.. which is in fact a cookbook :-)

Due to the need of applying different roles/customizations to some groups of hosts, based on different influence factors (like the data center where the node is running or if it is a physical or a virtualized host).

After we were bored to manually update the role for the data center in which a VM is running after a server move or the stupidity to declare a debian role during node bootstrap, we decided to refactor our base cookbook and e.g. make use of information coming from Ohai through automatic attributes (like node[:platform] = "debian").

While such details like operating system specific things are not handled in this cookbook yet, this is the starting point for all the magic and also home of couple of libraries, which are explained below

This part automatically includes the operatingsystem cookbook.

If the node is running on bare metal, the base::physical recipe is automatically included. If not (thus running virtualized), then base::virtualized allows customizations only for virtual machines.

If any virtualization technique is in use, the cookbook for this technique is automatically (gracefully) loaded (node[:virtualization][:system] is vbox, openvz, vmware, ...). If the a #{node[:virtualization]][:system]}::default recipe is not available, no error is thrown.

It is then the job of that cookbook to differ between custmomizations for host/guest.

In case we are not running on chef-solo, whe include our datacenter cookbook, which then on the one hand deploys essentials for running in production (like including monitoring) and on the other hand can apply DC-specific customizations (like NTP or mail-relay servers), based on the information, in what DC it is running.

Typo3::Base::Recipe

In order to include specialized recipes only if they exist (but not to fail when they not exist) we created the include_if_available functionality.

For example, we would not fail a chef run, if this base role (and the included operatingsystem cookbook) would run on a CentOS node, when wo do not need any customizations for that and thus have no dedicated recipe.

Instead of

include_recipe "operatingsystem::#{node[:platform]}"

which would fail when somebody tries a new platform, the library enables us to savely do this

include_if_available "operatingsystem::#{node[:platform]}"

Typo3::Base::Node

This library gives information about the machine, where Chef is running.

• physical? - true, if the node is running on bare metal
• virtualized? - true, if Ohai detected that this node is running within a virtualized environment
• virtualization? - true, if virtualization is in use and this node is either host or guest.