Is systemd v219 sufficient to run rkt 1.27.0?

[Mark Petrovic]

I read here https://coreos.com/rkt/docs/latest/dependencies.html#run-time-dependencies that systemd version >= 222 is a runtime dependency of rkt.  However, I find that a sample container of interest apparently runs fine under systemd v219 (CentOS7).  I'm only interesting in running containers with rkt, not in building rkt itself.  Upgrading our systems to systemd v222 for purposes of running rkt would be a tough sell in my organization.  

Is systemd v219 sufficient to run containers with rkt?

Thank you.

[Luca BRUNO]

On Friday, July 7, 2017 3:21:27 PM UTC Mark Petrovic wrote:
> I read here
> https://coreos.com/rkt/docs/latest/dependencies.html#run-time-dependencies
> that systemd version >= 222 is a runtime dependency of rkt.

That specific section is about stage1 host flavor, which is mostly only useful
for developer and distro maintainers. Production users typically use
stage1-coreos, which doesn't have such restriction.

> Is systemd v219 sufficient to run containers with rkt?

In general, it *may* be enough. rkt has few requirements on the environment
(kernel + userland setup), and recent enough OS should be fine if you don't
plan to use advanced rkt features (socket activation, notification, etc.).

That said, v219 is quite ancient and you may encounter some subtle
incompatibilities and hit some implicit assumptions which aren't satisfied on
such ancient OS. I guess the same will hold for the kernel.

I would recommend to run a fresher OS if possible, or otherwise just try your
rkt workloads and report any issues to the bug tracker.

Ciao, Luca

--
"If you build a wall, think of what you leave outside it" - Italo Calvino