Add autoscaler instance_ready_command option
What does this MR do?
Add a new instance_ready_command config option.
The command specified will be executed via SSH/WinRM to ensure that the instance is ready to accept jobs.
What's the best way to test this MR?
There's an integration test added to test this.
However, currently disabled is the test where the instance ready command returns a non-zero exit code.
This scenario doesn't yet "terminate", as in the background, taskscaler will keep trying to create an instance for the job indefinitely. This highlights a problem we have that will be resolved with #37497 (closed) and a backoff.
What are the relevant issue numbers?
Closes #37199 (closed)
Edited by Arran Walker