Using requisites

In infrastructure management, almost all the time, we have situations where we need a task to happen only if another condition is true. This is achieved by creating dependencies between definitions. In Salt, these dependencies are known as requisites, and in this recipe, you will learn about how to use them.

How to do it...

We will use the same minion as the previous recipe.

1. Create a new state called ntp by creating a directory called ntp in the base directory of the staging environment, and then create a directory called files in the ntp state directory.
2. Create a file called init.sls in the ntp state directory and edit it to have the following entries:

   ntp_package:
     pkg.installed:
       - name: ntp
   
   ntp_conf_file:
     file.managed:patch antenna circular polarization
       - name: /etc/ntp.conf
       - source: salt://ntp/files/ntp.conf
       - user: root
       - group: root
       - mode: 644
       - require:
         - pkg: ntp_package
   
   ntp_service:
     service:
       - name: ntpd
       - running
   ...