I have the following setup at home:
- 3 RPis connected to router via ethernet. They have more than enough power supplies and are headless.
- RPi #1 (very old model) runs pihole and acts as DHCP server.
- RPi #2 (very old model) runs some lightweight web services.
- RPi #3 (model 4) runs some heavier web services.
- IP addresses are static as configured in RPi #1's pihole DHCP server. The router's DHCP server is switched off accordingly.
The issue I've been having for a couple of months is the following: the third RPi becomes irresponsive often and seems to freeze SSH access to any of the other RPis. Freeze as in I can ping any of the RPis fine but cannot ssh into any of them—terminal gets stuck without showing any output. RPi #3's web services become inaccessible, but the other two RPi's web services are working fine and are accessible, yet I cannot ssh into them. I pull the plug on RPi #3 and I can then ssh into the other two RPis fine. Interestingly, even when everything is frozen, I can use WireGuard on RPi #3 fine, so this RPi hasn't crashed and it has a network connection, even though all web services are seemingly down.
I use Mac OS over wifi to connect to the RPis.
I also activated the watchdog for the problematic RPi #3 but no luck.