Open Stack

This is also a use case for Congress, please check use case 3 in the
following link.

https://docs.google.com/document/d/1ExDmT06vDZjzOPePYBqojMRfXodvsk0R8nRkX-zrkSw/edit#

2014-10-14 5:59 GMT+08:00 Russell Bryant <rbryant at redhat.com>:

> Nice timing.  I was working on a blog post on this topic.
>
> On 10/13/2014 05:40 PM, Fei Long Wang wrote:
> > I think Adam is talking about this bp:
> >
> https://blueprints.launchpad.net/nova/+spec/evacuate-instance-automatically
> >
> > For now, we're using Nagios probe/event to trigger the Nova evacuate
> > command, but I think it's possible to do that in Nova if we can find a
> > good way to define the trigger policy.
>
> I actually think that's the right way to do it.  There are a couple of
> other things to consider:
>
> 1) An ideal solution also includes fencing.  When you evacuate, you want
> to make sure you've fenced the original compute node.  You need to make
> absolutely sure that the same VM can't be running more than once,
> especially when the disks are backed by shared storage.
>
> Because of the fencing requirement, another option would be to use
> Pacemaker to orchestrate this whole thing.  Historically Pacemaker
> hasn't been suitable to scale to the number of compute nodes an
> OpenStack deployment might have, but Pacemaker has a new feature called
> pacemaker_remote [1] that may be suitable.
>
> 2) Looking forward, there is a lot of demand for doing this on a per
> instance basis.  We should decide on a best practice for allowing end
> users to indicate whether they would like their VMs automatically
> rescued by the infrastructure, or just left down in the case of a
> failure.  It could be as simple as a special tag set on an instance [2].
>
> [1]
>
> http://clusterlabs.org/doc/en-US/Pacemaker/1.1/html-single/Pacemaker_Remote/
> [2] https://review.openstack.org/#/c/127281/
>
> --
> Russell Bryant
>
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>



-- 
Thanks,

Jay
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