Cross-posting this from Lemmy world where it seems my post coming from piefed.ca is not federating.
This is something that seems to happen randomly to my little RaspberryPi 4B homeserver, like once every few months maybe.
What happens is that out of nowhere (meaning I didn't make any change to config or installation) I cannot reach any services I host on it (i.e. Jellyfin, Anchor notes...). I cannot access it via SSH at all, connection keeps timing out.
Ping however gives a signal. I can see/hear its running and doing something, since I hear the external HDD working. It is running headless and I have no monitor and/or keyboard I could connect.
So far my only way out is to just switch its power off, which is obviously not good for the hard drive. It has happened now like half a dozen times over the past few years, so I am wondering what a better way is to handle this. This was on RPI OS and now its happening on DietPi, so seems not related to the OS version.
I tried sending a shutdown signal via SSH but that also just times out, so how do I get it to shutdown properly?
Secondly, what kind of logs could I look at or start collecting to make sense of this?
This happened when my sshd dameon did not start or died. You could use systemctl status to check it.
It has also happened when my white listed static IP for my machine that I access the server with changed. Do you have a default DROP policy?
Timing out indicates that either the sshd service doesn't exist or is unreachable (but not blocked).
Check the dmesg for all sshd notifications and maybe you find why it is crashing (if the service is dead)