Install Related Packages

$ sudo apt-get update # 先更新一下软件源库信息

$ sudo apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    software-properties-common

Add Software Repository

Official Repository

# Add Docker's official GPG key (to verify the legitimacy of downloaded packages, the GPG key of the software source needs to be added)
$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
# Set the apt repository address for the stable version
$ sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   $(lsb_release -cs) \
   stable"

Alibaba Cloud repository

$ curl -fsSL https://mirrors.aliyun.com/docker-ce/linux/ubuntu/gpg | sudo apt-key add -

$ sudo add-apt-repository \
     "deb [arch=amd64] https://mirrors.aliyun.com/docker-ce/linux/ubuntu \
     $(lsb_release -cs) \
     stable"

Install Docker

$ sudo apt-get update
$ sudo apt-get install docker-ce # Install the latest version of Docker

If you need to install a specific version, use the following commands:

$ apt-cache policy docker-ce # View all available Docker versions for installation
$ sudo apt-get install docker-ce=18.03.0~ce-0~ubuntu # Install a specific version of Docker

Check if Docker is installed successfully

$ docker --version # Check installed Docker version

## Adding Access Permissions

If you run Docker at this point as a non-root user, you will encounter an error:

```bash
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.26/images/json: dial unix /var/run/docker.sock: connect: permission denied

Let's check the permissions:

$ cd /var/run
$ ll | grep docker

Output is as follows

drwx------ 8 root root 180 Nov 21 16:36 docker -rw-r--r-- 1 root root 5 Nov 21 16:35 docker.pid srw-rw---- 1 root docker 0 Nov 21 16:35 docker.sock

As you can see, the owner of `docker.sock` is the `docker` group. Therefore, we need to add the current user to this group.

```bash
$ sudo gpasswd -a ${USER} docker

Restart Docker.

sudo service docker restart

Switch the current session to the new group or restart the X session.

newgrp - docker

Note: The last step is necessary. Otherwise, because the groups command retrieves cached group information, the newly added group information may not take effect, causing docker images to also throw an error.

Running Docker Tests

Now you can run the hello-world test～

$ docker run hello-world

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/get-started/

That's all there is to the installation～

References

https://docs.docker.com/get-started/#test-docker-version https://www.jianshu.com/p/a12558da034e https://www.jianshu.com/p/95e397570896