/etc/hosts file of a docker container gets overwritten

Question

I create a docker container from a centOS 6.5 image. I make some changes to the /etc/hosts file. I then commit the container, and start the new image in a new container, and the /etc/hosts file gets overwritten. Is there a way of keeping the /etc/hosts file as it is?

Answer 1

No. See discussion here.

Docker does different things with /etc/hosts depending on what option you give to --net. In the default (bridged) mode, it writes an entry for the hostname and IP address of the container itself. There is no option where it leaves /etc/hosts as in the source image.

Your options include:

• have your container modify /etc/hosts at startup, before running the real program
• add entries to /etc/hosts when you run the container with the --add-host option.