TFS only releasing to the first agent in an environment

Question

In TFS 2015 Update 2, I have configured seven release agents in one pool, separated into a set of logical environments using capabilities.

I also have a release configured with three environments defined to use the queue corresponding to this pool and demands specified to filter to the appropriate servers for each environment (1-Test, 2-QA, 4-Prod).

My problem is that TFS is only releasing to the first agent created that meets the demands. If I remove all demands in an environment I would assume it would release to every agent in the pool yet TFS still releases to only the first agent in the pool. If I disable that first agent, it will release to the next; but still to only one agent.

What am I missing?

Answer 1

I think you're misunderstanding what agents are for. The agent merely acts as an invocation mechanism for your deployment activities. You don't need one agent per environment or per server.

For example, if you need to run a PowerShell script on a machine, you use the "PowerShell on Target Machine" deployment activity. The agent will then use WinRM to tell the target machine what scripts to run. That agent can run PowerShell scripts against any machine.

Answer 2

Why would you want the release or build to select a different agent every time? I had always seen with TFS that the probability of a build running on the agent, where the last successful build for a specific build definition ran, is very high.

The only reason I think a build/release should run on a different agent every time is if the number of builds running at a same time requiring the same capabilities is more than one.

If you would like to test each of the agents then try disabling one agent at a time and run the build/release.