[Users] CentOS 7.2 Upgrade with OpenVZ container and 2.6 kernel

[Scott Dowdle]

Greetings,

----- Original Message -----
> We rent a CentOS 7.1 VM:
> 
>     $ cat /etc/redhat-release
>     CentOS Linux release 7.1.1503 (Core)
> 
> CentOS 7.2 was released recently
> (http://wiki.centos.org/Manuals/ReleaseNotes/CentOS7) and yum is
> prompting us to upgrade. In addition, its not giving us 7.1 security
> updates.
> 
> We want to upgrade, but we are not sure if our configuration is
> tested. The configuration includes a 2.6 kernel (not a 3.x kernel),
> and we believe is due to OpenVZ container
> (http://unix.stackexchange.com/q/238317):
> 
>     $ uname -a
>     Linux cryptopp 2.6.32-042stab112.15 #1 SMP Tue Oct 20 17:22:56 \
>         MSK 2015 x86_64 x86_64 x86_64 GNU
> 
> We can't determine if this a supported configuration, so we are not
> sure if its expected to upgrade. The release notes don't discuss it
> (http://wiki.centos.org/Manuals/ReleaseNotes/CentOS7), and we could
> not find information on it searching the list archives
> (http://www.google.com/search?q="CentOS+7.2"+site:lists.openvz.org).
> 
> Is it safe to perform the upgrade from 7.1 to 7.2 with the 2.6
> kernel?
> That is, is this a supported configuration that will update as
> expected? If not, then what are our options?

The current stable OpenVZ release is called OpenVZ Legacy and it is based on a RHEL6-based OpenVZ kernel branch.  All containers on that host node share the same kernel... so no matter what distro they are running, you'll see that same kernel... so your situation is completely normal.  Chances are, unless it got dragged in for dependencies, you don't even have a kernel package installed inside of your container.

rpm -q kernel

Now having said all of that, I did personally run into a few upgrades from 7.1 to 7.2 where yum just got stuck in the middle of the upgrade... but hopefully that isn't very easy to reproduce... but as always... you should definitely consider doing a backup before any upgrade in the unlikely event that something goes horribly wrong during the upgrade.  I've been using OpenVZ since 2005 and have upgraded a zillion EL4, EL5, EL6, and EL7 (EL = Red Hat Enterprise Linux and clone) minor releases in that time and have very rarely run into an issue... but they always say make a backup before any major changes.

So far as CentOS not addressing it in their release notes, why should they?  They mostly pretend OpenVZ doesn't exist although they do seem fairly Docker friendly these days.

TYL,
-- 
Scott Dowdle
704 Church Street
Belgrade, MT 59714
(406)388-0827 [home]
(406)994-3931 [work]