# Ansible template data structure for dnsmasq.conf? **URL:** \ **Category:** Get Help\ **Created:** [February 24, 2025, 11:55am UTC](https://forum.ansible.com/t/ansible-template-data-structure-for-dnsmasq-conf/40586 "2025-02-24T11:55:55Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![microlinux](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/microlinux/32/2968_2.png) [@microlinux](https://forum.ansible.com/u/microlinux)\ **Post date:** [February 24, 2025, 11:55am UTC](https://forum.ansible.com/t/ansible-template-data-structure-for-dnsmasq-conf/40586/1 "2025-02-24T11:55:55Z")
Hi, I’m currently writing an Ansible role for automatically setting up Dnsmasq on my routerboard running Rocky Linux. Here’s the actual `dnsmasq.conf` which I setup manually: ```auto # /etc/dnsmasq.conf domain-needed bogus-priv interface=enp2s0 dhcp-range=192.168.2.100,192.168.2.200,24h local=/microlinux.lan/ domain=microlinux.lan expand-hosts #server=208.67.222.123 #server=208.67.220.123 #server=8.8.8.8 #server=8.8.4.4 server=1.1.1.1 server=1.0.0.1 no-resolv log-facility=/var/log/dnsmasq.log address=/proxy.microlinux.lan/192.168.2.1 address=/rocky-el8.microlinux.lan/192.168.2.10 dhcp-host=50:65:F3:4E:DA:77,alphamule,192.168.2.2 dhcp-host=B0:83:FE:90:4D:64,sandbox,192.168.2.3 dhcp-host=68:54:5A:B2:D0:81,dell-xps,192.168.2.4 dhcp-host=D0:37:45:24:61:BD,44:37:E6:DA:44:72,gustave,192.168.2.5 dhcp-host=3C:DC:BC:00:FB:97,smartphone-nico,192.168.2.6 dhcp-host=AC:AF:B9:D6:93:FA,smartphone-clothilde,192.168.2.7 dhcp-host=52:54:00:00:00:01,testbox-el8,192.168.2.10 dhcp-host=52:54:00:00:00:02,testbox-el9,192.168.2.11 dhcp-host=D4:85:64:B2:B2:1B,oldmule,192.168.2.249 dhcp-host=00:22:64:8A:4C:C2,nestor,192.168.2.250 dhcp-host=00:0D:B9:4B:5B:5C,squidbox,192.168.2.251 dhcp-host=10:62:E5:D4:95:60,hp-officejet,192.168.2.252 dhcp-host=00:11:32:26:63:A5,nas,192.168.2.253 ``` And here’s the corresponding `/etc/hosts` file: ```auto # /etc/hosts 127.0.0.1 localhost.localdomain localhost 192.168.2.1 proxy.microlinux.lan proxy 192.168.2.2 alphamule 192.168.2.3 sandbox 192.168.2.4 dell-xps 192.168.2.5 gustave 192.168.2.6 smartphone-nico 192.168.2.7 smartphone-clothilde 192.168.2.10 testbox-el8 192.168.2.11 testbox-el9 192.168.2.249 oldmule 192.168.2.250 nestor 192.168.2.251 squidbox 192.168.2.252 hp-officejet 192.168.2.253 nas 192.168.2.254 wifi ``` For now my playbook for Ansible looks like this: ```auto - name: Configure hosts file ansible.builtin.template: src: hosts.j2 dest: /etc/hosts - name: Install Dnsmasq ansible.builtin.dnf: name: dnsmasq state: present - name: Enable and start Dnsmasq ansible.builtin.service: name: dnsmasq enabled: true state: started - name: Configure Dnsmasq ansible.builtin.template: src: dnsmasq.conf.j2 dest: /etc/dnsmasq.conf notify: Restart Dnsmasq - meta: flush_handlers ``` Here’s the `hosts.j2` file: ```auto # /etc/hosts 127.0.0.1 localhost.localdomain localhost {{address_lan}} {{hostname}}.{{domain_lan}} {{hostname}} ``` And here’s the `dnsmasq.conf.j2` file (using a different network for testing purposes): ```auto # /etc/dnsmasq.conf domain-needed bogus-priv interface={{interface_lan}} dhcp-range=192.168.3.100,192.168.3.200,24h local=/{{domain_lan}}/ domain={{domain_lan}} expand-hosts server={{dns1}} server={{dns2}} no-resolv log-facility=/var/log/dnsmasq.log address=/{{hostname}}.{{domain_lan}}/{{address_lan}} ``` As you can see in the example above, I have a series of clients (`sandbox`, `dell-xps`, `gustave` and so on) each with a corresponding local IP address as well as a MAC address. > Note that the client `gustave` has two MAC addresses since it can connect by wired interface or by wireless. Now I could very well hardcode all these clients into my `dnsmasq.conf.j2` and `hosts.j2` templates. > There’s a slight redundancy here, due to the fact that Dnsmasq needs hostnames in `/etc/hosts`. But I think a more elegant solution would be to use variables. And now I wonder how the data structure could look like here. I bluntly admit I’m not very proficient with nested dictionaries, nested lists, lists of dictionaries and dictionaries of lists etc. How could I write a data structure for these client machines to put in my template ? Cheers, Niki ---
**Author:** ![kristianheljas](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/kristianheljas/32/7702_2.png) [@kristianheljas](https://forum.ansible.com/u/kristianheljas)\ **Post date:** [February 24, 2025, 12:51pm UTC](https://forum.ansible.com/t/ansible-template-data-structure-for-dnsmasq-conf/40586/2 "2025-02-24T12:51:31Z")
You are looking for list of dictionaries . Your data structure could look like: ```yaml static_dhcp_leases: - mac: "50:65:F3:4E:DA:77" hostname: alphamule ip: 192.168.2.2 - mac: "B0:83:FE:90:4D:64" hostname: sandbox ip: 192.168.2.3 ``` Then you could use [for loop](https://jinja.palletsprojects.com/en/stable/templates/#for) to generate the result: ```auto {% for lease in static_dhcp_leases %} dhcp-host={{ lease.mac }},{{ lease.hostname }},{{ lease.ip }} {% endfor %} ``` ---
**Author:** ![microlinux](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/microlinux/32/2968_2.png) [@microlinux](https://forum.ansible.com/u/microlinux)\ **Post date:** [February 24, 2025, 4:32pm UTC](https://forum.ansible.com/t/ansible-template-data-structure-for-dnsmasq-conf/40586/3 "2025-02-24T16:32:28Z")
Thank you very much !