GCE load balancer health check vs Instance Groups health check

Question

I am confused by the Google Compute Engine health check. There is one health check on the load balancing level and there is another in the instance groups. What are the differences among the two? can i run both or one at a time?

Answer 1

You're right, there are several purposes for the Health Checks:

• for Load Balancing it is to determine if a node in a LB pool is healthy and ready to handle new connections. HTTP LB requires health checks, while Network LB - doesn't.

• for Instance Groups it is to determine if an Instance Groups has minimum required number of healthy instances. Health Checks are required to perform Autohealing (replacing instances which went bad) or Autoscaling.

You can run both types or none, it really depends on your requirements. It is reasonable to run both, just keep your architecture simple and do not try to use all the features at once.