Implementing Juju Actions

[Gustavo Niemeyer]

On Thu, Mar 27, 2014 at 6:53 AM, Tim Penhey <tim.penhey at canonical.com> wrote:
> The api-server component of juju run does indeed ssh to the units or
> machines to run the commands.  This is done in parallel, and has a max
> timeout value that is configurable.

That's surprising, FWIW.  But that's a separate issue.

> The outline that Gustavo has given has actions fit into this world view.

Indeed. Because that's the way that sounds reasonable, but I'm open to
arguments about why that's not the case.

> A key missing bit here is who is the target of the action?
> Is it a service? Or a unit of the service?

Either. By the end of the day it will be run in a unit.

> If we are looking at actions like "backup database", then I'd guess that
> the target is the service, but do we care which unit does the actual
> backing up?  What about when an action requires synchronisation across
> different services?  Where does the action live?

It's the same problem of internal service coordination. A leader must
be elected to take responsibility for procedures on behalf of the
service.


gustavo @ http://niemeyer.net