[docker]初歩的なミス・・

CentOS7にdockerをインストール(yum install docker)したのですが、
イメージもPullできず、バージョン確認さえ出来ませんでした。

うまく動かないdockerコマンド

[user@localhost docker]# docker ps -a
FATA[0000] Get http:///var/run/docker.sock/v1.18/containers/json?all=1: dial unix /var/run/docker.sock: no such file or directory. Are you trying to connect to a TLS-enabled daemon without TLS?
[user@localhost docker]# docker info
FATA[0000] Get http:///var/run/docker.sock/v1.18/info: dial unix /var/run/docker.sock: no such file or directory. Are you trying to connect to a TLS-enabled daemon without TLS?
[user@localhost docker]# docker --vsersion
Docker version 1.6.2, build ba1f6c3/1.6.2
[user@localhost docker]# docker pull centos:coentos7entos7
FATA[0000] Post http:///var/run/docker.sock/v1.18/images/create?fromImage=centos%3Acentos7: dial unix /var/run/docker.sock: no such file or directory. Are you trying to connect to a TLS-enabled daemon without TLS?
[user@localhost docker]# docker version
Client version: 1.6.2
Client API version: 1.18
Go version (client): go1.4.2
Git commit (client): ba1f6c3/1.6.2
OS/Arch (client): linux/amd64
FATA[0000] Get http:///var/run/docker.sock/v1.18/version: dial unix /var/run/docker.sock: no such file or directory. Are you trying to connect to a TLS-enabled daemon without TLS?
・・・・

何のことはない、dockerを動かしていなかった・・
対応は「systemctl」で動かすこと

[user@localhost docker]# systemctl start dcdocker
[user@localhost docker]# systemctl enable docker
ln -s '/usr/lib/systemd/system/docker.service' '/etc/systemd/system/multi-user.target.wants/docker.service'
[user@localhost docker]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
[user@localhost docker]# docker ps -aversion
Client version: 1.6.2
Client API version: 1.18
Go version (client): go1.4.2
Git commit (client): ba1f6c3/1.6.2
OS/Arch (client): linux/amd64
Server version: 1.6.2
Server API version: 1.18
Go version (server): go1.4.2
Git commit (server): ba1f6c3/1.6.2
OS/Arch (server): linux/amd64