[openstack-dev] [Heat] in-instance update hooks

Clint Byrum clint at fewbar.com
Tue Feb 11 05:22:54 UTC 2014


Hi, so in the previous thread about rolling updates it became clear that
having in-instance control over updates is a more fundamental idea than
I had previously believed. During an update, Heat does things to servers
that may interrupt the server's purpose, and that may cause it to fail
subsequent things in the graph.

Specifically, in TripleO we have compute nodes that we are managing.
Before rebooting a machine, we want to have a chance to live-migrate
workloads if possible, or evacuate in the simpler case, before the node
is rebooted. Also in the case of a Galera DB where we may even be running
degraded, we want to ensure that we have quorum before proceeding.

I've filed a blueprint for this functionality:

https://blueprints.launchpad.net/heat/+spec/update-hooks

I've cobbled together a spec here, and I would very much welcome
edits/comments/etc:

https://etherpad.openstack.org/p/heat-update-hooks



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