Implement system reboot via juju hooks

[Stuart Bishop]

On 8 August 2014 19:58, Gabriel Samfira <gsamfira at cloudbasesolutions.com> wrote:
> Hello folks!
>
> I would like to start work on implementing reboots via juju hooks. I
> have outlined in a google docs document a few thoughts regarding why
> this is needed and some implementation details I would like to discuss
> before starting.
>
> You may find the doc here:
>
> http://goo.gl/tGoIuM
>
> Any thoughts/suggestions are welcome.
>
> Gabriel

I don't think this should be restricted to server reboots. The
framework is generally useful.

I have hooks that need to bounce the primary service so config changes
can take effect. They can't do that if a long running operation is
currently in progress, eg. a backup or a replica node is being built.
Currently, I need to block the hook until such time as I can proceed.
I think this would be cleaner if I could instead return a particular
error code from my hook, stating that it is partially complete and
requesting it to be rescheduled.

So it would be nice if requesting a reboot and requesting a hook to be
rescheduled are independent things.

I had wondered if juju-run should allow arbitrary things to be run in
a hook context later.

juju-run --after hook /sbin/reboot # queue the reboot command to be
run after this hook completes.
juju-run --after hook config-changed  # queue the config-changed hook
to be run after this hook completes, and after any previously queued
commands
juju-run --after tomorrow report-status # Run the report-status
command sometime after 24 hours.

-- 
Stuart Bishop <stuart.bishop at canonical.com>