agent needs to get info from another agent (dependency)

[Sai Kothapalle]

Hi,

 Here is my unique case. I have a speech search application for which the standard installation is to install the application components on 3 nodes or agents. The components have the following depency

•  Agent 1 needs hostname of agent 2 and agent 3 which is written into a config file
  
•  Agent 2 and Agent 3 need the private IP address of Agent 1 to be written into a config file which it uses while starting up the service.
  

I am able to install the packages using puppet and load the config files using erb templates. However, I am unsure of how to go about the dependency between agents. Did lookup Exported resources but while the syntax gives an option to export a type, how do I export IP address etc. is there a better option> Thanks for the help

[Felix Frank]

Hi,

yes, you will need exported resources, and it won't be an easy design at all.

I imagine it would work roughly like this (assuming Agent 1 runs central_server and Agents 2 and 3 run slave_server instances).

Sketch of the manifest for the central server:

class central_server {
    concat { '/etc/server_config': ... }
    Central_server_snippet<<| tag == 'this-cluster' |>>
}

define central_server_snippet($slave_name) {
    concat::fragment { "central-server-$name":
      target => '/etc/server_config',
      content => "something-with $slave_name\n";
    }
    @@slave_server_snippet { "for-$name": content => "something-with $ipaddress" }
}

The slave servers do:

class slave_server {
    @@central_server_snippet { "$fqdn": slave_name => "$hostname" }
    Slave_server_snippet<<| title == "for-$fqdn" |>>
}

The idea being that the central server will not export its settings to the slaves before they have exported their respective names to him.

Untested and incomplete. YMMV.

Cheers,
Felix