We want to replace the existing 4.7.2 console server (which is connected to 4.7.2 agents), with a new console server at version 5.6.1.
We plan to install new server, stop the old one, and start the new one.
There will be a period of time that the agents version would be 4.7.2 and the console will be 5.6.1.
We have couple of questions regarding the upgrade process.
1. Will it cause any issues running like that? We tested 4.7.2 agent with 5.6.1 console, and it seemed to work fine.
2. We have a system that uses GLU APIs.
Were there major changes in the GLU API? or we could expect that the 4.7.2 APIs will also work on 5.6.1?
3. I didn't managed to fully understand the GLU <-> Zookeeper connection.
Replacing the console server can reflect somehow on the agent's state in the zookeeper?
Or the state is managed only by the agents themselves, and replacing the console shouldn't be an issue for the states?
You are jumping a lot of releases and although it should work there are a couple of things that have changed so you should make sure you are not using them (ex: the console.systemModelRenderer.maintainBackwardCompatibilityInSystemId flag, or agentZooKeeper variale in glu script, etc...)
To answer your questions:
1. I believe it should work and you should definitely take it slow. I would recommend backing up the console database. Then switching the console to 5.6.1. If everything works, then switch 1 agent to 5.6.1. If it works then switch 2 agents, etc... until you are confident and can switch everything
2. No there are not been major changes. Only a couple of features were added and it is backward compatible. But definitely run some tests before you go full blown
3. The console is only reading the state in ZooKeeper. So changing the console has no effect for ZooKeeper. Every time you stop/start and agent it will write its state to ZooKeeper and the console will pick it up.
Note that you should be able to use the agent upgrade feature built in the console...