RedHat 啟動 docker報錯：
錯誤：Error starting daemon: SELinux is not supported with the overlay2 graph driver on t...=false)
解決方法：
https://stackoverflow.com/questions/45461307/selinux-is-not-supported-with-the-overlay-graph-driver
RedHat7安裝docker的方法：
https://stackoverflow.com/questions/45461307/selinux-is-not-supported-with-the-overlay-graph-driver