Use nodes with defined resource in nginx configuration

[Frederik Bjerggaard Nielsen]

Hi,

I am working on making our puppet infrastructure more dynamic where I can add any number of nodes and these will automatically be applied in another nodes configuration.

An example:

I have X number of hosts running a Java application, which are defined by our javaapp module with the following define in it (simplified):

define javaapp::site (
  $site_name,
  $site_port ) {
  # Doing some stuff regarding deployment etc here
}

These are defined in the site.pp file like this:

javaapp::site { 'app01':
  play_site_name    => 'app01',
  play_site_port    => 9100,
}

We have a nginx reverse proxy in front of these application servers where I need to forward requests to a range of servers. Currently my nginx template looks like this:

upstream app-hosts {

  server <%= @host_app_01 %>:9100;

  server <%= @host_app_02 %>:9100;

}

Where @host_app_01 and @host_app_02 have been defined globally in the site.pp file with the IP of the nodes.

What I would like to do is to collect an array of the nodes with a specific javaapp site name and use it in the nginx template.

I have read a little about exported resources, but I can't figure out whether it is the right thing for this situation?

Is it even possible to do with puppet?

We are running puppet version 3.7.5.

Thanks in advance.

Regards

Frederik Nielsen

[Lowe Schmidt]

Exported resources would accomplish what you are trying to do, as long as you don't often and rapidly remove and add upstream app-hosts. 

--

Lowe Schmidt | +46 723 867 157

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[Gareth Rushgrove]

On 19 January 2016 at 11:34, Lowe Schmidt <m...@loweschmidt.se> wrote:
> Exported resources would accomplish what you are trying to do, as long as
> you don't often and rapidly remove and add upstream app-hosts.
>

If you find you do want to change things more rapidly, integrating
with a service discovery mechanism is a nice approach.

This repo, and accompanying presentation I gave last year demonstrate
using Consul, along with the Consul module and Hiera backend to
accomplish dynamic changes to configuration of an nginx upstream. The
demo uses Puppet Enterprise but the approach is general purpose, and
the modules are all open source and from the wider Puppet community.

https://github.com/puppetlabs/puppet-enterprise-consul-docker-demo
https://speakerdeck.com/garethr/service-discovery-and-configuration-management

The key trick is to use some sort of watcher (in my case the build-in
consul watcher setup using the ::consul::watch Puppet type) to detect
changes across the cluster as they happen and to run Puppet to update
the proxy straight away.

Gareth

> https://groups.google.com/d/msgid/puppet-users/CAC-wWcQTTqcZe1x3rfswQmTyV1pzMKNcMSFe5RHNZtCB43Q8pw%40mail.gmail.com.

>
> For more options, visit https://groups.google.com/d/optout.

--
Gareth Rushgrove
@garethr

devopsweekly.com
morethanseven.net
garethrushgrove.com

[Justin Rowles]

Hi Gareth,

I'd be interested on your feedback with a gem that we at BGCH have just released: bgch-hiera-consul.  It's on rubygems.

It's derived from lynxman's hiera-consul, but the behaviour is different.  It permits storing yaml and/or json as a value and parses it for hiera variables.

Hope you like it!

Justin.