2.3. Update a Profile

Normally, when you edit a profile that is already deployed in a container, the modification takes effect immediately. This is because the Fabric Agent in the affected container (or containers) actively monitors the fabric registry in real time.

In practice, however, immediate propagation of profile modifications is often undesirable. In a production system, you typically want to roll out changes incrementally: for example, initially trying out the change on just one container to check for problems, before you make changes globally to all containers. Moreover, sometimes several edits must be made together to reconfigure an application in a consistent way.

For quality assurance and consistency, it is typically best to modify profiles atomically, where several modifications are applied simultaneously. To support atomic updates, fabric implements profile versioning. Initially, the container points at version 1.0 of a profile. When you create a new profile version (for example, version 1.1), the changes are invisible to the container until you upgrade it. After you are finished editing the new profile, you can apply all of the modifications simultaneously by upgrading the container to use the new version 1.1 of the profile.

For example, to modify the default profile, when it is deployed and running in a container, follow the recommended procedure:

You can easily roll back to the old version of the default profile, using the fabric:container-rollback command like this:

JBossFuse:karaf@root> fabric:container-rollback 1.0 child