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:::tip Full debug guide See the complete WordPress/MySQL Debug Guide for an in-depth step-by-step walkthrough. :::

Kubernetes Troubleshooting Guide: WordPress & MySQL Connectivity

wordpress expects mysql on port 3306. name of db_host === service.name

Common Issues & Solutions​

Issue: "Error establishing database connection"​

Checklist:

  • MySQL service name matches WORDPRESS_DB_HOST
  • Both services in same namespace (or use FQDN)
  • MySQL port is 3306, not 80 or another port
  • Container exposes port 3306
  • Credentials match between WordPress and MySQL
  • MySQL pod is running and healthy
  • WordPress pod restarted after Secret changes

Issue: Wrong port configuration​

Correct configuration:

# In deployment
ports:
  - containerPort: 3306

# In service
ports:
  - port: 3306        # Port service listens on
    targetPort: 3306  # Port container listens on

Issue: Service endpoint is <none>​

Cause: Service selector doesn't match any pods

kubectl get pods -n wordpress --show-labels
kubectl describe svc mysql -n wordpress | grep Selector

Issue: Wrong namespace​

Solution: Both service and pods must be in same namespace, OR use FQDN: mysql.wordpress.svc.cluster.local

Quick Debug Commands​

# Check pods
kubectl get pods -n wordpress

# Check services
kubectl get svc -n wordpress

# Check endpoints
kubectl get endpoints -n wordpress

# Check env vars
kubectl exec -n wordpress deployment/wordpress -- printenv | grep WORDPRESS_DB

# Test DNS
kubectl exec -n wordpress deployment/wordpress -- nslookup mysql

# Force restart
kubectl rollout restart deployment/wordpress -n wordpress