[openstack-dev] [nova] How to debug no valid host failures with placement

Chris Friesen chris.friesen at windriver.com
Thu Aug 2 20:04:10 UTC 2018


On 08/02/2018 01:04 PM, melanie witt wrote:

> The problem is an infamous one, which is, your users are trying to boot
> instances and they get "No Valid Host" and an instance in ERROR state. They
> contact support, and now support is trying to determine why NoValidHost
> happened. In the past, they would turn on DEBUG log level on the nova-scheduler,
> try another request, and take a look at the scheduler logs.

At a previous Summit[1] there were some operators that said they just always ran 
nova-scheduler with debug logging enabled in order to deal with this issue, but 
that it was a pain to isolate the useful logs from the not-useful ones.

Chris


[1] in a discussion related to 
https://blueprints.launchpad.net/nova/+spec/improve-sched-logging



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