Comment 5 for bug 1473517

Ian, thank you for the comments and instructions. I was able to upgrade my test environment from 1.18 to 1.24.2 with your explanation. I did need to save agent.conf files as some of them were missing apiserver entry (that happened from 1.18 to 1.20 and then from 1.20 to 1.21).
From there I restarted jujud on bootstrap node, and I ended up with usable 1.24.2 environment.

I will test the upgrade of the OpenStack deploy, which will mimic what my customer has. I'll report back here if I run into troubles.