https://
> > > > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://
> wiki.ubuntu.com/Kernel/LTSEnablementStack> <http://
> > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://

> wiki.ubuntu.com/Kernel/LTSEnablementStack>> <http://

> > > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://
> wiki.ubuntu.com/Kernel/LTSEnablementStack> <http://
> > wiki.ubuntu.com/Kernel/LTSEnablementStack <http://
> wiki.ubuntu.com/Kernel/LTSEnablementStack>>>>. This provides
> > > > updated, supported Ubuntu kernels newer
> than the
> > original
> > > release
> > > > kernel. E.g. Ubuntu 18 defaulted to 4.15, but
> > then -hwe
> > > builds
> > > > were
> > > > added for 4.18, 5.4, etc. You'll have to get
> > these out
> > > of the
> > > > Ubuntu
> > > > archive for the Ubuntu 18 4.18 kernels (e.g.
> > > > https://us.archive.ubuntu.com/ubuntu/pool/main/l/

> linux- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux->
> > signed- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/
> linux-signed- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/
> linux-signed->>

> > > <https://us.archive.ubuntu.com/ubuntu/pool/main/l/
> linux- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux->

> > signed- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/
> linux- <https://us.archive.ubuntu.com/ubuntu/pool/main/l/linux->
> > signed->>
> > > > hwe/ <https://us.archive.ubuntu.com/ubuntu/
> pool/ <https://us.archive.ubuntu.com/ubuntu/pool/>
> > main/l/ <https://us.archive.ubuntu.com/ubuntu/pool/main/l/
> <https://us.archive.ubuntu.com/ubuntu/pool/main/l/>>
> > > linux- <https://us.archive.ubuntu.com/ubuntu/pool/

> > <mailto:john.ou...@gmail.com <mailto:john.ou...@gmail.com>>>>>

> v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/>
> > <https://kernel.ubuntu.com/mainline/v4.18.20/ <https://
> kernel.ubuntu.com/mainline/v4.18.20/>> <https://

> > > kernel.ubuntu.com/mainline/v4.18.20/ <http://
> kernel.ubuntu.com/mainline/v4.18.20/> <http://kernel.ubuntu.com/
> <http://kernel.ubuntu.com/>
> > mainline/v4.18.20/>> <https://
> > > > kernel.ubuntu.com/mainline/v4.18.20/ <http://
> kernel.ubuntu.com/mainline/v4.18.20/> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/ <http://kernel.ubuntu.com/

> mainline/v4.18.20/>> <http://kernel.ubuntu.com/ <http://
> kernel.ubuntu.com/>

> > <http://kernel.ubuntu.com/ <http://kernel.ubuntu.com/>>
> > > mainline/v4.18.20/>> <https://
> > > > > kernel.ubuntu.com/mainline/v4.18.20/

> <http://kernel.ubuntu.com/mainline/v4.18.20/> <http://

> > kernel.ubuntu.com/mainline/v4.18.20/ <http://kernel.ubuntu.com/
> mainline/v4.18.20/>> <http://
> > > kernel.ubuntu.com/mainline/v4.18.20/ <http://
> kernel.ubuntu.com/mainline/v4.18.20/> <http://kernel.ubuntu.com/
> <http://kernel.ubuntu.com/>

> > mainline/v4.18.20/>> <http://
> > > > kernel.ubuntu.com/mainline/v4.18.20/ <http://
> kernel.ubuntu.com/mainline/v4.18.20/> <http://

> > kernel.ubuntu.com/mainline/v4.18.20/ <http://kernel.ubuntu.com/
> mainline/v4.18.20/>> <http://kernel.ubuntu.com/ <http://
> kernel.ubuntu.com/>

> > <http://kernel.ubuntu.com/ <http://kernel.ubuntu.com/>>
> > > mainline/v4.18.20/>>> , and download and install
> > > > > manually with dpkg:
> > > > >
> > > > > For instance on a d430:
> > > > >
> > > > > $ wget \
> > > > >

> > > > > https://kernel.ubuntu.com/mainline/
> v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/>
> > linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux->>

> > > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-> <https://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://

> kernel.ubuntu.com/mainline/v4.18.20/linux->>> <https://
> > > > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://

> kernel.ubuntu.com/mainline/v4.18.20/linux->> <http://
> > > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>>>
> > > > >
> > > >
> > headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb

> > > > <https://
> > > > > kernel.ubuntu.com/mainline/v4.18.20/
> linux- <http://kernel.ubuntu.com/mainline/v4.18.20/linux->

> > <http://kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->> <http://
> > > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>> <http://

> > > > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://

> kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://
> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->> <http://
> > > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux-> <http://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>>>
> > > > >
> > >
> headers-4.18.20-041820_4.18.20-041820.201812030624_all.deb>
> > > > > \
> > > > >

> > > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-> <https://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://

> > > > > headers-4.18.20-041820-
> > > > generic_4.18.20-041820.201812030624_amd64.deb
> > > > > <https://kernel.ubuntu.com/mainline/
> <https://kernel.ubuntu.com/mainline/>
> > v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/

> <https://kernel.ubuntu.com/mainline/v4.18.20/>>
> > > linux- <https://kernel.ubuntu.com/mainline/v4.18.20/
> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux- <https://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>>

> > > > <https://kernel.ubuntu.com/mainline/
> v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/>
> > linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux->>

> > > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-> <https://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>>>
> > > > > headers-4.18.20-041820-
> > > > generic_4.18.20-041820.201812030624_amd64.deb>
> > > > > \
> > > > >
> > > > > https://kernel.ubuntu.com/mainline/
> v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/>
> > linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux->>

> > > image- <https://kernel.ubuntu.com/mainline/v4.18.20/

> linux- <https://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > image- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> image- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->>>
> > > > <https://kernel.ubuntu.com/mainline/

> v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/>
> > linux-image- <https://kernel.ubuntu.com/mainline/v4.18.20/
> linux-image- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->>

> > > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> image- <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->
> > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-image->>>>
> > > > > unsigned-4.18.20-041820-
> > > > >
> generic_4.18.20-041820.201812030624_amd64.deb
> > > <https://
> > > > > kernel.ubuntu.com/mainline/v4.18.20/

> linux- <http://kernel.ubuntu.com/mainline/v4.18.20/linux->
> > image- <http://kernel.ubuntu.com/mainline/v4.18.20/linux-
> image- <http://kernel.ubuntu.com/mainline/v4.18.20/linux-image->>

> > > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-> <https://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://

> > > > > modules-4.18.20-041820-
> > > > generic_4.18.20-041820.201812030624_amd64.deb
> > > > > <https://kernel.ubuntu.com/mainline/
> <https://kernel.ubuntu.com/mainline/>
> > v4.18.20/ <https://kernel.ubuntu.com/mainline/v4.18.20/

> > > <https://kernel.ubuntu.com/mainline/v4.18.20/linux-
> <https://kernel.ubuntu.com/mainline/v4.18.20/linux-> <https://

> > kernel.ubuntu.com/mainline/v4.18.20/linux- <http://
> kernel.ubuntu.com/mainline/v4.18.20/linux->>>>
> > > > > modules-4.18.20-041820-
> > > > generic_4.18.20-041820.201812030624_amd64.deb>
> > > > >

> > > > > $ dpkg -i *.deb
> > > > >
> > > > > You might also try the Ubuntu 18
> 4.18 HWE
> > kernel
> > > packages
> > > > if you need
> > > > > anything from the modules-extra package.
> > > > >
> > > > > > -John-
> > > > >
> > > > > David
> > > > >
> > > > > --
> > > > > You received this message because
> you are
> > > subscribed to
> > > > the Google
> > > > > Groups "cloudlab-users" group.
> > > > > To unsubscribe from this group and stop
> > receiving
> > > emails
> > > > from it,
> > > > > send an email to cloudlab-
> > > > users+un...@googlegroups.com
> <mailto:users%2Bunsu...@googlegroups.com>
> > <mailto:users%2Bunsu...@googlegroups.com
> <mailto:users%252Buns...@googlegroups.com>>

> > > <mailto:users%2Bunsu...@googlegroups.com

> <mailto:users%252Buns...@googlegroups.com>
> > <mailto:users%252Buns...@googlegroups.com
> <mailto:users%25252Bun...@googlegroups.com>>>
> <mailto:cloudlab- <mailto:cloudlab->
> > <mailto:cloudlab- <mailto:cloudlab->>

> > > <mailto:cloudlab- <mailto:cloudlab-> <mailto:cloudlab-

> <mailto:cloudlab->>>
> > > > users%2Bunsu...@googlegroups.com
> <mailto:users%252Buns...@googlegroups.com>
> > <mailto:users%252Buns...@googlegroups.com
> <mailto:users%25252Bun...@googlegroups.com>>

> > > <mailto:users%252Buns...@googlegroups.com
> <mailto:users%25252Bun...@googlegroups.com>
> > <mailto:users%25252Bun...@googlegroups.com
> <mailto:users%2525252Bu...@googlegroups.com>>>>

> > > > > <mailto:cloudlab- <mailto:cloudlab->
> <mailto:cloudlab- <mailto:cloudlab->>
> > > users%2Bunsu...@googlegroups.com
> <mailto:users%252Buns...@googlegroups.com>
> > <mailto:users%252Buns...@googlegroups.com
> <mailto:users%25252Bun...@googlegroups.com>> <mailto:cloudlab-
> <mailto:cloudlab->

> > <mailto:cloudlab- <mailto:cloudlab->>
> > > users%252Buns...@googlegroups.com
> <mailto:users%25252Bun...@googlegroups.com>

> > <mailto:users%25252Bun...@googlegroups.com
> <mailto:users%2525252Bu...@googlegroups.com>>>

> > > > <mailto:cloudlab- <mailto:cloudlab->
> > users%252Buns...@googlegroups.com
> <mailto:users%25252Bun...@googlegroups.com> <mailto:cloudlab-

> <mailto:cloudlab->
> > users%25252Bun...@googlegroups.com
> <mailto:users%2525252Bu...@googlegroups.com>>
> > > <mailto:cloudlab-
> users%25252Bun...@googlegroups.com <mailto:cloudlab-
> users%2525252Bu...@googlegroups.com>
> > <mailto:cloudlab-users%2525252Bu...@googlegroups.com
> <mailto:cloudlab-users%252525252B...@googlegroups.com>>>>>.

> > > > > To view this discussion visit https://

> > > groups.google.com/ <http://groups.google.com/> <http://

> groups.google.com/ <http://groups.google.com/>> <https://
> > groups.google.com/ <http://groups.google.com/> <https://
> groups.google.com/ <https://groups.google.com/>>>

> > > > d/msgid/ <https://groups.google.com/d/

> msgid/ <https://groups.google.com/d/msgid/>
> > <https://groups.google.com/d/msgid/ <https://

> groups.google.com/d/msgid/>> <https://
> > > groups.google.com/d/msgid/ <http://groups.google.com/d/
> msgid/> <http://groups.google.com/d/msgid/ <http://

> groups.google.com/d/msgid/>>>>
> > > > > cloudlab-users/f8a2e6b3-65bf-4646-ab10-
> > > > ccf8ae7c05cb%40flux.utah.edu
> <http://40flux.utah.edu>
> > <http://40flux.utah.edu <http://40flux.utah.edu>>
> <http://40flux.utah.edu <http://40flux.utah.edu>
> > <http://40flux.utah.edu <http://40flux.utah.edu>>>
> > > <http://40flux.utah.edu <http://40flux.utah.edu>
> <http://40flux.utah.edu <http://40flux.utah.edu>>
> > <http://40flux.utah.edu <http://40flux.utah.edu>

> <http://40flux.utah.edu <http://40flux.utah.edu>>>>
> > > > > <https://groups.google.com/d/msgid/

> <https://groups.google.com/d/msgid/>
> > cloudlab-users/ <https://groups.google.com/d/msgid/cloudlab-

> users/ <https://groups.google.com/d/msgid/cloudlab-users/>>

> > > <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/> <https://

> > groups.google.com/d/msgid/cloudlab-users/ <http://
> groups.google.com/d/msgid/cloudlab-users/>>>
> > > > <https://groups.google.com/d/msgid/

> cloudlab-users/ <https://groups.google.com/d/msgid/cloudlab-users/>
> > <https://groups.google.com/d/msgid/cloudlab-users/ <https://
> groups.google.com/d/msgid/cloudlab-users/>>
> > > <https://groups.google.com/d/msgid/cloudlab-users/

> <https://groups.google.com/d/msgid/cloudlab-users/> <https://
> > groups.google.com/d/msgid/cloudlab-users/ <http://
> groups.google.com/d/msgid/cloudlab-users/>>>>

> > > > > f8a2e6b3-65bf-4646-ab10-
> > > ccf8ae7c05cb%40flux.utah.edu <http://40flux.utah.edu>
> <http://40flux.utah.edu <http://40flux.utah.edu>>
> > <http://40flux.utah.edu <http://40flux.utah.edu>
> <http://40flux.utah.edu <http://40flux.utah.edu>>>

> > > > <http://40flux.utah.edu
> <http://40flux.utah.edu> <http://40flux.utah.edu
> <http://40flux.utah.edu>>
> > <http://40flux.utah.edu <http://40flux.utah.edu>

> <http://40flux.utah.edu <http://40flux.utah.edu>>>>>.
> > > > >
> > > > > --
> > > > > You received this message because you are
> > subscribed
> > > to the
> > > > Google
> > > > > Groups "cloudlab-users" group.
> > > > > To unsubscribe from this group and stop
> receiving
> > > emails from
> > > > it, send
> > > > > an email to cloudlab-
> > > users+un...@googlegroups.com
> <mailto:users%2Bunsu...@googlegroups.com>

> > > > > <mailto:cloudlab- <mailto:cloudlab->

> > users+un...@googlegroups.com
> <mailto:users%2Bunsu...@googlegroups.com> <mailto:cloudlab-
> <mailto:cloudlab->
> > users%2Bunsu...@googlegroups.com
> <mailto:users%252Buns...@googlegroups.com>>
> > > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>
> > <mailto:cloudlab-users%252Buns...@googlegroups.com
> <mailto:cloudlab-users%25252Bun...@googlegroups.com>>>

> > > groups.google.com/d/ <http://groups.google.com/d/>
> <http://groups.google.com/d/ <http://groups.google.com/d/>> <https://

> > groups.google.com/d/ <http://groups.google.com/d/> <https://
> groups.google.com/d/ <https://groups.google.com/d/>>>
> > > > msgid/ <https://groups.google.com/d/msgid/
> <https://groups.google.com/d/msgid/>

> > <https://groups.google.com/d/msgid/ <https://
> groups.google.com/d/msgid/>> <https://

> > users/ <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/>>

> > > <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/> <https://
> > groups.google.com/d/msgid/cloudlab-users/ <http://

> groups.google.com/d/msgid/cloudlab-users/>>> <https://
> > > > groups.google.com/d/msgid/cloudlab-users/ <http://
> groups.google.com/d/msgid/cloudlab-users/> <http://
> > groups.google.com/d/msgid/cloudlab-users/ <http://

> groups.google.com/d/msgid/cloudlab-users/>> <http://

> > > groups.google.com/d/msgid/cloudlab-users/ <http://
> groups.google.com/d/msgid/cloudlab-users/> <http://
> > groups.google.com/d/msgid/cloudlab-users/ <http://
> groups.google.com/d/msgid/cloudlab-users/>>>>
> > > > >
> > > >
> > >
> >

> > > >
> > > > --
> > > > You received this message because you are
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> > > > cloudlab-users/07ce8c9f-69a2-44e6-
> > > > a884-8cf936ba202f%40flux.utah.edu
> <http://40flux.utah.edu>
> > <http://40flux.utah.edu <http://40flux.utah.edu>>

> > > <http://40flux.utah.edu <http://40flux.utah.edu>
> <http://40flux.utah.edu <http://40flux.utah.edu>>> <https://

> > groups.google.com/d/ <http://groups.google.com/d/> <https://

> groups.google.com/d/ <https://groups.google.com/d/>> <https://
> > > groups.google.com/d/ <http://groups.google.com/d/>
> <http://groups.google.com/d/ <http://groups.google.com/d/>>>

> > > > msgid/cloudlab-users/07ce8c9f-69a2-44e6-
> > > > a884-8cf936ba202f%40flux.utah.edu
> <http://40flux.utah.edu>
> > <http://40flux.utah.edu <http://40flux.utah.edu>>

> <http://40flux.utah.edu <http://40flux.utah.edu>
> > <http://40flux.utah.edu <http://40flux.utah.edu>>>>.
> > > >
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> <mailto:cloudlab-users%25252Bun...@googlegroups.com>>>
> > > > <mailto:cloudlab-user...@googlegroups.com

> <mailto:cloudlab-users%2Bunsu...@googlegroups.com>
> > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>>

> > > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>

> > <mailto:cloudlab-users%252Buns...@googlegroups.com
> <mailto:cloudlab-users%25252Bun...@googlegroups.com>>>>.
> > > > To view this discussion visit https://

> groups.google.com/d/ <https://groups.google.com/d/>
> > msgid/ <https://groups.google.com/d/msgid/ <https://

> groups.google.com/d/msgid/>>
> > > <https://groups.google.com/d/msgid/ <https://

> groups.google.com/d/msgid/> <https://
> > groups.google.com/d/msgid/ <http://groups.google.com/d/msgid/>>>
> > > > cloudlab-users/
> > > >
> > >
> >

> CAGXJAmwQSyYPdPwEGB4SpJ0b28BSwPQK8Z2p81vBaV3FeaRRRw%40mail.gmail.com <http://40mail.gmail.com> <http://40mail.gmail.com <http://40mail.gmail.com>>

> > > <http://40mail.gmail.com <http://40mail.gmail.com>
> <http://40mail.gmail.com <http://40mail.gmail.com>>>

> > > > <https://groups.google.com/d/msgid/cloudlab-users/
> <https://groups.google.com/d/msgid/cloudlab-users/>
> > <https://groups.google.com/d/msgid/cloudlab-users/ <https://

> groups.google.com/d/msgid/cloudlab-users/>> <https://
> > > groups.google.com/d/msgid/cloudlab-users/ <http://
> groups.google.com/d/msgid/cloudlab-users/> <http://
> > groups.google.com/d/msgid/cloudlab-users/ <http://
> groups.google.com/d/msgid/cloudlab-users/>>>
> > > >
> > >
> >

> CAGXJAmwQSyYPdPwEGB4SpJ0b28BSwPQK8Z2p81vBaV3FeaRRRw%40mail.gmail.com <http://40mail.gmail.com> <http://40mail.gmail.com <http://40mail.gmail.com>>

> > > <http://40mail.gmail.com <http://40mail.gmail.com>

> <http://40mail.gmail.com <http://40mail.gmail.com>>>?
> > > > utm_medium=email&utm_source=footer>.
> > >
> > > --
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> users+un...@googlegroups.com <mailto:cloudlab-
> users%2Bunsu...@googlegroups.com>
> > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>>
> > > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>
> > <mailto:cloudlab-users%252Buns...@googlegroups.com
> <mailto:cloudlab-users%25252Bun...@googlegroups.com>>>.
> > > To view this discussion visit https://

> groups.google.com/d/ <https://groups.google.com/d/>

> > msgid/ <https://groups.google.com/d/msgid/ <https://
> groups.google.com/d/msgid/>>

> > > cloudlab-users/2fc7e1e9-7bdf-43de-
> > a824-6d79246a225b%40flux.utah.edu <http://40flux.utah.edu>
> <http://40flux.utah.edu <http://40flux.utah.edu>>
> > > <https://groups.google.com/d/msgid/cloudlab- <https://
> groups.google.com/d/msgid/cloudlab-> <https://
> > groups.google.com/d/msgid/cloudlab- <http://groups.google.com/d/
> msgid/cloudlab->>
> > > users/2fc7e1e9-7bdf-43de-
> a824-6d79246a225b%40flux.utah.edu <http://40flux.utah.edu>

> > <http://40flux.utah.edu <http://40flux.utah.edu>>>.
> > >
> > > --
> > > You received this message because you are subscribed to
> the Google
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> > send
> > > an email to cloudlab-user...@googlegroups.com
> <mailto:cloudlab-users%2Bunsu...@googlegroups.com>
> > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>>
> > > <mailto:cloudlab-user...@googlegroups.com
> <mailto:cloudlab-users%2Bunsu...@googlegroups.com>
> > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>>>.
> > > To view this discussion visit https://groups.google.com/d/
> msgid/ <https://groups.google.com/d/msgid/>
> > <https://groups.google.com/d/msgid/ <https://
> groups.google.com/d/msgid/>>

> > > cloudlab-users/CAGXJAmyG%3DAAcFyQ24aVE7x-6_D13MXNM0eOWWCRD7kF-
> > > %3DgEVhg%40mail.gmail.com <http://40mail.gmail.com>

> <http://40mail.gmail.com <http://40mail.gmail.com>> <https://

> > groups.google.com/d/msgid/cloudlab- <http://groups.google.com/d/
> msgid/cloudlab-> <https://groups.google.com/d/ <https://
> groups.google.com/d/>
> > msgid/cloudlab->
> > > users/CAGXJAmyG%3DAAcFyQ24aVE7x-6_D13MXNM0eOWWCRD7kF-
> > > %3DgEVhg%40mail.gmail.com?
> utm_medium=email&utm_source=footer <http://40mail.gmail.com?

> utm_medium=email&utm_source=footer>
> > <http://40mail.gmail.com?utm_medium=email&utm_source=footer
> <http://40mail.gmail.com?utm_medium=email&utm_source=footer>>>.
> >
> > --
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> > send an email to cloudlab-user...@googlegroups.com

> <mailto:cloudlab-users%2Bunsu...@googlegroups.com>
> > <mailto:cloudlab-users%2Bunsu...@googlegroups.com
> <mailto:cloudlab-users%252Buns...@googlegroups.com>>.
> > To view this discussion visit https://groups.google.com/d/
> msgid/ <https://groups.google.com/d/msgid/>

> > cloudlab-users/5a9ee885-8d49-41de-
> a075-5ea82e64d54a%40flux.utah.edu <http://40flux.utah.edu>

> > <https://groups.google.com/d/msgid/cloudlab- <https://
> groups.google.com/d/msgid/cloudlab->

> > users/5a9ee885-8d49-41de-a075-5ea82e64d54a%40flux.utah.edu

> > cloudlab-users/CAGXJAmz-YxAaK%3DY-%3D8Zu9efajxCLtmSbLV7W5-
> > z55f8Oed0v9w%40mail.gmail.com <http://40mail.gmail.com> <https://
> groups.google.com/d/msgid/ <https://groups.google.com/d/msgid/>
> > cloudlab-users/CAGXJAmz-YxAaK%3DY-%3D8Zu9efajxCLtmSbLV7W5-
> > z55f8Oed0v9w%40mail.gmail.com?utm_medium=email&utm_source=footer

> <http://40mail.gmail.com?utm_medium=email&utm_source=footer>>.
>
> --
> You received this message because you are subscribed to the Google
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> To unsubscribe from this group and stop receiving emails from it,
> send an email to cloudlab-user...@googlegroups.com
> <mailto:cloudlab-users%2Bunsu...@googlegroups.com>.
> To view this discussion visit https://groups.google.com/d/msgid/

> cloudlab-users/5876d9c5-181a-4759-b336-42b2044a1d07%40flux.utah.edu
> <https://groups.google.com/d/msgid/cloudlab-
> users/5876d9c5-181a-4759-b336-42b2044a1d07%40flux.utah.edu>.

> cloudlab-users/CAGXJAmx2S-
> CNzEWkNcT2MLULxUNsmtGxE%3DC8NEkUjEkjvzfnhQ%40mail.gmail.com <https://
> groups.google.com/d/msgid/cloudlab-users/CAGXJAmx2S-
> CNzEWkNcT2MLULxUNsmtGxE%3DC8NEkUjEkjvzfnhQ%40mail.gmail.com?
> utm_medium=email&utm_source=footer>.

John Ousterhout

unread,

Jan 30, 2026, 8:48:50 PMJan 30

to cloudla...@googlegroups.com

I have now successfully booted a 4.18.0 kernel with the UBUNTU 20 image. Thank you for your help!

Now I have a new problem, though. I'd like to save an image with that kernel and various modifications and installed apps, to simplify continued experimentation. However, the 'Create Disk Image' button won't let me do that (presumably because you want to EOL UBUNTU 20). Is there any way for me to get around that?