MySQL Replication

MySQL replication writes to a primary and replays changes on replicas so reads can be offloaded.

Key ideas

• Primary writes and generates binlog
• Replicas pull and replay the binlog
• Stable network identity matters

In Kubernetes

• StatefulSet keeps instance order
• Headless Service provides stable DNS
• Separate read/write Services if needed

Risks

• Replication lag can break consistency
• Primary failure needs a failover plan

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

• MySQL Replication
• StatefulSets
• Headless Services