CentOS7 启动docker.service失败

Hi all:
在CentOS7上执行yum install docker安装docker后，对docker进行测试出现如下错误：

[root@localhost /]# docker run -i -t ubuntu /bin/bash
2014/11/27 15:21:52 Post http:///var/run/docker.sock/v1.14/containers/create: read unix /var/run/docker.sock: connection reset by peer

搜索后得知是没有启动docker服务，执行启动服务失败：

[root@localhost /]# systemctl start docker.service
Job for docker.service failed. See 'systemctl status docker.service' and 'journalctl -xn' for details.
[root@localhost /]# systemctl status docker.service
docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled)
   Active: failed (Result: start-limit) since Thu 2014-11-27 15:03:24 CST; 13s ago
     Docs: http://docs.docker.io
  Process: 4559 ExecStart=/usr/bin/docker -d $OPTIONS $DOCKER_STORAGE_OPTIONS (code=exited, status=1/FAILURE)
 Main PID: 4559 (code=exited, status=1/FAILURE)

Nov 27 15:03:24 localhost.localdomain systemd[1]: docker.service: main proces...
Nov 27 15:03:24 localhost.localdomain systemd[1]: Failed to start Docker Appl...
Nov 27 15:03:24 localhost.localdomain systemd[1]: Unit docker.service entered...
Nov 27 15:03:24 localhost.localdomain systemd[1]: docker.service holdoff time...
Nov 27 15:03:24 localhost.localdomain systemd[1]: Stopping Docker Application...
Nov 27 15:03:24 localhost.localdomain systemd[1]: Starting Docker Application...
Nov 27 15:03:24 localhost.localdomain systemd[1]: docker.service start reques...
Nov 27 15:03:24 localhost.localdomain systemd[1]: Failed to start Docker Appl...
Nov 27 15:03:24 localhost.localdomain systemd[1]: Unit docker.service entered...
Hint: Some lines were ellipsized, use -l to show in full.

请问是什么问题？？？