Capability to change the GitOps branch for the agent offline

Hi,

While we are preparing a deployment mechanism for the Instana agent in an air-gapped environment we noticed that it is not possible to change the branch name with offline capabilites. Once it is initially set via the INSTANA_GIT_REMOTE_BRANCH environment variable, this variable can no longer to be used to change this value. This can only be changed via the UI or the REST API.

In our case this is not possible as the agent will pull the backend config from the internal GitHub system before connecting for the first time. Now it happened that the branch name was set incorrectly in our deployment package due to a typo and therefore it never connected to the backend. Trying to to correct this value through the evironment variable is not possible (and not documented that this doesn't work) until one deletes the "/instana-agent/etc/.git" directory before trying it again.

In production systems this manual intervention is not possible within our organisation (banking) and potentially also not feasible (hundreds of agents) hence when for example the branchname is changed in the repo and a deployment process is started with the old value it leaves the agent installation bricked on the target systems.

As all the agent configuration is handled locally via YAML and CFG files this crucial piece of configuration should also have an offline capability potentially safeguarded by some keys to avoid inadvertant misconfiguration - e.g. a trigger set when the agent was connected successfully to a backend or a INSTANA-GIT_REMOTE_FORCEBRANCH variable.

At least document the intented behaviour as it is at the moment to spare the customer hours of debugging until they stumble over the .git directory and the unchanged values in there.

Many thanks and regards,

Rainer