https://www.sumologic.com/blog/code/lxc-lxd-explaining-linux-containers/
see also:
https://linuxcontainers.org/lxc/introduction/
http://blog.csdn.net/preterhuman_peak/article/details/40857117
http://blog.csdn.net/tongtest/article/details/53440437
https://www.toptal.com/linux/separation-anxiety-isolating-your-system-with-linux-namespaces
http://www.cnblogs.com/BeautyConcurrency/p/4083628.html
http://blog.chinaunix.net/uid-20788636-id-4479145.html
http://jingyan.baidu.com/article/ff42efa92ce3cfc19f220257.html
https://stackoverflow.com/questions/16047306/how-is-docker-different-from-a-normal-virtual-machine
https://baike.baidu.com/item/ring0/5373289?fr=aladdin