What are the three main types of container health probes in Kubernetes?

The three main types of container health probes in Kubernetes are liveness, startup, and readiness.

Liveness probes are crucial for determining if a container is still running. If the liveness probe fails, the kubelet will kill the container, and the container will be subjected to the defined restart policy. This is essential in preventing a container from running in an unhealthy state indefinitely.

Startup probes are a newer feature that helps manage the startup process of containers. They are useful for applications that require a longer startup period. If the startup probe fails, Kubernetes will consider that the container has failed to start, allowing it to handle restarts effectively without interference from liveness or readiness checks during this phase.

Readiness probes indicate whether a container is ready to accept traffic from the service. Until a readiness probe passes, the container will not receive any traffic from the Kubernetes service. This is vital for ensuring that your application is fully operational and capable of handling requests before it starts taking traffic.

Each type of probe serves a distinct purpose in managing the lifecycle and health of containers within a Kubernetes cluster, making it important to understand and implement them appropriately for robust application deployment.