pod health check

This test is to check the health of K8s PODs. Two types of health checks can be performed:

1. Liveness Test
2. Readiness Test

For (1), a liveness probe will check if the container which is configured in the POD is still running. If the liveness probe fails, the kubelet will kill the container and re-start the container

For (2), a readiness probe will determine if a container is ready to service requests. If the readiness probe fails, the endpoints controller will ensure that the container has its IP address removed from the endpoints of all services. A readiness probe can be used to signal to the endpoints controller that even though a container is running, it should not receive any traffic from a proxy.