[Victoria] /var/run/octavia empty

After deploying the charm or changing config on the charm /var/run/octavia has no files in it. API calls then time out with the following message in the apache2 log;

octavia_lib.api.drivers.exceptions.DriverAgentNotFound: Unable to open the driver agent socket: /var/run/octavia/status.sock

systemctl reports that octavia-driver-agent is running. The log file /var/log/octavia/octavia-driver-agent.log has no errors. But the files are missing.

If I restart the octavia-driver-agent.service manually or reboot the machine the files are created. If I change charm configuration the problem reappears.

$ juju ssh octavia/0 -- sudo ls -l /var/run/octavia
total 0

$ juju ssh octavia/0 -- sudo systemctl restart octavia-driver-agent.service

$ juju ssh octavia/0 -- sudo ls -l /var/run/octavia
total 0
srwxr-xr-x 1 octavia octavia 0 Jun 11 17:42 get.sock
srwxr-xr-x 1 octavia octavia 0 Jun 11 17:42 stats.sock
srwxr-xr-x 1 octavia octavia 0 Jun 11 17:42 status.sock

$ juju ssh octavia/0 -- sudo reboot
Connection to 10.23.130.41 closed by remote host.

$ juju ssh octavia/0 -- sudo ls -l /var/run/octavia
total 0
srwxr-xr-x 1 octavia octavia 0 Jun 11 17:42 get.sock
srwxr-xr-x 1 octavia octavia 0 Jun 11 17:42 stats.sock
srwxr-xr-x 1 octavia octavia 0 Jun 11 17:42 status.sock

$ juju config octavia spare-pool-size=1

$ juju ssh octavia/0 -- sudo ls -l /var/run/octavia
total 0