Useful Ansible plays for Raspberry Pis

February 2, 2024 6 min read

I run a small cluster of 4 Raspberry Pis at home for experimenting. Apart from containerizing certain things, there are routine maintainance operations like updating installed packages or monitoring ram/disk usage that I have some simple Ansible playbooks for.

Quick setup notes:

  • I'm not diving deep on Ansible here. Just sharing some things I use. I'm assuming some knowledge of what Ansible is and how it works.
  • Here's a quick setup snippet on how I have 4 Rapsberry Pis grouped and their names. Note: I have ssh keys set up in ~/.ssh/config and I'm VPN'd to each of these via Tailscale. So no key setup in this post and the VPN is how I can connect directly to these hostnames.

ansible.cfg

1[defaults]
2inventory = pis.ini
3stdout_callback = yaml

pis.ini

1[pis]
2raspberrypi-1
3raspberrypi-2
4raspberrypi-3
5raspberrypi-4

Ok, now on to the first playbook, which I use to keep Pi OS up to date:

pis_update.yml

1---
2- name: Update Installed Packages
3  hosts: pis
4  become: true
5  tasks:
6    - name: Update apt cache
7      apt:
8        update_cache: true
9        cache_valid_time: 86400
10
11    - name: Upgrade all packages to the latest version
12      apt:
13        upgrade: dist
14        autoremove: true
15        autoclean: true

The two tasks here are easy to follow - update the apt cache and then upgrade all installed packages.

Next I have a nice way to get reports on each of my Pis, but one quick setup playbook before we do that:

pis_setup.yml

1---
2- name: Install speedtest-cli
3  hosts: pis
4  become: true
5  tasks:
6    - name: Install speedtest-cli
7      ansible.builtin.apt:
8        name: speedtest-cli
9        state: present

Installing speedtest-cli will give us a chance to run speed tests for each of the Pis in the cluster.

And now the playbook for gathering reports:

pis_report.yml

1---
2- name: Disk usage report
3  hosts: pis
4  become: yes
5  tasks:
6    - name: Get disk usage
7      ansible.builtin.setup:
8        gather_subset:
9          - "!all"
10          - "min"
11        filter: "ansible_mounts"
12    - name: Print disk usage
13      ansible.builtin.debug:
14        msg: |
15          {% for mount in ansible_mounts %}
16          Mount: {{ mount.mount }}
17          Total Size: {{ mount.size_total | human_readable }}
18          Free Space: {{ mount.size_available | human_readable }}
19          Used Space: {{ (mount.size_total - mount.size_available) | human_readable }}
20          {% endfor %}
21
22- name: Memory report
23  hosts: pis
24  become: true
25  tasks:
26    - name: Get memory report
27      command: free -h -t --giga
28      register: free_memory
29    - name: Print memory report
30      debug:
31        msg: "{{ free_memory.stdout_lines }}"
32
33- name: Pi models report
34  hosts: pis
35  become: yes
36  tasks:
37    - name: Get Pi Models
38      shell: cat /proc/device-tree/model | tr -d '\0'
39      register: pi_model
40    - name: Print Pi Models
41      debug:
42        msg: "{{ pi_model.stdout_lines }}"
43
44- name: OS versions report
45  hosts: pis
46  gather_facts: true
47  tasks:
48    - name: Get OS Version
49      command: cat /etc/os-release
50      register: os_release
51    - name: Extract PRETTY_NAME
52      set_fact:
53        pretty_name: "{{ os_release.stdout | regex_search('PRETTY_NAME=(.*)', '\\1') }}"
54    - name: Print OS Version
55      debug:
56        msg: "{{ pretty_name }}"
57
58- name: Speed test report
59  hosts: pis
60  become: false
61  tasks:
62    - name: Execute speedtest-cli
63      ansible.builtin.command: speedtest-cli --simple
64      register: speedtest_result
65
66    - name: Print speed test results
67      ansible.builtin.debug:
68        msg: "{{ speedtest_result.stdout }}"

We have the following five plays running here:

  • Disk usage report
  • Memory report
  • Raspberry Pi models report
  • OS versions report
  • Speed test report

I have my Raspberry Pis named raspberrypi-1, raspberrypi-2, raspberrypi-3, and raspberrypi-4, which each show up in each of these reports. I've also recently reset these so the memory and disk usage will both be low in these reports.

For Disk usage report:

1ok: [raspberrypi-1] =>
2  msg: |-
3    Mount: /
4    Total Size: 14.32 GB
5    Free Space: 7.39 GB
6    Used Space: 6.93 GB
7    Mount: /boot
8    Total Size: 254.99 MB
9    Free Space: 222.27 MB
10    Used Space: 32.72 MB
11ok: [raspberrypi-2] =>
12  msg: |-
13    Mount: /
14    Total Size: 28.97 GB
15    Free Space: 22.14 GB
16    Used Space: 6.83 GB
17    Mount: /boot
18    Total Size: 254.99 MB
19    Free Space: 223.07 MB
20    Used Space: 31.91 MB
21ok: [raspberrypi-3] =>
22  msg: |-
23    Mount: /
24    Total Size: 28.97 GB
25    Free Space: 22.16 GB
26    Used Space: 6.81 GB
27    Mount: /boot
28    Total Size: 254.99 MB
29    Free Space: 223.18 MB
30    Used Space: 31.80 MB
31ok: [raspberrypi-4] =>
32  msg: |-
33    Mount: /
34    Total Size: 28.97 GB
35    Free Space: 21.40 GB
36    Used Space: 7.57 GB
37    Mount: /boot
38    Total Size: 254.99 MB
39    Free Space: 222.90 MB
40    Used Space: 32.09 MB

For Memory report:

1ok: [raspberrypi-1] =>
2  msg:
3  - '               total        used        free      shared  buff/cache   available'
4  - 'Mem:            909M        183M        198M        0.0K        526M        661M'
5  - 'Swap:            99M         38M         61M'
6  - 'Total:          1.0G        222M        260M'
7ok: [raspberrypi-2] =>
8  msg:
9  - '               total        used        free      shared  buff/cache   available'
10  - 'Mem:            909M        148M        184M        0.0K        576M        696M'
11  - 'Swap:            99M         10M         89M'
12  - 'Total:          1.0G        159M        273M'
13ok: [raspberrypi-3] =>
14  msg:
15  - '               total        used        free      shared  buff/cache   available'
16  - 'Mem:            909M        147M        193M        0.0K        568M        697M'
17  - 'Swap:            99M        9.0M         90M'
18  - 'Total:          1.0G        156M        284M'
19ok: [raspberrypi-4] =>
20  msg:
21  - '               total        used        free      shared  buff/cache   available'
22  - 'Mem:            1.8G        168M        592M        0.0K        1.1G        1.6G'
23  - 'Swap:            99M        1.0M         98M'
24  - 'Total:          1.9G        170M        691M'

For Pi models report

1ok: [raspberrypi-1] =>
2  msg:
3  - Raspberry Pi 3 Model B Rev 1.2
4ok: [raspberrypi-2] =>
5  msg:
6  - Raspberry Pi 3 Model B Rev 1.2
7ok: [raspberrypi-3] =>
8  msg:
9  - Raspberry Pi 3 Model B Rev 1.2
10ok: [raspberrypi-4] =>
11  msg:
12  - Raspberry Pi 4 Model B Rev 1.1

For OS versions report:

1ok: [raspberrypi-1] =>
2  msg:
3  - '"Debian GNU/Linux 11 (bullseye)"'
4ok: [raspberrypi-2] =>
5  msg:
6  - '"Debian GNU/Linux 11 (bullseye)"'
7ok: [raspberrypi-3] =>
8  msg:
9  - '"Debian GNU/Linux 11 (bullseye)"'
10ok: [raspberrypi-4] =>
11  msg:
12  - '"Debian GNU/Linux 11 (bullseye)"'

For Speed test report:

1ok: [raspberrypi-1] =>
2  msg: |-
3    Ping: 23.252 ms
4    Download: 5.31 Mbit/s
5    Upload: 5.20 Mbit/s
6ok: [raspberrypi-2] =>
7  msg: |-
8    Ping: 26.886 ms
9    Download: 4.24 Mbit/s
10    Upload: 3.54 Mbit/s
11ok: [raspberrypi-3] =>
12  msg: |-
13    Ping: 21.114 ms
14    Download: 12.47 Mbit/s
15    Upload: 8.30 Mbit/s
16ok: [raspberrypi-4] =>
17  msg: |-
18    Ping: 23.271 ms
19    Download: 22.04 Mbit/s
20    Upload: 9.84 Mbit/s

I think it's a cool little playbook for gathering info across a cluster of Raspberry Pis. Also interesting to note the speed jump on raspberrypi-4, which is the only model 4 of the cluster. The rest are 3s.

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