Get random seed from variable

Trying to avoid all ansible-deployed apache2 vhosts starting to update their php-apps at once, I want to use the FQDN as random seed for cron. I think of something like this, which does not work:

- name: get random seed from variable
  debug:
    msg: "29") }}"

Is there a way to get a variable nested into another one?

The following works fine, but is not sufficcient, as the '''inventory_hostname''' is the same for all vhosts.

- name: get random seed from variable
  debug:
    msg: "29"