[Maas-devel] RFC: "Serialising" power actions

[Julian Edwards]

On Wednesday 17 Sep 2014 09:16:38 David Britton wrote:
> My biggest concern as a heavy user of maas is that it actually does what
> it thinks it did.  That is, if I tell maas to power it off, it issues
> the power off command and then checks (to the best of its ability) that
> the machine is powered off before sticking it back in the pool (or
> carrying out the next action).

I agree.

> This discussion seemes to be going down another route though:
> 
> If it's in the pool and I go to the machine in the lab and flip it on
> real quick, I would be surprised that maas shuts it off since it thinks
> it knows best.  If another user acquires it while I'm doing maintence,
> well I'm kind of getting what I deserve there.  This is not the failure
> mode of any of the issues I have hit with MAAS though.  Seems like maybe
> a feature that no one has asked for?

I think you're maybe misunderstanding the MAAS philosophy.  MAAS owns the 
machine, and if you want to do maintenance on it you need to take it out of 
rotation, at which point MAAS won't care what you want do with it, until it's 
marked available again.

So it's not a feature, it's a core principle.

> IOW: Ensuring actions are carried out is different than ensuring state
> is synchronized at all times.  The first problem is a real bug for maas
> right now that hopefully you all are on top of.  The second seems more
> like very unexepected new territory.