logging

Ready-to-use virtual clusters

vCluster is a solution for creating virtual clusters within a host Kubernetes cluster. Virtual clusters are a Kubernetes concept that enables isolated clusters to be run within a single physical Kubernetes cluster. Each cluster has its own API server, which makes them better isolated than namespaces and more affordable than separate Kubernetes clusters. — What are virtual clusters?

Technical

Send your logs to Loki

One of my current talks focuses on Observability in general and Distributed Tracing in particular, with an OpenTelemetry implementation. In the demo, I show how you can see the traces of a simple distributed system consisting of: the Apache APISIX API Gateway, a Kotlin app with Spring Boot, a Python app with Flask, and a Rust app with Axum. Earlier this year, I spoke and attended the Observability room at FOSDEM.

Java

System Logger

December was not a good time for Java developers and even less for Ops. The former had to repackage their apps with a fixed Log4J’s version, and the latter had to redeploy them - several times. Yet, every cloud has a silver lining. In my case, I learned about System.Logger. There was a 'Moved Permanently' error fetching URL: 'https://twitter.com/OndroMih/status/1469599938782932992' In short, System.Logger is a façade over your logging engine.

Java

Feedback on the Log4J2 hack in Spring Boot

Last week, I wrote a post that described how to hack the Maven dependency resolution system. I admit it was a dirty hack, it’s even in the post name. But I got it wrong. Thanks Stéphane Nicoll for pointing it out: There was a 'Moved Permanently' error fetching URL: 'https://twitter.com/snicoll/status/1338394993162145792' Even though I linked the documentation, I misread it. Here’s my mea culpa.

Java

A dirty hack to ease the usage of Log4J2 in Spring Boot

Logging is one of the fundamental components of any application which runs in production. Yet, between performance and logging in critical environments, I’d favor the former. For that reason, modern logging frameworks should implement at least two requirements: Async appenders: the write operation shouldn’t be blocking the execution of the programLazy computation: the framework doesn’t run expensive computations until they are needed - or never if that’s the case.

Java

Logging additional metadata

In February, before the lockdown, I presented my Fast logs talk at ConFoo. At the end, I had an interesting question I had to cut short because of the timing. This blog post aims to describe the relevant points of the talk, the question, as well as some possible answer. One improvement to have faster logs In this talk, I highlight different ways to make logs faster. Nowadays, most logs are aggregated into a single place for later usage.

Development

Smart logging in Java 8 and Kotlin

Logging is a not a sexy subject but it’s important nonetheless. In the Java world, logging frameworks range from Log4J to SLF4J via Commons Logging and JDK logging (let’s exclude Log4J 2 for the time being). Though different in architecture and features, all of their API look the same. The logger has a method for each log level e.g.: debug(String message)info(String message)error(String message)etc. Levels are organized into a hierarchy.

Java

Log management in Spring Boot

Logging is for sure not a glamorous subject, but it’s a critical one - at least for DevOps and Ops teams. While there are plenty of material on the Web describing how to change your ASCII banner, there is not much on how to efficiently manage the log output. By default, Spring Boot will output log on the console and not use any file at all. However, it’s possible to tell Spring Boot to log in an output file. At the simplest level, the path where Spring Boot will put the spring.

Java

Configuring Maven to use SLF4J

I mainly write articles for two reasons: to understand something that is new to me or to document something I regularly have to explain to others. This article definitely falls in the second category: in order to celebrate the new 1.0.0 version of Logback, I’ve decided to write down once and for all how to properly use SLF4J with Maven since it seems there’s no shortage of questions about it.

Java

Thoughts on Java logging and SLF4J

In this post, I will ramble on logging in Java, how it was done in the old days and what can a library like SLF4J can bring.

Java

JMX use cases

JMX is a Java standard shipped with the JDK since Java 5. Though it enables you to efficiently and dynamically manage your applications, JMX has seen very few activity. In this article, I will show you the benefits of using such a technology in a couple of use cases.