Changing branch used by Flux deployment

If the need arises to change the branch used by a Flux installation, this can be done without bootstrapping the cluster again. Not that this is recommended only on similar setups (e.g. you’re trying out a new change on a dev cluster and want to point to your dev branch which is based on the default branch).

Components

This article assumes the following components are in play:

• Kubernetes cluster called cluster01
• Flux mono repo with the cluster definition in the locations clusters/development (this folder contains the flux-system folder)
• A default branch called main
• A working branch called 12345-something-to-test that is based on main with a new change in it

Process

1. Switch to your working branch
2. Run the following command at a shell prompt (Bash, PowerShell, etc…) when the current context is you the target cluster:
   flux suspend source git flux-system
3. Update clusters/development/flux-system/gotk-sync.yaml to set the value of branch to 12345-something-to-test and commit and push it
4. Within your Kubernetes cluster, update the resource of type GitRepository named flux-system in the flux-system namespace so the branch field is also 12345-something-to-test
5. Run the following command at a shell prompt (Bash, PowerShell, etc…) when the current context is you the target cluster:
   flux resume source git flux-system

Once testing is complete, repeat the above process but setting the branch back to main.