Provisioning is a way that administrators can define and control applications, from development to production. The ultimate effect of the provisioning system is simplifying how applications are deployed. Administrators can control which versions of the same application are deployed to different resources, from different content sources, within the same application definition (the bundle definition). Resources can be reverted to different versions or jump ahead in deployment.
Provisioning takes one set of files (a bundle) and then pushes it to a platform or an application server (the destination). There are more complex ways of defining the content, the destinations, and the rules for that deployment, but the core of the way that provisioning handles content is to take versioned bundles and send it to the designated resource.
Provisioning works with compatible groups, not individual resources. Administrators can define groups based on disparate environments and consistently apply application changes (upgrades, new deployments, or reversions) across all group members, simultaneously.
And the type of content which can be deployed, itself, is flexible. A bundle can contain raw configuration files, scripts, ZIP archives, JAR files, or full application servers — the definition of content is fairly loose.
This is in contrast to the resource-level content management in JBoss ON. The type of content is relatively limited. Patches or configuration is applied per-resource. New applications can only be deployed as children of existing resources and it has to be another resource type.
Provisioning focuses on application management, not purely resource management.
2.1. Bundles: Content and Recipes
A bundle is a set of content, packaged in an archive. In real life, a bundle is usually an application, but it can also contain a set of configuration files, scripts, libraries, or any other content required to set up an application or a resource.
The purpose of a bundle is to take that defined set of content and allow JBoss ON to copy it onto a remote resource. The provisioning process basically builds the application on the targeted resource, so in that sense, the bundle is an application distribution. Each bundle version has its own recipe which tells JBoss ON what files exist in the bundle, any tokens which need to have real values supplied at deployment, and how to handle the bundle and existing files on the remote machine.
The recipe, configuration files, and content are all packaged together into the bundle. This is usually a ZIP file, which the agent unpacks during provisioning.
As with other content managed in JBoss ON, the bundle is versioned. Different versions can be deployed to different resources, which is good for handling different application streams in different environments (say, QA and production). Versioning bundles also allows JBoss ON to revert or upgrade bundles easily.
The bundle can contain almost any kind of content, but it has to follow a certain structure for it to be properly deployed by JBoss ON. The recipe is an Ant build file called
deploy.xml; this must always be located in the top level of the bundle archive.
Past the placement of the recipe, the files and directories within the bundle can be located anywhere in the archive. In fact, the files do not necessarily need to be included in the bundle file at all; when the bundle is created, any or all files for the bundle can be pulled off a URL, which allows the content to be taken from an SVN or GIT repository, FTP server, or website.
The bundle archive can contain other archives, such as JAR, WAR, and ZIP files. Provisioning uses Ant to build out bundles on the target machine, so any files which Ant can process can be processed as part of the bundle. The Ant provisioning system can process WAR, JAR, and ZIP archive files.