Showing posts from March, 2020

Apache Karaf Decanter 2.3.0, new Prometheus appender

As said in my previous post, Apache Karaf Decanter 2.3.0 is a major new release bringing fixes, improvements and new features. We saw the new alerting service. In this blog post, we see another new feature: the Prometheus Appender. Prometheus ? Prometheus ( ) is a popular metrics toolkit, especially for cloud ecosystem. It’s open-source and it’s part of the Cloud Native Computing Foundation. If Karaf Decanter provides similar collecting and alerting features, it makes sense to use Decanter as collector that Prometheus can request. Then, the visualization and search can be performed on Prometheus. Decanter Prometheus Appender The preferred approach with Prometheus is to “expose” a HTTP endpoint providing metrics that the Prometheus platform can retrieve. It’s what the Decanter Prometheus Appender is doing: bind a Prometheus servlet that Prometheus can “poll” get the incoming data from the Decanter Collectors detects the numbers in the event data creates Prometheus

Apache Karaf Decanter 2.3.0, the new alerting service

Apache Karaf Decanter 2.3.0 will be released soon. This release brings lot of fixes, improvements and new features. In this blog post, we will focus on one major refactoring done in this version: the alerting service. Goodbye checker, welcome alerting service Before Karaf Decanter 2.3.0, the alert rules where defined in a configuration file named etc/org.apache.karaf.decanter.alerting.checker.cfg . The configuration were simple and looked like. For instance: message.warn=match:.*foobar.* But the checker has three limitations: it’s not possible to define a check on several attributes at same time. For instance, it’s not possible to have a rule with something like if message == 'foo' and other == 'bar' . it’s not possible to have “time scoped” rule. For instance, I want to have an alert only if a counter is great than a value for x minutes. A bit related to previous point, the recoverable alerts are not perfect in the checker. It should be a configuration of the alert rul