Running Stateful Apps

Stateful apps like databases or queues need stable network identity and durable storage.

Core requirements

• Stable identity: predictable Pod names
• Durable storage: data survives Pod recreation
• Ordered startup/shutdown: avoid all replicas restarting together

Common stack

• StatefulSet + PVC
• Headless Service for stable DNS
• Backup and restore workflows

Practice tips

• Start with a single instance, then scale out
• Use readinessProbe to avoid routing traffic too early

Practical notes

• Start with a quick inventory: kubectl get nodes, kubectl get pods -A, and kubectl get events -A.
• Compare desired vs. observed state; kubectl describe usually explains drift or failed controllers.
• Keep names, labels, and selectors consistent so Services and controllers can find Pods.

Quick checklist

• The resource matches the intent you described in YAML.
• Namespaces, RBAC, and images are correct for the target environment.
• Health checks and logs are in place before promotion.

References

• Stateful Applications Tutorial
• StatefulSets