1.6. Fuse Fabric
Overview
Fuse Fabric is a technology layer that allows a group of containers to form a cluster that shares a common set of configuration information and a common set of repositories from which to access runtime artifacts. Fabric containers are managed by a Fabric Agent that installs a set of bundles that are specified in the profiles assigned to the container. The agent requests artifacts from the Fabric Ensemble. The ensemble has a list of repositories that it can access. These repositories are managed using a Maven proxy and include a repository that is local to the ensemble.
The added layer imposed on fabric containers does not change the basic deployment models, but it does impact how you specify what needs to be deployed. It also impacts how dependencies are located.
Bundle deployment
In a fabric container, you cannot directly deploy bundles to a container. A container's configuration is managed by a Fabric Agent that updates its contents and configuration based on one or more profiles. So to add a bundle to a container, you must either add the bundle to an existing profile or create a new profile containing the bundle. When the profile is applied to a container the Fuse Agent will install the bundle.
The installation process will download the bundle from a Maven repository and use the appropriate install command to load it into the container. Once the bundle is installed, the dependency resolution process proceeds as it would in a standalone container.
Things to consider
While installing bundles to a fabric container is not radically different from installing bundles in a standalone container, there are a number of things to consider when thinking about creating profiles to deploy your applications:
- Bundles must be accessible through the fabric's Maven proxyWhen a Fabric Agent installs a bundle, it must first copy the bundle to the container's host computer. To do so, the agent uses the fabric's Maven Proxy to locate the bundle in one of the accessible Maven repositories and downloads it. This mechanism ensures that all of the containers in the fabric have access to the same set of bundles.If the installed bundle is a FAB, the dependencies are also resolved using the fabric's Maven proxy. This means that all of the dependencies must be in one of the repositories the proxy is configured to access. If any dependency is not accessible through the proxy, it will not be resolved.To address this issue, you need to ensure that the fabric's Maven proxy is configured to have access to all of the repositories from which your applications will need to download bundles. For more information see chapter "Configuring a Fabric's Maven Proxy" in "Configuring and Running Red Hat JBoss Fuse".
- Fabric Agents only load the bundles specified in a profileA fabric container's contents is completely controlled by the profiles associated with it. The fabric agent managing the container inspects each of the profiles associated with the container, downloads the listed bundles, and features, and installs them. If one of the bundles in a profile depends on a bundle that is not specified in the profile, or one of the other profiles associated with the container, the bundle will not be able to resolve that dependency.To address this issue you can do one of the following:
- construct your profiles to ensure that it contains all of the required bundles and their dependencies
- deploy the application as a feature that contains all of the required bundles and their dependencies
- package the application as a FAB and allow the container to resolve the dependencies and download the required bundles
