Docker Commands

If you are new to Docker, here’s my notes on getting started with the tool.


I completed the course on “Docker Quickstart” at LinuxAcademy today. Over the course of I made notes on the important commands. Here’s my notes.

Installing docker

All commands as root on CentOs7

cd /etc/yum.repos.d
vim docker.repo
name=Docker Repository

yum install docker-engin

systemctl enable docker
systemctl start docker

usermod -a -G docker <username>
cat /etc/group | grep docker #should use the <username> as the group for the docker program

Docker commands

List images

docker images

List running docker processes

docker ps

List all processes that were ever run
docker ps -a

List only the container ids

docker ps -a -q

Running processes

docker run <image>
docker run -d <image> = run in disconnected / daemon mode
docker run --name="Some Name" = name the running instance
docker start <name> = will restart a closed / exited instance of the image
docker exec -it <name> <command> = run a command within a running container without changing the state of the running container
docker stop <name> = stop a running container by using the name

Cleaning up docker

docker rm containerid = removes an instance of the container that was run
docker rm `docker ps -a -q` = remove all stopped containers
docker rmi image-name = removes the docker image and its dependencies

Redirect port

docker run -P = will redirect the container's port to a random port on the host machine's user port (port no 32,000+)
docker run -p 8080:80 = will redirect the container's port 80 to a port 8080 on the host machine's user port 
docker port <container-name> = will list the port mapping information

Adding volume

using the "-v" option mounts the local file system. eg to mount for an nginx on centos
-v /home/user/www:/usr/share/nginx/html

Building a Docker file

docker login --username=<username>
Enter password

docker push username/repo

Author: akshayrangananth

CDN Specialist, Web performance evangelist, and SEO tinkerer.

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