Docker

What is Docker?

Docker provides the ability to package and run an application in a loosely isolated environment called a container. The isolation and security allows you to run many containers simultaneously on a given host. Containers are lightweight and contain everything needed to run the application, so you do not need to rely on what is currently installed on the host. You can easily share containers while you work, and be sure that everyone you share with gets the same container that works in the same way.

Download CLI Cheat Sheet that we will go through next.

DOCKER INSTALLATION

Docker Desktop is available for Mac, Linux and Windows

• https://docs.docker.com/desktop
• https://docs.docker.com/get-started/introduction/get-docker-desktop/

View example projects that use Docker

• https://github.com/docker/awesome-compose

Check out our docs for information on using Docker

• https://docs.docker.com

Alternatively, On Linux Install Docker Engine

• https://docs.docker.com/engine/install/

DOCKER IMAGES

Docker images are a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings.

 # Build an Image from a Dockerfile without the cache
docker build -t <image_name> . –no-cache

 # List local images
docker images

 # Delete an Image
docker rmi <image_name>

 # Remove all unused images
docker image prune

DOCKER HUB

Docker Hub is a service provided by Docker for finding and sharing container images with your team. Learn more and find images at https://hub.docker.com

 # Login into Docker
docker login -u <username>

 # Publish an image to Docker Hub
docker push <username>/<image_name>

 # Search Hub for an image
docker search <image_name>

 # Pull an image from a Docker Hub
docker pull <image_name>

DOCKER GENERAL COMMANDS

 # Start the docker daemon
docker -d
 # Get help with Docker. Can also use –help on all subcommands
docker --help
 # Display system-wide information
docker info

DOCKER CONTAINERS

A container is a runtime instance of a docker image. A container will always run the same, regardless of the infrastructure. Containers isolate software from its environment and ensure that it works uniformly despite differences for instance between development and staging

 # Create and run a container from an image, with a custom name:
docker run --name <container_name> <image_name>

 # Run a container with and publish a container’s port(s) to the host.
docker run -p <host_port>:<container_port> <image_name>

 # Run a container in the background
docker run -d <image_name>

 # Start or stop an existing container:
docker start|stop <container_name> (or <container-id>)

 # Remove a stopped container:
docker rm <container_name>

 # Open a shell inside a running container:
docker exec -it <container_name> sh

 # Fetch and follow the logs of a container:
docker logs -f <container_name>

 # To inspect a running container:
docker inspect <container_name> (or <container_id>)

 # To list currently running containers:
docker ps

 # List all docker containers (running and stopped):
docker ps --all

 # View resource usage stats
docker container stats

Try Some Docker Commands

• Open your CLI terminal and start a container by running the command:

docker run hello-world

• You should receive a Hello from Docker! in the output.

• Run welcome-to-docker as daemon mapping port 80 to 8080.

docker run -d -p 8080:80 docker/welcome-to-docker

• Visit http://localhost:8080 in your browser to access this container.
• Identify and Stop the running welcome-to-docker container.

 # view available docker images
docker image ls

 # view running docker container processes
docker ps

 # stop a running container by its CONTAINER ID or NAMES
docker stop <CONTAINER ID>