PXEブートのやりかた
  * http://lab.astamuse.co.jp/entry/2018/10/24/160000
  * https://blog.dshimizu.jp/article/901
  * https://qiita.com/hino9966/items/7c7043094a0ad3928e78

ディスクレス
  * https://www.hiroom2.com/2017/07/02/ubuntu-1604-pxeboot-thin-client-nfs-ja/
  * https://adsaria.hatenadiary.org/entry/20090206/1233905956
  * https://sites.google.com/a/g.wakayama-u.jp/yasue/linux/networkboot-with-linuxmint17
  * https://blog.michinari-nukazawa.com/2015/09/pxe-boot-ubuntu-1404-on-pxe-pdhcp.html