What is the default container restart policy in Kubernetes?

The default container restart policy in Kubernetes is set to "Always." This means that if a container within a pod stops for any reason, Kubernetes will automatically attempt to restart it. This policy is particularly beneficial for applications that need to be highly available and should continue running without manual intervention.

The "Always" restart policy ensures that the system maintains the desired state of the application as defined in the pod specification. If the container exits successfully or fails, Kubernetes will still ensure that the container restarts. This default behavior is essential for many stateful applications and services that require continuous operation.

While other restart policies, such as “On failure” or “Never,” exist, they serve specific use cases. For instance, the “On failure” policy restarts the container only if it crashes, not when it exits cleanly, and “Never” indicates that the container should not be restarted under any circumstances. The "Sometimes" option does not correspond to a valid Kubernetes restart policy.

Understanding this default behavior can help administrators design and manage their applications in a way that adheres to their uptime and reliability expectations.