Let’s build a Raspberry Pi Cluster running Docker and Kubernetes. There has been already a handful of good recipes, however this howto is a bit different and provides some unique features.
rhuss/docker-maven-plugin is dead, long live fabric8io/docker-maven-plugin !
Dealing with multiple Docker registries is hard, mostly because the meta information where a image is located is part of a Docker image’s name, which is typically used as an identifier, too.
Let’s see how the rhuss/docker-maven-plugin deals with this peculiarity.
This screencast gives a live demo of the forthcoming JMX notification support in Jolokia 2.0.
I hope you all had a good start into 2016 and have charged all your batteries during the time of stillness.
Jolokia had a good start, too. During the holiday season I took the opportunity to continue to work on version 2.0 which now takes on form. If you have followed the history of Jolokia you know that work on 2.0 started early 2013 but advanced quite slowly for multiple reasons.
Now its time to go out on a limb with announcing Jolokia 2.0 for 2016. A bit of pressure sometimes really helps ;-)
When I had to create multiple Docker base images which only differ slightly for some minor variations I couldn’t avoid to feel quite dirty because of all the copying & pasting of Dockerfile fragments. We all know how this smells, but unfortunately Docker has only an answer for inheritance but not for composition of Docker images. Luckily there is now fish-pepper, a multi-dimensional docker build generator, which steps into the breach.
As you might know, Jmx4Perl is the mother of Jolokia. But what might be not so known is, that Jmx4Perl provides a set of nice CLI tools for accessing Jolokia agents. However, installing Jmx4Perl manually is cumbersome because of its many Perl and also native dependencies.
However, if you are a Docker user there is now a super easy way to benefit from this gems.
Ok, you know Docker. And since you are a Java developer you want to know how you can use this in your daily development workflow. You probably also heard about the docker-maven-plugin which seamlessly creates Docker images, starts and stops Docker containers and more all with a concise configuration syntax.
And now there is this new goal
Building a Docker wormhole is easy.
The HTTP-JMX Bridge Jolokia allows easy access to JMX. It exposes all JMX information and operations via an REST-like interface and has tons of nifty features. Jmx4Perl on the other side is a client for Jolokia, which beside Perl access modules also provides quite some nice CLI tools for accessing and installing Jolokia. This post explains how install these tools on OS X.
A health check is a useful technique for determining the overall operational state of a system in a consolidated form. It provides some kind of internal monitoring which collects metrics, evaluates them against some thresholds and provides a unified result. Health checks are now coming to Jolokia. This post explains the strategy to include health checks into Jolokia without blowing up the agents to much.
A local Maven repository serves as a cache for artifacts and dependencies, we all know this. This helps in speeding up things but can cause subtle problems when doing releases. Docker can help here a bit for avoiding caching issues.
My docker-maven-plugin is undergoing a major refactoring. This post explains the motivation behind this and also what you can expect in the very near future. The configuration syntax becomes much cleaner and implicit behavior was removed.
While on the way of transforming the Jolokia integration test suite from a tedious, manual, half-a-day procedure to a full automated process I ran into and felt in love with Docker. As a byproduct a java-jolokia docker repository emerged, which can be easily used as a Java base image for enabling a Jolokia JVM agent during startup for any Java application.
Recently I gave a Meetup talk for the Docker Munich Meetup Group which explained how Docker can help developers to improve integration tests and to ship applications.
Jolokia has configurable CORS support so that it plays nicely together with the Browser world when it comes to cross origin requests. However, Jolokia’s CORS support is not without gotchas. This post explains how Jolokias CORS supports works, what are the issues and how I plan to solve them.