They'll clean up instances that aren't doing enough for them to notice, even -- I used to run an XMPP server on one, used daily but not with many users, and they kept shutting it down at random multi-day intervals with little warning. Stopped using it.

I wrote a script to simulate a variable workload when the load averages dipped so that I could keep my mostly-idle VMs running. It felt like a waste of energy but the VMs are in short supply which meant that Oracle has already decided that their servers will generate heat regardless of my actions: if I wasn't burning enough CPU cycles they would find someone who would.

Load average of ~30% per core seems to have been enough to repel the elephants.

They state that here and it's been stated there in the several years I've run Always Free VM's there: https://docs.oracle.com/en-us/iaas/Content/FreeTier/freetier...

Some people say that doesn't apply to PAYG users, I do not know about that for sure, I am a PAYG user since 2021 and have not experienced any reclamation issues.

I use mine as a reverse proxy for accessing my home plex via tailscale and a few other small purposes. Noticed they would turn it off at random too. Setup a script to SSH into it every 5 minutes and that stopped it - it's been up for a couple years now.