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 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.
 in a discussion related to
OpenStack Development Mailing List (not for usage questions)