Every example IP in the previous article was 203.0.113.10. That is not a number I invented, and it is not a real server. It comes from TEST-NET-3, one of three IPv4 ranges the IETF reserved specifically so that technical writers have addresses they can safely put in front of readers.
You have a fresh Ubuntu box and a root password in an email. Everything you know about infrastructure says configuration should be codified, reviewed, version-controlled and applied by a tool. And none of that helps yet, because Ansible needs SSH access, a user, and a Python interpreter — none of which exist.
Take a requirement that sounds unremarkable: upgrade twelve web servers with no downtime. One at a time, drained from the load balancer first, health-checked before returning to service, and the whole thing stops if more than a quarter of them fail.
Four packages, one playbook. This should be a boring afternoon, and it mostly is — except for one ordering problem that breaks almost every tutorial on the subject, in a way that only shows up on a genuinely fresh server.
So let me start there, because if you understand it the rest is just YAML.
If you came here looking for how to install open-source Puppet on a current Ubuntu, the short answer is that you can't, and it is not your fault for not knowing. The instructions everyone wrote — add deb.puppetlabs.com, install puppet-agent — stopped producing new versions in early 2025.
Here is the Dockerfile almost everyone writes first:
Every year, on schedule, someone writes the obituary for self-hosted email. The argument is always the same shape: Gmail and Microsoft control the inbox, residential and small-VPS IP ranges are pre-blocked before you've sent a single message, and the only rational move is to hand your mail to a SaaS provider and get on with your life.
For decades, SSH has been the universal tool for managing Linux servers.
Need to restart a service?
SSH.
Need to update PHP?
SSH.
Need to fix a configuration file?
SSH.
Need to investigate a production problem at 2 a.m.?
SSH.
There is nothing inherently wrong with SSH.
Most developers begin their careers thinking almost exclusively about applications.
Over the last decade, software development has become increasingly dependent on Software-as-a-Service (SaaS) platforms. Source code is stored on hosted Git providers, project management takes place in cloud applications, documentation lives in online knowledge bases, and monitoring data is collected by third-party observability services.