[root@localhost ~]# uname -r

3.10.-327.10..el7.x86_64

sudo yum update

[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!

[root@localhost ~]# sudo service docker start

Redirecting to /bin/systemctl start  docker.service

[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/

[root@localhost ~]# systemctl enable docker

Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.

usermod -aG docker your_username