Useful Docker Commands

docker-commands.md

Building Images

By default, Docker looks for a file named Dockerfile when building images.

• docker build -t express-prod-i .
  • -t - Optionally tag, or name a docker image to avoid referring to the auto-generated ID (e.g. 50e8dde7e180)
  • . - Look for the Dockerfile in the current directory
  • -f - Override default Dockerfile name

Dockerfile

• RUN - Is an image build step
• CMD - Is a command the contanier executes when you launch the built image

List Images

• docker images

Review Image Layers

• docker history express-prod-i

Running Image Instances

• docker run -d --name express-prod-app -p 7000:3000 -v $(pwd):/var/app express-prod-i
  • -d - Detached mode. Don't tie up current terminal.
  • --name - Name the container
  • -p - Map local host port 7000 to the exposed container port 3000
  • express-prod-i - The image we want to generate and run
  • -v - Mount a volume on the host machine.
    • $(pwd):/var/app mounts the present working directory on the host machine to /var/app on the container

Verify Running Containers

• docker ps - Show running containers
• docker ps -a - Show ALL containers. Useful when something goes wrong and the container stops.

Check Container Logs

• docker logs hackershall-prod-app - Check the hackersall-prod-app container logs

Execute a Shell

• docker exec -it hackershall-prod-app /bin/sh
  • Access a bash shell on a running container
  • -it - interactive terminal

Inspecting Containers

• docker inspect express-prod-app
  • Shows volume and mount information within "Mounts"

Stopping and Starting Containers

• docker stop express-prod-app
• docker start express-prod-app

Deleting Containers

• docker rm express-prod-app - Delete the express-prod-app container
• docker rm $(docker ps -a -q) - Delete ALL containers

Deleting Images

• docker rmi express-prod-i - Delete the express-prod-i image
• docker rmi $(docker images -q) - Delete ALL images

Excluding Files in an Image

• You can specify patterns to ignore when building an image within a .dockerignore file

Cleanup

• docker system prune
  • Remove stopped containers
  • Remove images without any containers
  • Remove orphaned volumes

Docker Compose

• docker-compose build - Build or rebuild services
• docker-compose up - Create and start containers
• docker-compose start - Start services
• docker-compose stop - Stop services
• docker-compose down - Stop and remove containers, networks, images, and volumes