As a pythonista, I am a huge fan of the plumbum library as a replacement for bash. It makes it very straightforward to run a sequence of *nix commands, but you get all the simplicity and power of the python language in terms of loops and functions and so forth. These days, I do all my server management and deployment scripts with python/plumbum.
And while simple is great, the necessary features not included in OP's scripts is that I want to spin up the new instance in parallel, verify it is running correctly, and then switch nginx or the load balancer to point to the new server. You are less prone to break production and you get zero downtime deploys.
How do you deal with plumbum not being a builtin module? Do you install it system-wide? This currently holds me back from using sh (the Python lib) for maintaining my servers, especially if I need it with root.
That's not a big deal for me since I only am running a handful of servers. I install it system-wide during initial setup of a new server. Plumbum has the ability to run remote shell commands as well, so I have a script that can login to a new remote machine and do that initial setup.
And while simple is great, the necessary features not included in OP's scripts is that I want to spin up the new instance in parallel, verify it is running correctly, and then switch nginx or the load balancer to point to the new server. You are less prone to break production and you get zero downtime deploys.