Computer with two CoreOS-installed disks mounts its filesystems from both, at random

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Rob Roy Gregg

Mar 26, 2020, 1:43:18 PM3/26/20
to CoreOS User
CoreOS Container Linux fans,

I have a computer with two disks, both of which are installed with CoreOS Container Linux 2345.3.0.

After booting, I can see that some content's mounted from the first disk, and some from the second, like this:

core@robroy-lx3 ~ $ mount | grep sd
/dev/sdb9 on / type ext4 (rw,relatime,seclabel)
/dev/sdb6 on /usr/share/oem type ext4 (rw,nodev,relatime,seclabel)
/dev/sda1 on /boot type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,errors=remount-ro)

My goal's to have CoreOS use only the disk it booted from, and ignore the other disk, so that (given that I booted from sda) the output would look like this every time:

core@robroy-lx3 ~ $ mount | grep sd
/dev/sda9 on / type ext4 (rw,relatime,seclabel)
/dev/sda6 on /usr/share/oem type ext4 (rw,nodev,relatime,seclabel)
/dev/sda1 on /boot type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,errors=remount-ro)

Rebooting the computer several times shows that CoreOS chooses which disk to mount its filesystems from at random; sometimes /boot's mounted from sda, other times sdb.

I tried this in my Ignition file to confine CoreOS to only one disk, yet it made no difference:

"storage": {
  "disks": [{"device": "/dev/sda"}]

Thank you very much!

Rob Roy

Benjamin Gilbert

Mar 26, 2020, 8:28:01 PM3/26/20
to Rob Roy Gregg, CoreOS User
That's not surprising.  Container Linux mounts its filesystems by label, and there shouldn't be multiple filesystems with the same label on a machine.  The solution is not to do that.  :-)

Note that CoreOS Container Linux will reach its end of life on May 26 and will not receive updates after that date.

--Benjamin Gilbert

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Rob Roy Gregg

Mar 27, 2020, 1:32:18 PM3/27/20
to CoreOS User
Thank you Benjamin!
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