Trending on MSDN: Kernel Panic - Not Syncing: Out of Memory and no Killable Processes

Question

I have a recently created VM. It's an Ubuntu VM, and I've not done anything to it besides installing Docker.

I'm running two Docker containers:

1. Portainer
2. A small dotnet core application

After setting this up, I had a look in HTOP to see the memory and CPU usage, and I found they were both low.

Today I could not reach the VM over SSH, so I looked at the log under the "Serial console" tab in Azure Portal. I can see that it for some reason it ran out of memory and started killing off all the processes, until it finally says, "Kernel panic - not syncing: Out of memory and no killable processes".

Any ideas what this might be?