Troubleshooting Dockerized Microservices

Common Microservices Issues

• Container not starting (missing environment/configs)
• Service unreachable (network misconfiguration)
• High latency or timeouts between services
• Database connection failures
• Log noise or missing logs

Useful Docker Debugging Commands

docker ps               # List running containers
docker logs myservice   # View logs
docker exec -it myservice /bin/sh   # Enter running container
docker inspect myservice            # See container config/details
docker network ls / inspect         # Check network health

Fixing Service Communication Issues

Checklist for when services can’t connect:

• Ensure both services are on the same Docker network
• Ping using container names (not localhost)
• Verify exposed ports and EXPOSE in Dockerfile
• Test with curl or Postman inside container

docker exec -it user-service curl http://order-service:5001/health

Performance Optimization Tips

• Use lighter base images (e.g., alpine)
• Enable caching for builds and dependencies
• Use multi-stage builds to reduce image size
• Profile resource usage with docker stats
• Ensure services aren’t blocking I/O or holding long DB connections

Real-World Fixes

Issue: Microservice hangs on startup

Fix: Check for DB availability or missing env variables.

Issue: Service crashes after deployment

Fix: Review logs with docker logs and verify config secrets.

Issue: Containers restart repeatedly

Fix: Set proper restart_policy and validate runtime scripts.

Troubleshooting microservices requires a systematic approach — leveraging logs, container tools, and network checks. By identifying patterns, you can eliminate bottlenecks and ensure reliable deployments.