Main Reference from official docker website: installation on Centos
Docker requires a 64-bit installation regardless of your CentOS version. Also, your kernel must be 3.10 at least, which CentOS 7 runs.
To check your current kernel version, open a terminal and use
uname -r to display your kernel version:
$ uname -r 3.10.0-229.el7.x86_64
Finally, it is recommended that you fully update your system. Please keep in mind that your system should be fully patched to fix any potential kernel bugs. Any reported kernel bugs may have already been fixed on the latest kernel packages.
Install with yum
- Log into your machine as a user with
- Make sure your existing yum packages are up-to-date.
$ sudo yum update
- Add the yum repo.
$ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF' [dockerrepo] name=Docker Repository baseurl=https://yum.dockerproject.org/repo/main/centos/7/ enabled=1 gpgcheck=1 gpgkey=https://yum.dockerproject.org/gpg EOF
- Install the Docker package.
$ sudo yum install docker-engine
- Start the Docker daemon.
$ sudo service docker start
dockeris installed correctly by running a test image in a container.
$ 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/
Create a docker group
docker daemon binds to a Unix socket instead of a TCP port. By default that Unix socket is owned by the user
root and other users can reach it with
sudo. For this reason,
docker daemon always runs as the
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
dockergroup is equivalent to the
rootuser; For details on how this impacts security in your system, see Docker Daemon Attack Surface for details.
To create the
docker group and add your user:
- Log into Centos as a user with
- Create the
sudo groupadd docker
- Add your user to
sudo usermod -aG docker your_username
- Log out and log back in.This ensures your user is running with the correct permissions.
- Verify your work by running
$ docker run hello-world
Start the docker daemon at boot
To ensure Docker starts when you boot your system, do the following:
$ sudo chkconfig docker on
If you need to add an HTTP Proxy, set a different directory or partition for the Docker runtime files, or make other customizations, read our Systemd article to learn how to customize your Systemd Docker daemon options.