Open Stack

On Mon, Nov 11, 2013 at 11:34:10AM +0000, Day, Phil wrote:
> Hi Folks,
> 
> I'd like to get some eyes on a bug I just filed:  https://bugs.launchpad.net/nova/+bug/1250049
> 
> A recent change (https://review.openstack.org/#/c/52189/9 ) introduced the automatic disable / re-enable of nova-compute when connection to libvirt is lost and recovered.   The problem is that it doesn't take any account of the fact that a cloud administrator may have other reasons for disabling a service, and always put nova-compute back into an enabled state.
> 
> The impact of this is pretty big for us - at any point in time we have a number of servers disabled for various operational reasons, and there are times when we need to restart libvirt as part of a deployment.  With this change in place all of those hosts are returned to an enabled state, and the reason that they were disabled is lost.
> 
> While I like the concept that an error condition like this should disable the host from a scheduling perspective, I think it needs to be implemented as an additional form of disablement (i.e a separate value kept in the ServiceGroup API), not an override of the current one.
> 
> I'd like to propose that the current change is reverted as a priority, and a new approach then submitted as a second step that works alongside the current enable /disable reason.
> 
> Sorry for not catching this in the review stage - I didn't notice this one at all.

It seems like it would be pretty easy to just use an explicit 'disable_reason'
string value, and then only automatically re-enable if the string matches the
one we set when disabling it originally. I think that should be easy enough for
someone to do without needing to revert the entire original change.

Daniel
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