[docker: Error response from daemon: unable to find "systemd" in controller set: unknown]

Hi,

 

In my funtoo hosting container, I tried out docker following this page

https://www.funtoo.org/Package:Docker 

 

After emerge I got this message output

* Unable to find kernel sources at /usr/src/linux
 * Unable to calculate Linux Kernel version for build, attempting to use running version
 *   CONFIG_MEMCG_SWAP_ENABLED:  is not set when it should be.
 *   CONFIG_CGROUP_HUGETLB:      is not set when it should be.
 *   CONFIG_RT_GROUP_SCHED:      is not set when it should be.
 * Please check to make sure these options are set correctly.
 * Failure to do so may cause unexpected problems.

Should I worried about this?

The symbolink /usr/src/linux is pointing to linux-debian-sources-lts-4.9.130, but the host seems to running 4.9.110

I removed the old symbolink, copied linux-debian-sources-lts-4.9.110 from host folder to there and made a new symbolink

 

When I tried to run the hello world docker image

docker run --detach --name app carinamarina/hello-world-app

I got this problem:

 

docker: Error response from daemon: unable to find "systemd" in controller set: unknown. 

 

I know funtoo by default is not using systemd. 

What settings/change should I make to the system to use docker for my development?

 

Thank you.