[ClusterLabs] Resources wont start on new node unless it is the only active node

[Ryan Anstey]

I had a feeling it was something to do with that. It was confusing because
I could use the move command to move between my three original hosts, just
not the fourth. Then there was the device not found errors which added to
the confusion.

I have the resource stickiness set because I have critical things running
that I don't want to move around (such as a windows kvm) and I'd rather not
see any downtime from the reboots. (It tries to actually migrate kvm's but
it doesn't work, lxc vm's are stopped and started.)

I moved them to specific servers because I thought I could do a better job
at balancing the cluster on my own (based on knowing what my VM's were
capable of). I'm not sure if my methods are a good idea or not, just
sounded right to me at the time.

On Tue, Nov 8, 2016 at 2:00 PM Ken Gaillot <kgaillot at redhat.com> wrote:

> On 11/08/2016 12:54 PM, Ryan Anstey wrote:
> > I've been running a ceph cluster with pacemaker for a few months now.
> > Everything has been working normally, but when I added a fourth node it
> > won't work like the others, even though their OS is the same and the
> > configs are all synced via salt. I also don't understand pacemaker that
> > well since I followed a guide for it. If anyone could steer me in the
> > right direction I would greatly appreciate it. Thank you!
> >
> > - My resources only start if the new node is the only active node.
> > - Once started on new node, if they are moved back to one of the
> > original nodes, it won't go back to the new one.
> > - My resources work 100% if I start them manually (without pacemaker).
> > - (In the logs/configs below, my resources are named "unifi",
> > "rbd_unifi" being the main one that's not working.)
>
> The key is all the location constraints starting with "cli-" in your
> configuration. Such constraints were added automatically by command-line
> tools, rather than added by you explicitly.
>
> For example, Pacemaker has no concept of "moving" a resource. It places
> all resources where they can best run, as specified by the
> configuration. So, to move a resource, command-line tools add a location
> constraint making the resource prefer a different node.
>
> The downside is that the preference doesn't automatically go away. The
> resource will continue to prefer the other node until you explicitly
> remove the constraint.
>
> Command-line tools that add such constraints generally provide some way
> to clear them. If you clear all those constraints, resources will again
> be placed on any node equally.
>
> Separately, you also have a default resource stickiness of 100. That
> means that even after you remove the constraints, resources that are
> already running will tend to stay where they are. But if you stop and
> start a resource, or add a new resource, it could start on a different
> node.
>
> <snip>
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