Use sysctl to change kernel params in docker file,will the running container affect Host kernel

Question

Docker share the kernal with Host.

If I add this in docker file and build a image:

RUN sysctl -w fs.nr_open=2000000
RUN sysctl -w net.ipv4.tcp_tw_recycle=1

Then I run the docker container by this image, will this config affect host OS?

I don't want to affect the host or other containers which doesn't change this configuration.

Answer 1

No, that will not affect the host.

There are some special permissions you can give to your container while running it to be able to affect your host (partially), e.g. privilege, or some other additional specific purpose permissions.

Check this link for more information:

https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities

In your case, I don't know about the first line, but about the second line, as long as you are not using host networking (but any other mode like the default bridge), your host is safe.