Introduction

While some concepts in Engineering should not be brought back to home, I find that Ansible was one of the few tools that is actually useful in a home environment.

Why Ansible?

Ansible is a powerful automation tool that can help manage and configure systems efficiently. Another key important aspect commonly missed out is documentation. In the past, I would usually SSH into my home server and make changes directly. If I remember to document it, I would save code snippets into a README.md or obsidian note. However, this approach is prone to human error and can lead to inconsistencies over time. Most forms of IaC (Infrastructure as Code) tools are self documenting, as the code itself serves as documentation.

Setup and Configuration

Before diving into use cases, it's important to set up Ansible properly for a home environment. The configuration is straightforward and makes running playbooks much more convenient.

I keep two files in the project directory: an ansible.cfg pointing to my inventory file and enabling become_ask_pass so it prompts for sudo passwords rather than storing credentials (security first, even at home), and an inventory.ini with at least localhost ansible_connection=local so playbooks run locally without SSH overhead. With those in place, ansible-playbook playbook.yml just works.

Use Cases

System configuration

I am using a consumer intel CPU with a stock cooler for my homelab. As I don't expect it to run heavy workloads, I don't need it to run at full power. I set the PL1 and PL2 power limits through Ansible rather than using the intel-undervolt tool. This way, if I ever need to re-install the OS or set up a new server, I can easily apply the same configuration without having to remember the exact commands or settings.

The playbook validates that PL1 and PL2 values fall within acceptable ranges (hard lower/upper limits) and ensures PL2 >= PL1 before applying them. It then writes to the sysfs powercap interfaces to set sustained and burst power limits, and creates a systemd service for persistence across reboots.

It's easy to make mistakes when setting raw power values -- adding one extra zero can be disastrous. With Ansible, I can specify values like 65W and 90W instead of 65000000 and 90000000, and the validation layer catches out-of-range inputs before they get applied.

Restic setup

Restic is a great backup tool that can be used to back up data to various locations. The backup scripts are manually written, but the cron jobs and log rotation are managed by Ansible. If the below process were to be done manually, it would be prone to human error and inconsistencies, as multiple files are involved, such as cron jobs, log rotation configuration, and the backup scripts themselves.

The playbook ensures restic is installed, makes the backup scripts executable, sets up two daily cron jobs (one for immich data at 2 AM, one for documents at 3 AM), and configures logrotate to keep 21 days of compressed logs with daily rotation.

Conclusion

As you add more services and configurations to your home environment, the benefits of using Ansible become even more apparent. It helps maintain consistency, reduces the risk of human error, and serves as documentation for your setup. Whether you're managing a single server or multiple devices, Ansible can streamline your home automation tasks effectively.

The full version with the complete playbook examples is on my blog.