Install the docker tutorial under Centos
- 2020-05-15 02:40:00
- OfStack
Install via yum
Requires permission to root or to sudo
The yum package is updated to the latest
$ sudo yum update
Add the Docker yum source
$ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/$releasever/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF
Install Docker package
$ sudo yum install docker-engine
Start the Docker daemon
$ sudo service docker start
Verify that Docker is installed correctly by running a container with a test image
$ sudo docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from hello-world
a8219747be10: Pull complete
91c95931e552: Already exists
hello-world:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security.
Digest: sha256:aa03e5d0d5553b4c3473e89c8619cf79df368babd1.7.1cf5daeb82aab55838d
Status: Downloaded newer image for hello-world:latest
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.
(Assuming it was not already locally available.)
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
For more examples and ideas, visit:
http://docs.docker.com/userguide/
Script installation
You need permission to root or to sudo
The yum package is updated to the latest
$ sudo yum update
Run the Docker installation script
$ curl -sSL https://get.docker.com/ | sh
This script adds the docker.repo repository and installs Docker
Start the Docker daemon
$ sudo service docker start
Verify that Docker is installed correctly by running a container with a test image
$ sudo docker run hello-world
Create one Docker user group
The docker daemon is bound to Unix socket instead of TCP port. By default, Unix socket belongs to root users and users with sudo permissions. For this reason, the docker daemon needs 1 to run directly under the root user.
To avoid having to use sudo when you use the docker command, create a Unix group called docker and add users to it. When the docker daemon starts, it makes the ownership of the Unix socket read/writable by the docker group.
To avoid the need to use the sudo command when running the docker command, create an Unix user group called docker and add users who need to run docker. When you start running the docker daemon, members of the docker user group are given read and write access to Unix socket.
Create the docker user group and add users:
1. Required permissions of root or sudo
2. Create the docker user group and add users
sudo usermod -aG docker your_username
3. Log out and log in to your_username, or log out and log in again once under your_username, which ensures that your user is running the correct permissions.
4. Verify that the sudo command is no longer required to run docker
$ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/$releasever/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF
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Boot up and run docker
$ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/$releasever/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF
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