DevOps: Puppet, Docker, and Kubernetes

Setting facts as environment variables

Another handy way to get information into Puppet and Facter is to pass it using environment variables. Any environment variable whose name starts with FACTER_ will be interpreted as a fact. For example, ask facter the value of hello using the following command:

[root@cookbook ~]# facter -p hello
Hello, world

Now override the value with an environment variable and ask again:

[root@cookbook ~]# FACTER_hello='Howdy!' facter -p hello
Howdy!

It works just as well with Puppet, so let's run through an example.

How to do it...

In this example we'll set a fact using an environment variable:

1. Keep the node definition for cookbook the same as our last example:

   node cookbook {
     notify {"$::hello": }
   }

2. Run the following command: ...