Setting up home NAS - Part 7 - Automate using Ansible

This is the continuation of the "Setting up home NAS" series. Better read the below posts to get context.

Setting up home NAS - Part 0 - RAID v/s Backup rsync v/s Raspberry Pi v/s Cloud Storage for Youtuber in the year 2020

Setting up home NAS - Part 1 - Scientific debugging to get USB drive visible as \\share in network

Setting up home NAS - Part 2 - PowerShell arrange media date bases files into YYYY\MM\DD folders

Setting up home NAS - Part 3 - Dealing with duplicates

Setting up home NAS - Patt 4 - Raspberry Pi to build locally redundant NAS for home

Setting up home NAS - Part 5 - e-mailing rsync report

Setting up home NAS - Part 6 - Raspberry Pi as Media Server using Plex

Setting up home NAS - Part 7 - Automate using Ansible

Introduction

Previous posts have manual instructions to set up the Raspberry Pi to function as a NAS and Plex media server. As we all know manual steps are error-prone and difficult to replicate. This post is about automating the deployment and manual configuration steps.

Architecture

There are different approaches to automating the machine configuration and software deployment.

The easy way is to simply write scripts and get them executed in the target machine itself. Here target is Raspberry Pi and Ansible supports this method and lets us install it on Raspberry Pi.

Secondly, agent-based¹ where we first manually install an agent software that polls the central repository of configuration. In case there are any changes, it will apply those to the host machine where it is running.

Another way is the opposite of agent-based. A controller machine pushes the changes to the target machine using some remoting technology. Here the target is Raspberry Pi

Here we are using an agentless method using a tool called Red Hat Ansible². Ansible is a well-known tool in IT automation workflows.

SSH to Pi with keys 

Since there is no agent to listen in, the controller machine needs to use a way to remote into the target machine to be configured. Ansible uses SSH³ to do the same.

The default way is to run the Ansible scripts and it will ask for login details. For Raspberry to set up that is fine. But there are ways to avoid it by using the SSH public-private key pairs.

There are clearly documented ways to establish a passwordless login to RasPi⁴ using SSH keys. But there are chances of things going wrong and troubleshooting SSH keys to authenticate should be a separate post on its own.

Installing Ansible

It requires Python to be installed. The installation of Ansible is straightforward and well documented⁵.

Source code

Enough theory. Since it involves scripts that can be enhanced later, it is better to keep in a source control repository. Below is the source code repo link to GitHub.

https://github.com/joymon/ansible-raspberry-home-nas-plex

The readme.md is pretty much updated.

One thing pending is the setting up of the user password that is used to access the shared path from Raspberry.

It will be added soon and updates will be pushed to the same repo. 

Ansible in Windows v/s Linux

One drawback is that Ansible is not very compatible with Windows as a controller. So we have to use the WSL2 feature of Windows to manage the target Raspberry Pi.

Reference

• ¹ - https://dzone.com/articles/part-ii-choosing-the-right-infrastructure-as-code
• ² - https://www.ansible.com/
• ³ - https://docs.ansible.com/ansible/latest/inventory_guide/connection_details.html
• ⁴ - https://www.raspberrypi.com/documentation/computers/remote-access.html#secure-shell-from-windows-10
• ⁵ - https://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html
• ⁶ - https://docs.ansible.com/ansible/latest/os_guide/windows_faq.html#can-ansible-run-on-windows