teamcity on demand agents and patching windows

TeamCity On Demand / Cloud agents enable you to reduce build costs by shutting down instances when not in use, as well as freeing up costly TeamCity licenses for other agents.

After implementing TeamCity On Demand agents we have seen a significant reduction in build agent hosting costs, as they are now only being started when needed and then automatically being shut down once the build has completed.

Additionally, since our teams are around the world, we can use a lower number of TeamCity licenses than we have agents available for teams. Licenses are automatically assigned to agents only when they are running.

This allows us to spin down the agents of teams which won't be actively building at the time, with the ability to automatically spin up agents to accomodate the late-night coder on the other side of the world.

However one issue that must be kept in mind with On Demand agents is scheduled patching windows.

We have scheduled patching on a weekly basis, and since the On Demand agents were often stopped during these patch windows, I would come in the next morning to a notification of hundreds of servers which I had to do follow up patches for.

To resolve this, I created a script which automatically starts all TeamCity On Demand agents and keeps them running through the patching window, and then stops them after the patches have completed.

While I unfortunately cannot share this script, I can share some some caveats I found along the way. This should help if you plan on writing a similar script of your own.

last updated 2019-02-18T15:56:19+0000