Summary of essential Docker commands for developers

This article mainly explains the installation of the Docker environment and the use of common Docker commands. Mastering these is very helpful for the deployment of applications in the Docker environment.

Introduction to Docker

Docker is an open source application container engine that allows developers to package their applications and dependencies into a portable image and then publish it to any popular Linux or Windows machine. Using Docker makes it easier to package, test, and deploy applications.

Docker environment installation

1. Install yum-utils:

yum install -y yum-utils device-mapper-persistent-data lvm2

2. Add the docker repository location to the yum source:

yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

3. Install docker:

yum install docker-ce

4. Start Docker:

systemctl start docker

Docker image common commands

Search Mirror

docker search java

Download image

docker pull java:8

How to find the versions supported by the image

Since the docker search command can only find out whether the image exists, but cannot find the version supported by the image, we need to search for supported versions through docker hub.

Enter the official website of docker hub, address: https://hub.docker.com

Then search for the required image:

Check the versions supported by the image:

Download the image:

docker pull nginx:1.17.0

List images

docker images 

Deleting an image

Delete an image by specifying its name

docker rmi java:8

Delete an image by specifying its name (mandatory)

docker rmi -f java:8

Force delete all images

docker rmi -f $(docker images)

Docker container common commands

Create and start a container

docker run -p 80:80 --name nginx -d nginx:1.17.0

-d option: indicates background operation

--name option: specifies the name of the container after running as nginx, and then you can operate the container by name

-p option: specifies port mapping, the format is: hostPort:containerPort

List Containers

List running containers:

docker ps

List all containers

docker ps -a

Stop the container

# $ContainerName and $ContainerId can be queried using the docker ps command	
docker stop $ContainerName(or $ContainerId)

for example:

docker stop nginx	
#or	
docker stop c5f5d5125587

Force stop container

docker kill $ContainerName(or $ContainerId)

Start a stopped container

docker start $ContainerName(or $ContainerId)

Entering the container

First query the pid of the container:

docker inspect --format "{{.State.Pid}}" $ContainerName(or $ContainerId)

Enter the container according to the container's pid:

nsenter --target "$pid" --mount --uts --ipc --net --pid 

Deleting a container

Delete the specified container:

docker rm $ContainerName(or $ContainerId)

Force delete all containers;

docker rm -f $(docker ps -a -q)

View the container logs

docker logs $ContainerName(or $ContainerId) 

View the IP address of the container

docker logs $ContainerName(or $ContainerId) 

Synchronize host time to container

docker cp /etc/localtime $ContainerName(or $ContainerId):/etc/

Check Docker's CPU, memory, network, and IO usage on the host machine

View the status of a specified container:

docker stats $ContainerName(or $ContainerId) 

View all containers:

docker stats -a

Enter bash inside the Docker container

docker exec -it $ContainerName /bin/bash

Modify the storage location of the Docker image

View the storage location of the Docker image:

docker info | grep "Docker Root Dir"

Shut down the Docker service:

systemctl stop docker

Move the directory to the target path:

mv /var/lib/docker /mydata/docker

Create a soft link:

ln -s /mydata/docker /var/lib/docker 

This concludes this article on the essential Docker commands for developers. For more Docker command content, please search 123WORDPRESS.COM’s previous articles or continue to browse the following related articles. I hope everyone will support 123WORDPRESS.COM in the future!