docker on centos

install docker-engine

install with yum

login with sudo or root privileges
make sure your existing 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
```

enable the service

 $ sudo systemctl enable docker.service

start the docker daemon
```
 $ sudo systemctl start docker
```
verify
```
 $ sudo docker run --rm hello-world
```

install with the script

login with sudo or root privileges
make sure your existing packages are up-to-date
```
 $ sudo yum update
```

run the docker installation script

 $ curl -fsSL https://get.docker.com/ | sh
 + sudo -E sh -c 'sleep 3; yum -y -q install docker-engine'
 warning: rpmts_HdrFromFdno: Header V4 RSA/SHA1 Signature, key ID 2c52609d: NOKEY
 Importing GPG key 0x2C52609D:
  Userid: "Docker Release Tool (releasedocker) <docker@docker.com>"
  From  : https://yum.dockerproject.org/gpg

 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 dc

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

enable the service

 $ sudo systemctl enable docker.service

start the docker daemon
```
 $ sudo systemctl start docker
```
verify
```
 $ sudo docker run --rm hello-world
```

install docker-io (old version)

install the epel repo

 $ rpm -iUvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

update our packages:
```
 $ yum update -y
```
docker-io package:
```
 $ yum -y install docker-io
```
start the docker daemon
```
 $ service docker start
```
config start with the server boots
```
 $ chkconfig docker on
```

fixed

error

message

 Error: Package: docker-engine-1.12.5-1.el7.centos.x86_64 (dockerrepo)
            Requires: device-mapper-libs >= 1.02.90-1
            Installed: device-mapper-libs-1.02.79-8.el6.x86_64 (@anaconda-CentOS-201311291202.x86_64/6.5)
                device-mapper-libs = 1.02.79-8.el6
 Error: Package: docker-engine-1.12.5-1.el7.centos.x86_64 (dockerrepo)
            Requires: libsystemd.so.0(LIBSYSTEMD_209)(64bit)
 Error: Package: docker-engine-1.12.5-1.el7.centos.x86_64 (dockerrepo)
            Requires: libseccomp.so.2()(64bit)
 Error: Package: docker-engine-1.12.5-1.el7.centos.x86_64 (dockerrepo)
            Requires: libsystemd.so.0()(64bit)
 Error: Package: docker-engine-1.12.5-1.el7.centos.x86_64 (dockerrepo)
            Requires: libc.so.6(GLIBC_2.17)(64bit)
 Error: Package: docker-engine-1.12.5-1.el7.centos.x86_64 (dockerrepo)
            Requires: selinux-policy >= 3.13.1-23
            Installed: selinux-policy-3.7.19-231.el6.noarch (@anaconda-CentOS-201311291202.x86_64/6.5)
                selinux-policy = 3.7.19-231.el6
 Error: Package: docker-engine-1.12.5-1.el7.centos.x86_64 (dockerrepo)
            Requires: libdevmapper.so.1.02(DM_1_02_97)(64bit)
 Error: Package: docker-engine-1.12.5-1.el7.centos.x86_64 (dockerrepo)
            Requires: systemd-units
 Error: Package: docker-engine-selinux-1.12.5-1.el7.centos.noarch (dockerrepo)
            Requires: selinux-policy-base >= 3.13.1-23
            Installed: selinux-policy-targeted-3.7.19-231.el6.noarch (@anaconda-CentOS-201311291202.x86_64/6.5)
                selinux-policy-base = 3.7.19-231.el6
            Available: selinux-policy-minimum-3.7.19-231.el6.noarch (os)
                selinux-policy-base = 3.7.19-231.el6
            Available: selinux-policy-mls-3.7.19-231.el6.noarch (os)
                selinux-policy-base = 3.7.19-231.el6
 Error: Package: docker-engine-selinux-1.12.5-1.el7.centos.noarch (dockerrepo)
            Requires: selinux-policy-targeted >= 3.13.1-23
            Installed: selinux-policy-targeted-3.7.19-231.el6.noarch (@anaconda-CentOS-201311291202.x86_64/6.5)
                selinux-policy-targeted = 3.7.19-231.el6
  You could try using --skip-broken to work around the problem
  You could try running: rpm -Va --nofiles --nodigest

use –skip-broken

 $ yum install docker-engine --skip-broken
 ...
 Packages skipped because of dependency problems:
     audit-libs-python-2.2-2.el6.x86_64 from os
     docker-engine-1.12.5-1.el7.centos.x86_64 from dockerrepo
     docker-engine-selinux-1.12.5-1.el7.centos.noarch from dockerrepo
     libselinux-python-2.0.94-5.3.el6_4.1.x86_64 from os
     libsemanage-python-2.0.43-4.2.el6.x86_64 from os
     libtool-ltdl-2.2.6-15.5.el6.x86_64 from os
     policycoreutils-python-2.0.83-19.39.el6.x86_64 from os
     setools-libs-3.3.7-4.el6.x86_64 from os
     setools-libs-python-3.3.7-4.el6.x86_64 from os

final fixed
1. docs for installation on linux centos’s prerequisites Docker requires a 64-bit OS and version 3.10 or higher of the Linux kernel
2. check my post 2016-12-23-upgrade-centos-6.5-kernel-from-2.6-to-3.10
```
 # you should upgrade os kernel first
```