As already mentioned earlier, Chef is used as the provisioning tool of choice to fully automate the deployment process of CoreMedia applications. Chef is a widely adopted configuration management framework, that has a steadily growing community and provides free installation instructions (cookbooks) for almost any kind of applications or infrastructures.
To learn more about the Chef configuration management tool please refer to
the official Chef
documentation at https://docs.chef.io/.
Chef Repository
The CoreMedia Blueprint workspace provides a Chef infrastructure to manage a
complex CoreMedia installation. The parts of the infrastructure are grouped as a Chef
repository, a directory layout convention required to work with
chef-server, the central management facility for complex
deployments. The chef-repo directory is located at
boxes/chef/chef-repo and consists of the following subdirectories:
cookbooks, the logical deployment unit for Chef recipes.
roles, a Chef construct to bundle recipe executions together with configuration attributes.
data_bags containing data files structured as JSON files.
environments a further topology based grouping construct of Chef.
The chef-repo directory contains README.md files
which are part of the official chef-repo template. They contain instructions how to use the
different constructs.
![[Note]](../common/images/note.png) | Note |
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For the development setup with Vagrant,
chef-solo is currently used as the provisioner, because it is
easier to start with. The chef-repo though, is prepared to use with
chef-server. To work with both environments, there are extra
recipes, that use the chef-server search capabilities to
dynamically connect nodes applications by querying nodes by their roles. These recipes have
the suffix |
Cookbooks
The chef-repo directory contains all necessary cookbooks to set up a
CoreMedia installation. This includes third-party community cookbooks from the official
Chef Supermarket site. The
cookbooks found there are being released regularly and CoreMedia strives to update the dependencies
in the workspace for every distribution release of CoreMedia
Blueprint.
In the boxes/chef/chef-repo/cookbooks directory you will find cookbooks provided
by CoreMedia:
The
blueprint-yumcookbook configures the yum package management.The
coremediacookbook handles the deployment and configuration of all CoreMedia applications.The
psdashcookbook installs and configures the PSDash processes dashboard. This cookbook is primary for development purposes, where quick insights into the log files or the basic system statistics are helpful. The dashboard can be accessed athttp://localhost:8999.
CoreMedia Cookbook
The coremedia cookbook is located at
boxes/chef/chef-repo/cookbooks/coremedia and contains the full spectrum
of Chef constructs, this includes:
recipes as the installation instructions to be executed by chef.
attributes containing the default configuration attributes for all recipes.
resources (lightweight resources LWR) to compose new recipes from. Currently there are resources for
configuration,content,probedogandworkflows. For a more detailed description view theboxes/chef/chef-repo/cookbooks/coremedia/README.mdfile written in markdown syntax, a common standard for cookbook documentation.providers (lightweight providers LWP), the implementation of the LWRs.
definitions as a macroized recipe, to reduce the repetitive declaration of Chef resources in every recipe.
libraries for concrete ruby implementation of Chef APIs.
templates to render files with parameters to disk.
The recipes of the coremedia cookbook install either logical units of deployment or configure
infrastructure or third-party services.
The recipes installing CoreMedia services are very similar, they all contain one or more
package resources installing the service and tool RPMs and a service
resource responsible for the lifecycle of the service. If present, a probedog resource watches
the availability of the service after it has been (re-)started.
In more complex recipes, the content_management_server or the
workflow_server recipe, for instance, the additional resources and
providers (LWRP) are being used to either import and publish content or upload workflows. The
reference about the configuration possibilities of those recipes can also be found in the
README.md file.
The configuration resource is responsible for configuring the CoreMedia
services and tools. It represents a Chef facade for the
configuration properties files located below /etc/coremedia on the target
machine and triggers the reconfiguration process when necessary.
By default, all Chef attributes, together with all information
gathered by Chefs inspection tool ohai are merged together into one
JSON data structure for each Chef node. By defining additional attributes either in roles or
environments, you can extend this set. The configuration resource
accesses all attributes found below the nested hash at
node['coremedia']['configuration'] and compares the ones required for an
application with the ones found currently on disk. If both sets don't match, the resource will
trigger the reconfiguration of the resource.
All keys listed in the
packages/src/main/filters/default-deployment.properties file are
available for configuration. If, for example, you may want to change the value of the JVM heap
size of the Content Management Server, you need to set your desired
value with the key configure.CMS_HEAP. In the
boxes/chef/vagrant-chef-repo/roles/management.rb, you can see, how it is done for
the vagrant deployment.
Roles
Recipes that should run together on one node are grouped together with attributes into
Chef roles. In the boxes/chef/vagrant-chef-repo/roles
directory, you find roles configured only for the Vagrant development setup.
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