Support load balancer admin state feature #9633
Description
What would you like to be added:
Manually control load balancer admin state to bypass new traffic to broken nodes before health probe fails.
Why is this needed:
We don't want to wait for health probe fails (default 5s * 2 at most) before new traffic can be routed to a broken node. By setting lb admin state to Down, we can bypass the health check logic and block the traffic immediately.