I"m relatively new to self-hosting and I have an instance on Oracle cloud with a few apps that I run. More recently this instance is becoming unresponsive every 30 minutes or so. It becomes impossible to SSH to it and any connection to it is dropped. Oracle Cloud says that it is unresponsive, forcibly rebooting it fixes the issue until it becomes unresponsive again in 30 minutes. I believe the most major thing I did since this started was installing Java and doing an "apt update" followed by "apt upgrade" after many months of not doing it. I have tried to turn off every service that I have running using pm2 and systemctl. No luck. Are there any tools that I can use to better understand why it is freezing like that?

Edit: I ran the following command systemctl --type=service --state=running And noticed there was a Gnome Display Manager that was running and I wasn't using it. After disabling this service with systemctl disable [servicename] The server stopped crashing. Thanks for all the replies!