What is Kubernetes Pod Lifecycle Init Container RestartPolicy?

Question

Accepted Answer

**Init Container Restart** — control init container restart behavior.

```yaml
apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  initContainers:
  - name: init-1
    image: busybox:1.36
    command: ["sh", "-c", "echo init-1 && exit 0"]
    restartPolicy: Never  # Don't restart on success
  - name: init-2
    image: busybox:1.36
    command: ["sh", "-c", "echo init-2 && exit 1"]  # Will fail
    restartPolicy: Always  # Restart on failure
  - name: init-3
    image: busybox:1.36
    command: ["sh", "-c", "echo init-3 && exit 0"]
    # Default: Always
  containers:
  - name: app
    image: myapp:latest
    restartPolicy: Always
```

```bash
# Check init container status
kubectl get pod my-pod -o jsonpath='{.status.initContainerStatuses}' | jq

# Check restart count
kubectl get pod my-pod -o jsonpath='{.status.initContainerStatuses[*].restartCount}'

# Watch init containers
kubectl get pod my-pod -w
kubectl describe pod my-pod | grep -A 10 "Init Containers"

# Check last state
kubectl get pod my-pod -o jsonpath='{.status.initContainerStatuses[*].lastState}' | jq

# View init container logs
kubectl logs my-pod -c init-1
kubectl logs my-pod -c init-2 --previous  # Previous instance
```

**Restart Policies:**
- Always: always restart.
- OnFailure: restart only on non-zero exit.
- Never: don't restart.

**Behavior:**
- Init containers run sequentially.
- Each must complete before next starts.
- Main containers start only after all init complete.
- RestartPolicy: Always (default) for init containers.

DevOps: What is Kubernetes Pod Lifecycle Init Container RestartPolicy?