The build messages processor as well as the main TeamCity server can be stopped or restarted while builds are running there. If agents can't connect to the build messages processor for some time, they will re-route their data to the main server. If the main server is also unavailable, agents will keep their data and re-send it once servers re-appear.
Upgrade & Downgrade
Both the main TeamCity server and the build messages processor must be of exactly the same version.
The upgrade sequence is the following:
- stop build messages processor (if you forget doing that, you'll be warned during upgrade)
- start upgrade on the main TeamCity server as usual
- at some point you will be warned that there is a build messages processor running and using the same database; you'll need to shutdown it first
- proceed with upgrade
- make sure check everything is ok, agents are connecting etc. (since the messages processor is not available anymore, the agents will re-route their data to the main server)
- upgrade software on the messages processor machine to the same version
- start messages processor and check that it is connected via Nodes configuration page on the main server
In order to downgrade you need to:
- shutdown main server and build messages processor
- restore data from backup (only if data format has been changed during upgrade)
- downgrade TeamCity software on the main server
- start the main TeamCity server and check everything works
- downgrade TeamCity software on the build messages processor to the same version as the main server
- start the build messages processor
As usually with TeamCity, agents perform upgrade / downgrade automatically.
- Only one build messages processor can be configured for the main TeamCity server.
- At the moment the build messages processor node does not support plugins.