Quick start Tutorial

Using the file datasource as configured earlier we can add our data to YAML files under the directory specified in :docroot, which we set to /var/lib/jerakia

It’s recommended that you read Jerakia Lookup Basics to understand the structure and behaviour of a Jerakia lookup

Understanding the file datasource

When using the file datasource, the :searchpath is evaluated to determine which files to scan and elements of the scope object can be interpolated into the file paths. By default, Jerakia will search for the key in a filename corresponding to the namespace. So, lets review our lookup object from earlier, it has the following settings configured…

:format => :yaml,
:docroot => "/var/lib/jerakia",
:searchpath => [
  "hostname/#{scope[:fqdn]}",
  "environment/#{scope[:environment]}",
  "common"
 ]

If our scope contains the following

"environment" => "development",
"fqdn"        => "host011.example.com"

Then when we search for the key port in the apache namespace (eg: apache::port) then Jerakia will scan the following files until it encounters the key port:

/var/lib/jerakia/hostname/host011.example.com/apache.yaml
/var/lib/jerakia/environment/development/apache.yaml
/var/lib/jerakia/common/apache.yaml

The astute among you might have noticed that the search is done in a common directory rather than common.yaml as you would expect with hiera. To understand why that is the case read File datasource, to explain the functioning and differences between hiera and jerakia. To get the above debug output yourself read the Debug Guide

Add data to the searchpath

Let’s start off by adding the port value to our searchpath

$ mkdir -p /var/lib/jerakia/common
$ vim /var/lib/jerakia/common/apache.yaml

---
port: 8080

Next: Running Jerakia from the command line