I have installed Openstack Ussuri and Wallaby (two different VMs) using devstack on Ubuntu 18.04 and 20.04 machines (more than one). I'm capable of spawning instances (using openstack server create) and all is good. However, I wish to see the logs of the system, which suppose to be at /var/logs/<service_name> (according to this official doc). However, I have no such directories at all, even after getting an error on instance spawning.
I have checked, and at the nova.conf I have: debug = True, I do get the logs from the RabbitMQ, OpenVSwitch and so on, but not from any of the openstack services.
I even searched my entire filesystem for a file that contains nova and log and there is nothing.
You can still configure the services to log to a file, but keep in mind that you need to rotate the logs otherwise they will eventually fill up the disk.
To enable logs just add log_file under the [DEFAULT] section of the service configuration (e.g. /etc/nova/nova.conf).
[DEFAULT]
log_file = /opt/stack/logs/nova.log
The configuration options are documented here.
You could also just read logs directly from journal, there are a bunch of libraries to assist with this. A better alternative is probably to have journald forward the logs to another service (e.g. rsyslog, splunk) and use those for your post processing.