Guillaume Nodet's blog

From a high level, ZooKeeper can be seen as a replicated tree, and Fabric uses this tree to store the configuration of the various agents (we call Agent, any Karaf instance connected to the same Fabric cluster). Fabric defines a notion of profile, which is a "kind" of agent. We can define different profiles for various applications we want to deploy in Karaf, for example an ActiveMQ broker or a web server. A given agent can be assigned multiple profiles, allowing a single Karaf instance to serve multiple purposes. To configure a Karaf instance, Fabric uses the ConfigAdmin OSGi service which is the standard way to push configurations to OSGi applications. An agent will have a bundle deployed which will monitor the ZooKeeper tree and update the configurations according to the profiles it has been assigned. Each bundle will then automatically be notified of the changes through the ConfigAdmin service. It is often the case that configurations are mostly the same between sever...

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I'm very pleased to introduce FuseSource Fabric , a distributed configuration, management and provisioning system for the products supported by FuseSource : Apache ServiceMix , Apache Camel , Apache ActiveMQ and Apache CXF . The user's guide contains lots of informations, so I won't rewrite it all again, but I instead invite you to have a quick look at it. The core Fabric is deployed on top of Apache Karaf and heavily reuses the very mature Apache ZooKeeper project. I'm really excited about Fabric. I've been working on it since Apache Karaf 2.2.0 has been released and I'm glad to share this work. I won't add much more for now, but stay tuned as I plan to write a number of posts explaining the various parts of Fabric.

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While thinking about a centralized logging system for Karaf and FUSE ESB , I had this idea that instead of using a built-in JMS appender, such as the one provided by Log4j, we could instead easily use Camel for that. Camel is really the best fit for such a thing, as we'd be able to add advanced things such as redelivery, batching, compression and choose easily the transport we want (JMS or plain TCP). The OSGi EventAdmin service is also an important point for monitoring events in the OSGi runtime, as most of the OSGi services do publish events to it (Blueprint bundles events, bundle events, etc...). So this was another need for a camel component. Given Camel 2.5 will be released soon, I did not want to destabilize trunk just before the release so I've committed them to a github fork for now. Those two components are really easy to use: <blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"> <camelcontext xmlns="http://camel.apache.org/sch...

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Yesterday, the Apache Software Foundation established Karaf as a Top Level Project. It will take some time before the infrastructure resources are correctly set up, but you should see something at http://karaf.apache.org soon.

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Last week, I thought that it would be a nice idea to have JIRA notifications for our Apache projects on IRC (for projects that sometimes use an IRC channel). So I came up with a very simple solution using Camel deployed on top of Karaf . The application itself consists in a single xml file to be copied in the deploy folder of your Karaf installation. This was one of my requirements for ease of maintenance. This is possible because of the nice hot deployment mechanism for spring xml applications in Karaf. Now, if you log onto the #camel, #cxf, #servicemix or #activemq IRC channels, you'll see some messages that look like: jirabot: Claus Ibsen - Created: (CAMEL-2090) camel-jms - Option autoStartup does not work (see https://issues.apache.org/activemq/browse/CAMEL-2090 ) Those are all generated by the following applications: <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ...

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ApacheCon was really interesting this year! Recently, a lot of people have expressed a real interest in ServiceMix Kernel , our generic OSGi distribution for server side applications. We've been discussing moving this subproject into Apache Felix for several reasons: raise the visibility and awareness on ServiceMix Kernel attract a broader community Several Apache projects are planning to use ServiceMix Kernel as their container: this includes Apache James , Apache Directory and Apache ActiveMQ . The Apache Sling community is also willing to contribute to this effort along with some other groups like the OPS4J project. During this discussion, a name as been proposed by Jamie Goodyear: Apache Karaf . A carafe is a small container used for serving wine and other drinks (http://en.wikipedia.org/wiki/Carafe). In similarity to the name the Kernel allows applications to be more easily handled, and improves their characteristics (much like a bottle of wine left to breath in a dec...

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