delay a virtual node

[Thanh Do]

hi all,

is it possible to add delay node for a virtual node (i.e., pcvm)? I tried to create an experiment to do so but Emulab keeps giving config error message.

Thanks,

Thanh

[Leigh Stoller]

> is it possible to add delay node for a virtual node (i.e., pcvm)? I tried to create an experiment to do so but Emulab keeps giving config error message.

Hi. See this page:

https://wiki.emulab.net/wiki/linkdelays

The info is a little dated, but the gist is that when you specify
a link that requires shaping, it will be done on your nodes, not as
a separate delay node. If you received an error, then of course you
tell us what experiment it is (if in Utah), the NS file, and what the
error is (send the log). More info the better ...

Lbs

[Thanh Do]

Hi, 

Inline are error messages and the ns file for my experiment (ucare/lights1).

Basically, what I want to do is to create a bunch of virtual nodes and

a few (1-2) physical nodes. Then I tried to shape bandwidth to those

physical nodes using  tb-set-node-lan-bandwidth

Thanks,

Thanh

---- Inline starts here.

*** vtopgen:
    Could not create vtop for [Experiment: ucare/lights1]



--------- /usr/testbed/expwork/ucare/lights1/startexp.O11CaU --------
Running 'tbprerun  -e 138628 lights1.ns'
Beginning pre run for ucare/lights1. 08:43:51:566998
Running parser ... 08:43:51:811832
DISKNAME=disk0-1 DISKTYPE=linear DISKSIZE=8000 MOUNTPOINT=/tmp/disk0
DISKNAME=disk1-1 DISKTYPE=linear DISKSIZE=8000 MOUNTPOINT=/tmp/disk1
DISKNAME=disk0-2 DISKTYPE=linear DISKSIZE=8000 MOUNTPOINT=/tmp/disk0
DISKNAME=disk1-2 DISKTYPE=linear DISKSIZE=8000 MOUNTPOINT=/tmp/disk1
Parser done! 08:44:03:987374
Precomputing visualization ...
Image rendering proceeding in background mode ...
Setting up static routes (if requested) ...
Generating topomap ...
Adding DB 'ucare+lights1' to mysql database on users.emulab.net.
Adding user 'E138628' to mysql database on users.emulab.net.
Verifying parse ...
Doing a pre-assign: '/usr/testbed/bin/vtopgen -p ucare lights1' ...
Checking for feature LibVtopTest.
Using test version of libvtop ...
*** WARNING: vtopgen:
***   lan0: changing node-1:0 to non-encapsulating since physical host does
***   not support veth-ne
*** WARNING: vtopgen:
***   lan0: changing node-2:0 to non-encapsulating since physical host does
***   not support veth-ne
*** WARNING: vtopgen:
***   [vnode:node-2] in lan [vlan:lan0] is running an OSID
***   (FEDORA15-DAGENT-JAVA) that does not support linkdelays (endnode
***   traffic shaping)
*** vtopgen:
    Could not create vtop for [Experiment: ucare/lights1]
Cleaning up after errors.
Killing the renderer.
Removing experiment state.
*** ERROR: tbprerun: assign prerun failed!
*** ERROR: batchexp: tbprerun failed!
Cleaning up and exiting with status 255 ...
Running 'tbend -f -e 138628'
Beginning cleanup for ucare/lights1. 08:44:22:880948
Clearing out virtual state.
Removing visualization data...
Deleting user 'E138628' from mysql database on users.emulab.net.
Removing DB 'ucare+lights1' from mysql database on users.emulab.net.
Cleanup finished! 08:44:26:259263
**** Experimental information, please ignore ****
Session ID = 235206058
Likely Cause of the Problem:
  *** vtopgen:
      Could not create vtop for [Experiment: ucare/lights1]
Cause: internal
Confidence: 0.6
Script: vtopgen
**** End experimental information ****

--------- lights1.ns --------
# This script creates a cluster of virtual nodes.
# We do not create about vdisks for every node as the goal
# is to reproduce interesting network-related cases at scale.
set ns [new Simulator]
source tb_compat.tcl
set maxnodes 60
set lanstr ""

# Create LAN including node from 1 to N
for {set i 1} {$i <= $maxnodes} {incr i} {
    set node($i) [$ns node]
    append lanstr "$node($i) "
    if {$i <= 2} {
       tb-set-node-os $node($i) FEDORA15-DAGENT-JAVA
       tb-set-hardware $node($i) pc3000
       set setup($i) [$node($i) program-agent]
       set createdisk($i) [$ns event-sequence {
           $setup($i) run -command "rm -rf /tmp/disk0"
           $setup($i) run -command "rm -rf /tmp/disk1"
           $setup($i) run -command "mkdir /tmp/disk0"
           $setup($i) run -command "mkdir /tmp/disk1"}]
        $ns at 0.0 "$createdisk($i) start"
        # We still $i here to numbered the disk, as our delaying framework depends on this.
        set disk0($i) [$node($i) disk-agent -type "linear" -mountpoint "/tmp/disk0" -size 8000]
        set disk1($i) [$node($i) disk-agent -type "linear" -mountpoint "/tmp/disk1" -size 8000]
        $ns at 10 "$disk0($i) run"
        $ns at 12 "$disk1($i) run"
    } else {
      tb-set-node-os $node($i) OPENVZ-STD
      tb-set-hardware $node($i) pc3000-vm
    }
}

# Somehow make-cloud does not work with vnodes.
# set lan0 [$ns make-cloud "$lanstr" 100Mb 0ms]
set lan0 [$ns make-lan "$lanstr" 100Mb 0ms]
tb-set-node-lan-bandwidth $node(2) $lan0 50Mb

$ns rtproto Static

# Go!
$ns run

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[Leigh Stoller]

> Inline are error messages and the ns file for my experiment
> (ucare/lights1). Basically, what I want to do is to create a bunch of
> virtual nodes and a few (1-2) physical nodes. Then I tried to shape
> bandwidth to those physical nodes using tb-set-node-lan-bandwidth

Okay, I made a small change to the database descriptor for your image.
This change might be okay, depending on how old the image is.

Also, in your NS file, change:

tb-set-node-os $node($i) OPENVZ-STD

to:

tb-set-node-os $node($i) OPENVZ-STD FEDORA15-OPENVZ-UPD

If it does swapin, be sure to run Link Test (from the Show Experiment web
page) to make sure all the links are working properly.

Lbs

[Thanh Do]

swapped in!

Thanks a lot.

Thanh

Lbs

[Leigh Stoller]

Did ya run link test?  We strongly recommend that you do!

[Thanh Do]

The link test  (level-3) is currently running.

just one more question, in my ns file, I have:

tb-set-node-lan-bandwidth $node(2) $lan0 50Mb

This doesn't create a delay node.

So this end-node shaping right?

Will tevc work in this case?

For example:

tevc -e ucare/lights now lan0-node-2 modify bandwidth=100

[Leigh Stoller]

> This doesn't create a delay node.
> So this end-node shaping right?

Correct.

> Will tevc work in this case?

Sadly, no. We do not have dynamic delays when using end-node
shaping. You can log into your VMs though, cd into /var/emulab/boot,
and find the script that sets up the delays. This will give you
enough info to make changes yourself.

It would be nice to have dynamic delays, but we need someone to
volunteer!

Lbs

[Thanh Do]

Is /var/emulab/boot/ltmap the right file to modify?

and for the traffic shaping to be effective,

I need to modify all the ltmap files on every node/VMs, right?

Lbs

[Thanh Do]

also, after the modification, do i need to reboot all of the nodes?

[Mike Hibler]

ltmap is only used by linktest to check the settings.

In the Experiment Options menu, go to the "Modify Traffic Shaping" link,
make your changes, check the "Save?" box, and hit the Execute button.
This will save the changes to the database. Then reboot the nodes and they
should get statically configured with the new parameters.

[Thanh Do]

oh, I see,

Thanks!