You can create some high value resources using CloudFormation that you’d like to ensure exist even after a stack has been removed. Imagine being the admin to accidently delete the wrong stack and having to watch as your RDS master, and all your prod data, slowly vanishes in to the void of AWS reclaimed volumes. Luckily AWS provides a way to reduce this risk, the DeletionPolicy Attribute. By specifying this on a resource you can ensure that if your stack is deleted then certain resources survive and function as usual. Read on →

While AWS CloudFormation is one of the best ways to ensure your AWS environments are reproducible it can also be a bit of an awkward beast to use. Here are a couple of simple time saving tips for refining your CFN template parameters. The first one is also the simplest, always define at the least a MinLength property on your parameters and ideally an AllowedValues or AllowedPattern. This ensures that your stack will fail early if no value is provided. Read on →

Have you ever needed to access Ansible facts from inside Puppet? well, if you ever need to, you can use the basic ansible_facts custom fact. # make sure you have ansible installed $ sudo puppet resource package ansible ensure=present # clone my experimental puppet fact repo $ git clone # Try running the fact $ ruby -I unixdaemon-puppet_facts/lib/ `which facter` ansible_facts -j { "ansible_facts": { "ansible_architecture": "x86_64", "ansible_bios_date": "04/25/2013", "ansible_bios_version": "RKPPT%$DSFH.86A.0457.20DF3.0425.1251", "ansible_cmdline": { ... Read on →

Puppet’s always had a couple of little inconsistencies when it comes to the file and template functions. The file function has always been able to search for multiple files and return the contents of the first file found but it required absolute paths. The template function accepts module based paths but doesn’t allow for matching on the first found file. Although this can be fixed with the Puppet Multiple Template Source Function. Read on →

In the past if you wanted to run your own puppet-lint checks there was no official, really clean way to distribute them outside of the core code. Now, with the 1.0 release of puppet-lint you can write your own, external, puppet-lint checks and make them easily distributable. I spent a little bit of time this morning reading through the existing 3rd party community plugins and after porting a private absolute template path check over to the new system I have to say that rodjek has done an excellent job with both the ease of writing your own checks and the quality of the developer tutorial. Read on →

A little while ago in a twitter conversation, many hops away a few of us discussed the Puppet Certified Professional exam and topic coverage. Specifically how much of it was focused on Puppet Enterprise (PE) and if it would either dissuade users of purely FOSS Puppet or heavily impact their chance of passing if they’d never used PE. While I stand by my views I began to worry that my knowledge of the syllabus was only based on hearsay, the practice exam questions and that I was being overly harsh and possibly spreading misinformation through my own ignorance. Read on →

It is amazing how many small commitments and fragments of an online presence you can collect over years of being involved in different projects and user groups. I’ve ended up hosting planets, user group sites, submission forms (and other scripts), managing twitter announcement accounts, pushing tar balls (don’t ask) and running (and owning) more domains than I could ever really want or do anything useful with. After an initial audit of how difficult it’d be to move some of my public servers I’ve realised that something has to change. Read on →

Once we started linking multiple CloudFormation stacks together with Ansible we started to feel the need to query Amazon Web Services for both the output values from existing CloudFormation stacks and certain other values, such as security group IDs and Elasticache Replication Group Endpoints. We found that the quickest and easiest way to gather this information was with a handful of Ansible Lookup Plugins. I’ve put the code for the more generic Ansible AWS Lookup Plugins on github and even if you’re an Ansible user who’s not using AWS they are worth a look just to see how easy it is to write one. Read on →

Constructing a large, multiple application, virtual datacenter with CloudFormation can quickly lead to a sprawl of different stacks. The desire to split things sensibly, delegate control of separate tiers and loosely couple as many components as possible can lead to a large number of stacks, lots of which need values from stacks created earlier in the run order. While it’s possible to do this with the native AWS CloudFormation command line tools, or even some clever bash (or Cumulus), having a strong, higher level tool can make life a lot easier and reproducible. Read on →

I’ve been doing my usual quarterly sweep of the always too full bookshelves and hit the usual dilemma of what to keep, what to donate to charity and what to recycle. Among the technical books in this batch is the ‘Sendmail Cookbook’, something I’ve always kept as a good luck charm to ward off the evil of needing to work with mail servers with m4 based configuration languages. Sendmail is one of those projects that I’ve not kept up with over the years. Read on →