[clinta]

I maintain a couple of docker network plugins. One day Docker devs decided that they would bundle an internal DNS resolver inside the docker daemon and take over the resolv.conf in every container. But here's the most amazing part. It only did this for custom networks. If you just used docker out of the box you would never see this. But if you used custom networks, and custom network drivers, it did this. And the docker team refused to allow any configuration options to disable it.

I now maintain a daemon who's sole job is to undo Docker's meddling with resolv.conf until I can get the bandwidth to explore migrating to Kubernetes.

[Spivak]

I ran into a piece of software that was basically impossible to containerize because of this weirdness.

It wanted to ‘mv’ over resolv.conf but couldn’t so we had to run it outside the container because it was proprietary and we couldn’t readily modify it.