Open Stack

On Thu, Jul 28, 2016 at 2:34 PM, Ken D'Ambrosio <ken at jots.org> wrote:
> Trying to orchestrate a bunch of VMs on our ~500 core cloud, and we're
> getting the "not enough hosts" problem.  Only issue is that the dashboard
> seems to imply we've got the elbow room needed to instantiate.  Furthermore,
> it would be *really handy* if I knew what the bottleneck it thought was:
> disk, RAM, CPU, whatever.  Here's a sample of the error:
>
> ----------------------- begin -----------------------
> 2016-07-28 18:40:47.961 1080 WARNING nova.scheduler.utils
> [req-977badf4-a4a2-4766-87fd-c4e3ceb2e293 a4c895a6fe294ae3a81e3c6bb9209f52
> 33c2cf3cb61c425abcb0e0d35fdf21b7 - - -] [instance:
> ee175a40-11d9-4a43-b6e1-c4d7935acff1] Setting instance to ERROR state.
> 2016-07-28 18:40:51.892 1023 WARNING nova.scheduler.utils
> [req-e2a65200-1662-4cd7-aa9e-db5e225adfa1 a4c895a6fe294ae3a81e3c6bb9209f52
> 33c2cf3cb61c425abcb0e0d35fdf21b7 - - -] Failed to
> compute_task_build_instances: No valid host was found. There are not enough
> hosts available.
> Traceback (most recent call last):
>
>   File "/usr/lib/python2.7/dist-packages/oslo_messaging/rpc/server.py", line
> 142, in inner
>     return func(*args, **kwargs)
>
>   File "/usr/lib/python2.7/dist-packages/nova/scheduler/manager.py", line
> 84, in select_destinations
>     filter_properties)
>
>   File
> "/usr/lib/python2.7/dist-packages/nova/scheduler/filter_scheduler.py", line
> 90, in select_destinations
>     raise exception.NoValidHost(reason=reason)
>
> NoValidHost: No valid host was found. There are not enough hosts available.
> ----------------------- begin -----------------------
>
> Any suggestions on how to track down exactly what's going wrong?

Try taking a look at nova-scheduler log on your controller (usually in
/var/log/nova/nova-scheduler.log). I do not remember any time I have
seen the "not enough hosts" when the reason was not obvious from the
scheduler log.

>
> Thanks!
>
> -Ken
>
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---
Mikhail Medvedev
IBM