centos7安装docker并设置开机启动

• 版本要求：查看内核版本，需大于3.10

[root@localhost ~]# uname -r
3.10.-327.10..el7.x86_64

• 更新内核：如果是生产机器务必慎重更新内核，避免出现不必要的问题。

sudo yum update

• 安装docker

[root@localhost ~]# curl -sSL https://get.docker.com/ | sh 
+ sh -c 'sleep 3; yum -y -q install docker-engine'
Delta RPMs disabled because /usr/bin/applydeltarpm not installed.
warning: /var/cache/yum/x86_64//docker-main-repo/packages/docker-engine-selinux-1.10.-.el7.centos.noarch.rpm: Header V4 RSA/SHA512 Signature, key ID 2c52609d: NOKEY
Public key for docker-engine-selinux-1.10.-.el7.centos.noarch.rpm is not installed
Importing GPG key 0x2C52609D:
 Userid     : "Docker Release Tool (releasedocker) <docker@docker.com>"
 Fingerprint:  8e89 f3a9  7c07 0adb f762  2c52 609d
 From       : https://yum.dockerproject.org/gpg
setsebool:  SELinux is disabled.

If you would like to use Docker as a non-root user, you should now consider
adding your user to the "docker" group with something like:

  sudo usermod -aG docker your-user

Remember that you will have to log out and back in for this to take effect!

• 启动docker

[root@localhost ~]# sudo service docker start
Redirecting to /bin/systemctl start  docker.service

• 测试

[root@localhost ~]# sudo docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
03f4658f8b78: Pull complete
a3ed95caeb02: Pull complete
Digest: sha256:8be990ef2aeb16dbcb9271ddfe2610fa6658d13f6dfb8bc72074cc1ca36966a7
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:
 . The Docker client contacted the Docker daemon.
 . The Docker daemon pulled the "hello-world" image from the Docker Hub.
 . The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 . 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 Hub account:
 https://hub.docker.com

For more examples and ideas, visit:
 https://docs.docker.com/userguide/

• 设置开机启动

[root@localhost ~]# systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.

• 将指定用户添加到用户组

usermod -aG docker your_username

　　退出，然后重新登录，以便让权限生效。