30 Essential Docker Commands: A Practical Guide for SREs
Updated
•4 min read
1. Container Management (Lifecycle)
| Command | Purpose | Example |
docker ps | List running containers. | docker ps -a (to see all containers, including those that exited with errors). |
docker run | Create and start a container. | docker run -d --name web nginx (run a web server in the background/detached). |
docker stop | Stop a running container. | docker stop $(docker ps -q) (stop all running containers at once). |
docker rm | Remove a container. | docker rm -f web (force removal of a running container). |
docker exec | Run a command in a container. | docker exec -it web bash (get an interactive shell inside a container). |
docker logs | Fetch container logs. | docker logs -f --tail 100 web (follow the last 100 log lines in real-time). |
2. Image Management
| Command | Purpose | Example |
docker images | List available images. | docker images -q (get only the IDs of all local images). |
docker pull | Download an image. | docker pull redis:latest (ensure you have the latest version before deployment). |
docker build | Build an image from a Dockerfile. | docker build -t my-app:v1 . (tag a new version of your application). |
docker rmi | Remove an image. | docker rmi $(docker images -f "dangling=true" -q) (clean up unused/dangling images). |
docker tag | Create a tag for an image. | docker tag my-app:v1 myrepo/my-app:v1 (prepare an image for a registry). |
docker push | Upload an image to a registry. | docker push myrepo/my-app:v1 (deploy the image to Docker Hub or ACR/ECR). |
3. Observability & Troubleshooting
| Command | Purpose | Example |
docker stats | Live resource usage. | docker stats --no-stream (get a snapshot of CPU/RAM usage per container). |
docker inspect | Low-level info on objects. | docker inspect web (Information about the container) |
docker top | Display running processes. | docker top web (see what processes are running inside the container host-side). |
docker port | List port mappings. | docker port web (verify which host port is mapped to the container's port). |
docker events | Real-time events from server. | docker events --since 1h (audit what happened in the Docker engine recently). |
docker diff | Changes in the FS. | docker diff web (see what files were modified/added in the container layer). |
4. Network & Volumes
| Command | Purpose | Example |
docker network ls | List networks. | docker network ls (check available drivers like bridge, host, or overlay). |
docker network inspect | Detailed network info. | docker network inspect bridge (see which containers are attached to a network). |
docker volume ls | List volumes. | docker volume ls (identify persistent data volumes). |
docker volume prune | Remove unused volumes. | docker volume prune (recover disk space from orphaned volumes). |
docker cp | Copy files to/from container. | docker cp web:/etc/nginx/nginx.conf . (extract a config file for local review). |
docker network connect | Connect container to network. | docker network connect my-net web (dynamically attach a container to a new network). |
5. Advanced & Cleanup
| Command | Purpose | Example |
docker system prune | Total cleanup. | docker system prune -a --volumes (wipe everything unused to free up disk). |
docker system df | Show docker disk usage. | docker system df (diagnose why the Docker partition is full). |
docker-compose up | Orchestrate multiple containers. | docker-compose up -d (deploy an entire stack defined in a YAML). |
docker-compose logs | View logs from a stack. | docker-compose logs -f app (follow logs for a specific service in the stack). |
docker commit | Create image from container. | docker commit web my-emergency-image (save a container's state for forensics). |
docker wait | Wait for a container to stop. | docker wait web (useful in scripts to take action after a container finishes). |
