[ops] nova wsgi config

Arnaud Morin arnaud.morin at gmail.com
Thu Feb 27 10:06:21 UTC 2020

Hey all,

I am back to this nova processes/threads configuration.
Here is what I have in my apache wsgi config:
$ grep WSGIDaemonProcess /etc/apache2/sites-enabled/10-nova-api.conf
  WSGIDaemonProcess nova-api display-name=nova-api group=nova processes=1 python-home=/opt/openstack/nova python-path=/opt/openstack/nova/ threads=1 user=nova

As you can see, I set 1 process, and 1 thread.

But here is the result after restarting apache:

$ ps -ef | grep nova
nova      8535  8527  4 09:10 ?        00:02:15 nova-api          -k start

$ ps -o pid -o thcount -p8535
 8535     4

So, nova-api is running 4 threads!

I am running nova stein.

I checked in nova code but I am far from beeing an expert on the subjet,
so does anyone can give me a clue on why nova is doing threading, while
it should not?

Thanks in advance,

Arnaud Morin

On 25.10.19 - 01:15, Thomas Goirand wrote:
> On 10/24/19 11:06 AM, Arnaud Morin wrote:
> > Hey Thomas,
> > 
> > Thank you for your example.
> > If I understand well, you are using 4 processes in the uwsgi config.
> > I dont see any number of thread, does it mean the uwsgi is not spawning
> > threads but only processes? ( so there is only 1 thread per process?)
> > 
> > Thanks,
> Hi Arnaud,
> If you carefully read the notes for nova, they are saying that we should
> leave the number of thread to 1, otherwise there may be some eventlet
> reconnection to rabbit issues.
> It's however fine to increase the number of processes.
> Cheers,
> Thomas Goirand (zigo)

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