Why CoreOS may occasionally switch to old version after reboot?

[she...@36kr.com]

Dear all,

   I found a very weird behavior. When I upgraded CoreOS from 607 to 695, the login message said:

Last login: Sun Jun 21 23:03:13 2015 from ***

CoreOS beta (695.2.0) reboot 

But after re-config it (eg: create user, change hostname, etc), it may reboot downgrade to 609, so I lost all my work.

Could you tell me how to see the boot log and volume switching log? I think it is due to some error occurred in booting process.

Or, is there any way to fix booting volume? Just stop at the failure point that I can debug.

--

ShenLei

[Alex Crawford]

On 06/21, she...@36kr.com wrote:
> But after re-config it (eg: create user, change hostname, etc), it may
> reboot downgrade to 609, so I lost all my work.

When CoreOS upgrades (or downgrades) itself, it only touches /usr which
is read-only. What do you mean when you say you "lost all [your] work"?
If you are actually losing work, there is a big problem.

> Could you tell me how to see the boot log and volume switching log? I think
> it is due to some error occurred in booting process.

`journalctl --boot 1` will show you the previous boot. Keep in mind that
the boot is only marked successful about 10 minutes after boot. If you
reboot before it is marked successful, CoreOS will fall back to the
previous version.

-Alex

[Michael Marineau]

Correction: it is marked successful 45 seconds after boot.

[沈雷]

Thank you for your tip  `journalctl --boot 1`.  

Yep, the lost work is not /home, so it is not so serious. Besides /usr, /etc/hostname is also reverted.

--

ShenLei

--

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