REPL on the Compute notes?

We had an issue this morning, same symptoms as described over in…

… except this time it was persistent. I solved it by terminating the node. It returned 500 on requests, but for some reason the NLB was perfectly fine with this and didn’t terminate it automatically.

We’re now looking at more liberal sprinkling of casts throughout the code to catch it next time when/if it happens, but this seems a bit like black box engineering. It would have been nice to have a more direct way to inspect the state of the machine.