Docker Logs & Debugging

Monitoring and debugging are essential when working with Docker containers. Docker provides built-in commands to view logs, inspect containers, and troubleshoot issues efficiently.

View Container Logs

# View logs of a container
docker logs my-container

# Follow logs in real-time
docker logs -f my-container

# Show last 50 lines
docker logs --tail 50 my-container

# Show logs with timestamps
docker logs -t my-container

Check Running Containers

docker ps

To see all containers (including stopped):

docker ps -a

Inspect Container Details

docker inspect my-container

This shows detailed information like IP address, mounts, environment variables, and configuration.

Execute Commands Inside Container

# Open bash shell
docker exec -it my-container bash

# Run a single command
docker exec my-container ls

Check Resource Usage

docker stats

This shows CPU, memory, and network usage for running containers.

View Container Processes

docker top my-container

Debugging Common Issues

• Container not starting: Check logs using docker logs
• Port not accessible: Verify port mapping with -p
• App crash: Check environment variables and dependencies
• Permission issues: Verify file permissions inside container

Restart & Remove Containers

# Restart container
docker restart my-container

# Stop container
docker stop my-container

# Remove container
docker rm my-container

Debug with Docker Compose

# View logs of all services
docker compose logs

# Follow logs
docker compose logs -f

# Logs of specific service
docker compose logs app

Summary

• Use docker logs to monitor container output.
• Use docker exec to debug inside containers.
• Use docker inspect for detailed configuration.
• Use docker stats to monitor performance.