[nsenter安装使用]
cd /tmp curl https://www.kernel.org/pub/linux/utils/util-linux/v2.24/util-linux-2.24.tar.gz tar -zxvf util-linux-2.24.tar.gz cd util-linux-2.24 ./configure --without-ncurses make nsenter cp nsenter /usr/local/bin
参考资料：
http://www.oschina.net/translate/enter-docker-container?cmp
https://jpetazzo.github.io/2014/06/23/docker-ssh-considered-evil/
http://www.cnblogs.com/ggjucheng/archive/2013/01/13/2856901.html