fuel-web/docs/develop/fuel_settings.rst

Using Fuel settings

Fuel uses a special way to pass setting from Nailgun to Puppet manifests. Before the start of deployment process Astute uploads all settings, each server should have to the file /etc/astute.yaml placed on every node. When Puppet is run facter reads this file entirely into a single fact $astute_settings_yaml. Then these settings are parsed by parseyaml function at the very beginning of site.pp file and set as rich data structure called $fuel_settings. All of the setting used during node deployment are stored there and can be used anywhere in Puppet code. For example, single top level variables are available as $::fuel_settings['debug']. More complex structures are also available as values of $::fuel_settings hash keys and can be accessed like usual hashes and arrays. There are also a lot of aliases and generated values that help you get needed values easier. You can always create variables from any of settings hash keys and work with this variable within your local scope or from other classes using fully qualified paths.:

$debug = $::fuel_settings['debug']

Some variables and structures are generated from settings hash by filtering and transformation functions. For example there is $node structure.:

$node = filter_nodes($nodes_hash, 'name', $::hostname)

It contains only settings of current node filtered from all nodes hash.

If you are going to use your module inside Fuel Library and need some settings you can just get them from this $::fuel_settings structure. Most variables related to network and OpenStack services configuration are already available there and you can use them as they are. But if your modules requires some additional or custom settings you'll have to either use Custom Attributes by editing json files before deployment, or, if you are integrating your project with Fuel Library, you should contact Fuel UI developers and ask them to add your configuration options to Fuel setting panel.

Once you have finished definition of all classes you need inside your module you can add this module's declaration either into the Fuel manifests such as cluster_simple.pp and cluster_ha.pp located inside osnailyfacter/manifests folder or to the other classes that are already being used if your additions are related to them.

Example module

Let's demonstrate how to add new module to the Fuel Library by adding a simple class that will change terminal color of Red Hat based systems. Our module will be named profile and have only one class.:

profile
profile/manifests
profile/manifests/init.pp
profile/files
profile/files/colorcmd.sh

init.pp could have a class definition like this.:

class profile {
  if $::osfamily == 'RedHat' {
    file { 'colorcmd.sh' :
      ensure   => present,
      owner    => 'root',
      group    => 'root',
      mode     => '0644',
      path     => "/etc/profile.d/colorcmd.sh",
      source   => 'puppet:///modules/profile/colorcmd.sh',
    }
  }
}

This class just downloads colorcmd.sh file and places it to the defined location if this class is run on Red Hat or CentOS system. The profile module can be added to Fuel modules by uploading its folder to /etc/puppet/modules on the Fuel Master node.

Now we need to declare this module somewhere inside Fuel manifests. Since this module should be run on every server, we can use our main site.pp manifest found inside the osnailyfacter/examples folder. On the deployed master node this file will be copied to /etc/puppet/manifests and used to deploy Fuel on all other nodes. The only thing we need to do here is to add include profile to the end of /etc/puppet/manifests/site.pp file on already deployed master node and to osnailyfacter/examples/site.pp file inside Fuel repository.

Declaring a class outside of node block will force this class to be included everywhere. If you want to include you module only on some nodes, you can add its declaration inside cluster_simple and cluster_ha classed to the blocks associated with required node's role.

You can add some additional logic to allow used to enable or disable this module from Fuel UI or at least by passing Custom Attributes to Fuel configuration.:

if $::fuel_settings['enable_profile'] {
  include 'profile'
}

This block uses the enable_profile variable to enable or disable inclusion of profile module. The variable should be passed from Nailgun and saved to /etc/astute.yaml files of managed nodes. You can do it by either downloading settings files and manually editing them before deployment or by asking Fuel UI developers to include additional options to the settings panel.