I have a Raspberry Pi 3b with Octoprint v1.3.5. Twice now Octoprint has automatically downloaded updates and when I try to access the pi again it becomes randomly unresponsive. The Octoprint webpage will load only partially if at all. Usually the browser simply spins indefinitely. SSH works intermittently.
Upon connecting with an SSH session it will generally simply hang within a few seconds to minutes, sometimes in the middle of the logon script. Sometimes it will temporarily recover, sometimes not. Sometimes I can disconnect and reconnect via SSH, sometimes the "login as" prompt never appears. Running top shows that barely any resources are being used. I tested power across pins 2 and 6 and saw 4.94v, which to my understanding should be well within tolerances, especially when the pi isn't doing anything.
The most frustrating part is that even when it's completely unresponsive to SSH and web requests it will happily respond to pings with single digit millisecond response times. The first time this occurred I accessed it with a keyboard and monitor and everything was fine. There were no obvious issues. I've not tried that yet as it's a bit of a hassle to get to the extra hardware.
Are there any logs I can check which would point me in the right direction? Diagnostic tools to install? Other suggestions?
EDIT: I suspect I've found the issue, or at least a contributing factor. There appear to be 10 instances of the octoprint server running at any given time. I'm not sure exactly how that leads to it locking up, but if enough of them try to respond to web requests, that could certainly lead to all of the available ram being commandeered to the point of unresponsiveness. I've no idea why multiple instances are being started or how to stop them (killing one seems to kill them all and restarting the service starts 10 instances).