Once node (and npm) is available, you of course need to get the parsoid and visual_editor extensions. A quick <code>npm install</code> in the parsoid directory sets up all the node machinery.
To have it run continuously, you might want to use the 'forever' module, but that is just a node way of monitoring processes. You might want to simply use tools build for the purpose like [[monit]]
<source lang="bash">
npm install -g forever