Author here.

- The article uses systemd for process monitoring rather than PM2 since it's built into the OS.

- The article uses HAProxy as a load balancer.

- Ansible playbooks, Dockerfiles, and the AWS API are all mentioned in the opening section of the article. Serverless sounds fine too. Personally I use http://mikemaccana.com/images/work/screenshots/firework-0.pn... which I made using the AWS API. Either way, you will need some logic to capture inside these tools. Rather than write an article on Dockerfiles, Ansible playbooks, or the AWS or DO APIs, the article covers the devops basics one needs to know before using these tools.

'Use ${TOOL}' doesn't help you create or understand the contents of ${TOOL}s Dockerfile.