My docker image is tianon/gentoo-stage3:latest
And my host system is centos7 and my docker version is Docker version 1.6.0, build 4749651
When I run this image , I found I can not use rc-update command. ls -l /sbin/rc* show empty result.
I have no idea what package I need to install.
rc-update is provided by the sys-apps/openrc package. Why you don't have it is a mystery without knowing more about the image / setup. The image may be using systemd, but that doesn't necessarily rule out the openrc package being installed.
You should run: ps -p 1 -o command. That will give you an indication of your init system. If it says systemd, whatever you are trying to do with rc-update should probably be done with the systemctl command instead.
If you are indeed using sysvinit / openrc, I suggest you update your openrc package by emerge -a openrc That will restore the rc-update command.
