Docker Debugger

Docker Debugger

Instructions

When debugging Docker issues:

1. Identify the problem type: Build, runtime, networking, or performance
2. Gather information using diagnostic commands
3. Analyze logs and errors
4. Apply fixes

Diagnostic Commands

# Check running containers
docker ps -a

# View container logs
docker logs <container_id> --tail 100 -f

# Inspect container
docker inspect <container_id>

# Check resource usage
docker stats

# View container processes
docker top <container_id>

# Execute shell in running container
docker exec -it <container_id> /bin/sh

# Check Docker disk usage
docker system df

# View build history
docker history <image_name>

Common Issues & Solutions

1. Container exits immediately

# Check exit code
docker inspect <container_id> --format='{{.State.ExitCode}}'

# View last logs
docker logs <container_id>

Fixes:

• Ensure CMD/ENTRYPOINT runs a foreground process
• Check for missing dependencies
• Verify environment variables

2. Build fails