Skip to main content

Posts

Showing posts from August, 2025

Migration to log4j2 in Apache Kafka 3.9.1

Greetings, TLDR: are there any known problems with replacing reload4j with log4j2 directly on the CLASSPATH for Apache Kafka 3.9.1? Our application runs Apache Kafka 3.9.1 and there is a thought to replace the jar of reload4j with the jar of log4j2 on the CLASSPATH when starting the Apache Kafka cluster, could anyone, please share their experience on the matter and what problems such a replacement might lead to? I perused the source code of Apache Kafka 3.9.1 and I found many `import`s of `org.apache.log4j.*` in Kafka Connect, does it mean that Mirror Maker 2's logger can malfunction? Main main concern with log4j2 is that such a migration only happened in Apache Kafka 4.0 almost 10 years after log4j1.2 was declared End of Life (August 2015). Does anyone remember if there have been any obstacles to migrate to log4j2 earlier? I know of the Log4Shell (CVE-2021-44228) vulnerability in log4j2, but it was only reported in 2021, almost 6 years after log4j1.2 was decla...