On 5 September 2016 at 04:15, Andy Smith <andy@???> wrote:
> On Thu, Aug 25, 2016 at 09:11:51PM +0000, Andy Smith wrote:
> > By now you should have all received notification of the scheduled
> > maintenance that will be taking place in the early hours of the
> > morning (UK time) on 2016-09-02, 03 and 05.
>
> Today's maintenance is now completed and went without incident.
> Thanks for your patience in this matter. It is unfortunate that we
> have had two serious security issues come to light within 6 weeks of
> each other.
>
> As mentioned in previous similar events, when we have to reboot a
> host we prefer to have all customer VPSes shut down and then boot
> again.
>
> Xen and Linux do contain support for suspend and restore, so in
> theory it would be possible to suspend customer VPSes to storage and
> then restore them again when the host has been booted. To the VPS
> and processes inside it this would look like time stood still.
> Network connections would most likely drop.
>
> Although this is much less disruptive than a shutdown and boot, it
> doesn't always work. Some older Linux kernels don't restore
> correctly, leaving the VPS in a hung state (requires destroy and
> boot again).
>
> Some applications get massively confused by the clock getting stuck.
> I have experienced that with pacemaker (clustering software); I
> could not get the restored node to rejoin the cluster without
> stopping the cluster on every node and starting it again, which was
> much more more disruptive than just rebooting the VPS would have
> been, given it was in an HA cluster anyway!
This sounds like it *might* be a Pacemaker bug, or (more likely)
potentially a worthwhile enhancement; I suggest that you send a mail
to the mailing list describing the use case:
http://clusterlabs.org/mailman/listinfo/users
They might say "sorry, we can't support that", or who knows, they
might say "nice idea, thanks!" Either way, I know several of the
Pacemaker folks and can promise that they are super friendly and
helpful :-)
