Deploying DNS zone files with Ansible can be annoying to set up if we want the SOA serial to be incremented according to the RFC, which requires a serial in the YYYYMMDDxx format, where YYYYMMDD is the deployment date and xx a daily increment.

The simplest way I found to do it with Ansible is the following variables in your role’s defaults/main.yml file :

today: "{{ lookup('pipe','date +%Y%m%d') }}"
epoch_midnight: "{{ lookup('pipe','date --date={{ today }} +%s') }}"
now: "{{ lookup('pipe','date +%s') }}"
num_secs: "{{ now|int - epoch_midnight|int }}"
day_incr: "{{ (num_secs|int * 99 / 86400)|int }}"
dns_serial : "{{ today }}{{ day_incr }}"

This provides a {{ dns_serial }} variable that you can use in your zone template. The daily increment part is calculated depending on the number of seconds elapsed since today at 00:00:00, multiplied by 99 divided by 86400, which allows for 99 increments in a given day. You may need to wait a few minutes before two deployments of the zone file for the increment to update, but it’s much easier than parsing the previously existing SOA serial.

Hope this helps.