I was working with a C.H.I.P and the SSH host keys were regenerating each boot after upgrading to Stretch. This caused a host key mismatch every time. It turns out /etc/rc.local was a script which checked for the presence of SSH host keys, including DSA, and if found all of them it replaced itself with /etc/rc.local.orig, which is the stock does-nothing script. If it didn’t find all of them, it would delete any existing keys and regenerate all of them.
I still don’t understand why this produced the behavior it did, because the script did succeed in producing DSA keys, but replacing the weird /etc/rc.local with the /etc/rc.local.orig that just exit 0s seems to have solved the problem.
I have no experience with the subject that you discussed here, but I recently remembered your blog and was reading through it. Seeing the older entries especially reminded me of how different the world was ten years ago. A lot has changed since then, especially in politics and Linux! I use Linux Mint now (user-friendly Linux FTW)
Additionally, I don’t know if you remember an old Linux game named Slune. You would really like it, though it’s buggy. I managed to install it on the latest version of Mint, some of my instructions are described here (https://forums.linuxmint.com/viewtopic.php?f=225&t=265563)
Yep, things seem to have gotten a lot better-documented. I don’t remember it, but that game does indeed look colorful!