On Mon, 7 Dec 2020 at 18:25, Nicolas Parquet <nicolas.parquet@gandi.net> wrote:

Hello Ironic people!

I am coming to you with a question from one of the points we discussed during Masakari's PTG [1].

When a host fails and Masakari gets notified, there are some cases in which we would like Masakari to power fence the host before evacuating its instances to other hosts. That way it is safe to start the instances from the failed host on another one.

Given that Ironic has the responsability of managing hosts, we would be interested to know how Masakari should do that, in your view? We discussed implementing IPMI power on / off directly in masakari, but maybe an integration where Masakari calls some Ironic API would be better? Or maybe we should implement it relying on the pyghmi library, or any other library?

A positive side of relying on Ironic would be that Masakari does not have to store IPMI information about hosts; however that would create a dependency between the 2 projects as some deployments might use masakari without managing their hosts through Ironic.

Any insight is welcome!

Hi Nicolas, I would suggest defining a power management plugin interface, with the first implementation being for Ironic. If in future someone wants to add support for MAAS, IPMI, or any other tool, it should be possible. Any per-host configuration would need to be extensible enough to support this.

Regards, Nicolas

[1] https://etherpad.opendev.org/p/masakari-wallaby-vptg

-- Nicolas Parquet Gandi nicolas.parquet@gandi.net