It changed hostname on my computer?

After installing Docker on Apple OS X 10.13, I noticed that in Terminal shell, my prompt (which has the hostname in it) is now showing a weird string instead of my Mac name. I then noticed that PiHole, which I’m running in this container is showing the same string as its Hostname. Why/where is the Docker resetting my computer name? Oddly, the name shown in System Preferences network sharing preference pane is still normal.