Based on what I gather from the link, the CoreOS Update Strategy is really
a reboot strategy with something pulling updates on a regular basis.

`atomic host upgrade` from cron would serve the same basis as the
"automatic updates" with the potential changes Colin mentioned could
provide another option.

But, like CoreOS, nothing happens until a reboot, and the reboot is the
part that needs the most attention.  There's no mention of how the locking
mechanism works in conjunction with a container orchestration layer like
kubernetes.  How does container rescheduling of a busy node work?  How does
lock acquisition happen?

I think downloading new trees is a fairly simple and trivial problem, but
how do you properly update a cluster of Atomic hosts should involve a
higher level orchestration tool that understand the workloads, the cluster
orchestration, and the host OS issues involved.

- Matt M

On Tue, Sep 29, 2015 at 3:58 PM, Colin Walters <[email protected]> wrote:

> Hi,
>
> On Tue, Sep 29, 2015, at 05:53 AM, Natale Vinto wrote:
> >
> > This let containers hosts being updated silently by pushing the update
> > remotely (solicitate an upgrade) and perform a reboot based some
> > strategies, where the most useful is the one that let the cluster of
> > hosts decide itself what system to reboot, thanks to a lock in the
> > etcd distribuited key-value store, that ensure rebooting only not busy
> > container hosts.
>
> We recently landed a "daemon" mode for rpm-ostree which should
> help implement higher-level logic around host updates.  I'd like
> to integrate a default "timer" option soon.
>
> That said, what I think we really want here is for Kubernetes
> to be in charge of scheduling host updates.  It could
> move pods *before* rebooting a host to ensure that there's
> no downtime.
>
>

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