Automated configuration management tools and strategies.
When doing software testing, your testing tool is normally separate from the language and libraries you’re building the software with (but almost always written in the same language). When testing your infrastructure, I think it makes perfect sense to apply this practice.
More from Agile Testing’s Grig Gheorghiu on setting up Opscode Chef, creating your own cookbook, modifying an existing cookbook, creating a role and adding a client machine to that role.
Can you remember the last time when you had to apply patches or config file changes to a system. And did you have that fingers crossed feeling? Wouldn’t it be great that you could install a patch and run a series of tests to see if everything behaved the way it should?
Cloud computing says that building servers is undifferentiated heavy lifting; unless your service is building servers, you should really let someone else do it and focus on the product or service you’re actually trying to sell. Configuration Management is the first step in bringing this same ideology to configuring systems.
Agile Testing’s Grig Gheorghiu provides a simple, step-by-step tutorial for installing Opscode Chef and getting a Chef client to talk to a Chef server.
Vagrant is a tool for building and distributing virtualized development environments, providing easy to configure, lightweight, reproducible, and portable virtual machines targeted at development environments. Vagrant includes automated virtual machine creation using Oracle’s VirtualBox, automated provisioning of virtual environments using Opscode Chef, port forwarding to the host machine, full SSH access to created environments, shared folders, packaging environments into distributable boxes, and easy teardown and rebuild of your environments.
Hosts in a well-architected enterprise infrastructure are self-administered; they perform their own maintenance and upgrades. By definition, self-administered hosts execute self-modifying code. They do not behave according to simple state machine rules, but can incorporate complex feedback loops and evolutionary recursion.
Resources to help you learn about Puppet or master more advanced technical issues.
Masterzen explains how to offload the job of Puppet static file serving onto Nginx, a small and performant web server, and also how to have Nginx cache the files. He also gives a recipe for configuring Nginx to cache the compiled catalogs for each machine, reducing some of the compute load on the Puppet server.
think it makes sense to use a tool like Puppet for the initial configuration of the OS and of the packages required by your application. When it comes time to deploy your application, I think a tool like Fabric is more appropriate.
So far, my biggest problem with Nagios has been finding the time to add new systems to it, figuring out what services to check, etc. It’s not a particularly difficult thing to do, but in the grand scheme of things, it was just something that always fell by the wayside in the drive to get more systems set up, deal with user problems, and put out the inevitable fires. That is, until recently.
How to set up continuous integration testing for Puppet manifests.
Excellent introduction to Puppet for cloud management by Jeff Wallace, featuring EC2 and Rackspace Cloud integration, Puppet classes, using Ruby logic in ERB templates, and inheriting node definitions to create identical configurations.
cucumber-puppet is the glue between cucumber and Puppet, allowing you to write behavioural tests, or features as cucumber calls it, for your Puppet manifest.
It’s been said that deploying Java apps is hard for Linux packages, but Puppet makes it very easy. This is only the tip of the iceberg—you can use the same tool to deploy mailservers and databases as well as appservers. It fits in well whether you have 20 machines or thousands. It’s agnostic to cloud vs physical hardware, and plays nicely in all places. The example that follows below is designed to be executed locally, though in a typical deployment, you’ll host it on a central server, called a puppetmaster, and then roll your configuration out to the nodes using puppet.
People complain that Puppet is non-deterministic. On a certain level that is like complaining that threads are non-deterministic. That’s the way the model works by design. If there is logic that depends on the order of execution, that code needs mutex/syncronization. Threads create issues, but they also solve some.
Great article on configuring the Puppet server to use Passenger and Apache, with a complete example vhost definition for puppetmasterd.
Setting up a staging environment for your modules, manifests and files on the puppetmaster. Test your modules, manifests, templates files and facts before deploying on production servers.
Other tools and frameworks for configuration management.
Kokki is a configuration management framework inspired by Chef.
Moonshine is an opensource configuration management and deployment system that follows the Rails way, simplifying server configuration, dependency management, and Rails application deployment, using Ruby and Puppet.
slaughter is a simple tool which will allow policies to be downloaded, via HTTP, from a central server and executed upon a local machine. The intention is that these local policies may be written in a portable fashion and used to automate the administration of a large number of Linux machines.
Sprinkle is based on capistrano and uses the same push model without any additional infrastructure.
