Setting up PM2 to manage Node.js processes

We have two servers, svc-notes and svc-userauth, configured so we can run the two services making up the Notes application stack. A big task remaining is to ensure the Node.js processes are properly installed as background processes.

To see the problem, start another command window and run these commands:

$ multipass restart svc-userauth
$ multipass restart svc-notes

The server instances were running under Multipass, and the restart command caused the named instance to stop and then start. This emulates a server reboot. Since both were running in the foreground, you'll see each command window exit to the host command shell, and running multipass list again will show both instances in the Running state. The big takeaway is that both services are no longer running.

There are many ways to manage server processes, to ensure restarts if the process crashes, and so on. We'll use PM2 (http://pm2.keymetrics.io/) because it's optimized for...