[PVE-User] container live migration (like OpenVZ)

[Thomas Lamprecht]

Hi,

Am 07.11.25 um 19:02 schrieb Kaonashi:
> OpenVZ, the successor of lxc, had container live migration.

Which only worked for limited setups and use cases.

> CloudLinux with an OpenVZ kernel, still has it I believe.

OpenVZ is EOL since a long time, and it's approach heavily modified
the upstream kernel and made following upstream hard.
We most certainly do not want to add that big known tech debt again
after being able to provide a modern CT stack using native Linux
technology. I could not find anything to CloudLinux and CT
live-migration, albeit the might use Virtuozo kernel (successor
of openVZ), but nowadays that also uses LXC IIRC.

> When will live migration on ProxMox for lxc containers re-appear?

Not anytime soon, and it's not unlikely that this will never come for
LXC. Use VMs when you need live-migration anytime soon.

Background:
Containers are to intertwined with the kernel, and while CRIU tries to
provide a solution for serializing a set of processes (like those of
the CT) to a file and be able to load it again, it's quite limited and
that's not to say the CRIU devs don't try, it's an extremely hard
problem. And that gets even harder due to the kernel continuously
changing, gaining new features and changing how the internal state
looks like for existing ones; i.e., even if one would have answers for
every CRIU problem, it still would need a ton of maintenance work to tag
along.

Virtual machines OTOH have a clear state and memory boundary designed
with these requirement in mind, thus it's relatively (!) easy to do
there

regards,
 Thomas