我按照docker的指示进行安装和验证docker的安装（来自http://docs.docker.com/linux/step_one/）。

我在2台Ubuntu 14.04机器上尝试过，在启动docker daemon时都遇到以下错误：

$ sudo docker daemon
INFO[0000] Listening for HTTP on unix (/var/run/docker.sock) 
INFO[0000] [graphdriver] using prior storage driver "aufs" 
INFO[0000] Option DefaultDriver: bridge                 
INFO[0000] Option DefaultNetwork: bridge                
WARN[0000] Running modprobe bridge nf_nat br_netfilter failed with    message: modprobe: WARNING: Module br_netfilter not found. , error: exit status 1 
INFO[0000] Firewalld running: false                     
WARN[0000] Your kernel does not support cgroup memory limit: mountpoint for memory not found 
WARN[0000] mountpoint for cpu not found                 
FATA[0000] Error starting daemon: Devices cgroup isn't mounted

感谢您为解决此问题提供的帮助。