[Bug]: Changeable dynamic logging not working for operator scenario

[nsettipa]

Bug Description

Strimzi changeable dynamic logging feature is required to avoid restart of Pods while changing log level during run time of the Kafka micro-services. log4.properties of kafka, cruise-control and mirror maker 2 services updated through configmap editing.

After changing the configmap, Pods getting restarted automatically. Would like your advice how to avoid Pods restart. Usually next periodic internval, new configmap changes should be enforced. That is not happening.

Steps to reproduce

1. Editing kafka Pods configmap to change the log level in log4j properties file
2. Pods getting restarted.
3. Expectation: Configuration should be enforced without Pods restart

Expected behavior

No response

Strimzi version

0.36

Kubernetes version

1.25

Installation method

No response

Infrastructure

No response

Configuration files and logs

No response

Additional context

No response

[ppatierno]

This is not a bug but the expected behavior. The Kafka version within 0.36.0 is using log4j1 which doesn't have any dynamic reloading. You change the ConfigMap, it's reflected in the volume at some point in time but the pod needs a restart to get the new configuration anyway. With the coming 0.46.0 version, Kafka 4.0 will use log4j2 and leveraging the dynamic reloading there.

[scholzj]

It is not as simple as that. Some Log4j1 things can be changed dynamically and are changed dynamically in Strimzi 0.36. But not everything can be changed that way - e.g. layouts, new loggers etc. will need restart. So hard to say without any details if it is fully expected or not.

[ppatierno]

Some Log4j1 things can be changed dynamically and are changed dynamically in Strimzi 0.36

which ones?

[scholzj]

@sknot-rh might still know the details. But definitely at least the log levels for existing loggers in Kafka, Connect and MM2 are changed dynamically. If you check my Kafka 4.0.0 PR you will see that I had to disable this in the KafkaRoller and in the Connect / MM2 assembly operators.

[nsettipa]

Hi, Thanks for quick response. This is with regard to enabling Kafka broker logs dynamically by editing configmap. As per below strimzi documentation, it is possible to change, but Pod restart happening. Need some advice on this. https://strimzi.io/blog/2020/11/10/dynamically-changeable-logging/ I was trying below steps as per the documentation, but still Pod restart happening: ------------------------------------------------------------------------------------------------------------ Automatic reloading works in these steps: 1. Logging configuration is changed in the custom resource 2. During reconciliation, the log4j2.properties file containing the configuration from the custom resource is remounted. 3. log4j2 polls changes in the log4j2.properties file in an interval of monitorInterval seconds Appreciate suggestions. Thanks in advance. Rgds, Narasimham

…

On Mon, 10 Mar 2025 at 22:02, Jakub Scholz ***@***.***> wrote: It is not as simple as that. Some Log4j1 things can be changed dynamically and are changed dynamically in Strimzi 0.36. But not everything can be changed that way - e.g. layouts, new loggers etc. will need restart. So hard to say without any details if it is fully expected or not. — Reply to this email directly, view it on GitHub <#11244 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AC7EJS72CSF2VPRFWLZIP2D2TW5B3AVCNFSM6AAAAABYWTGNM2VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTENBVGE3TIMI> . You are receiving this because you authored the thread.Message ID: <strimzi/strimzi-kafka-operator/repo-discussions/11244/comments/12451741@ github.com>

[ppatierno]

But you are referring to log4j2 which, in the version of Strimzi you are using, was supported only for some components and not the Kafka brokers, MM and CC (see the article in details).
As Jakub said, maybe we log4j1 you can change "something" like the log levels but the rest needs restarts.

[scholzj]

Yeah, so ... as Paolo said, you should still use Log4j1. Maybe that is part of the problem? Hard to say when you are not sharing any details.

[nsettipa]

In which version of Strimzi, it is supported for Kafka Pods. So that we plan uplift of strimzi version.

…

On Tue, 11 Mar 2025 at 14:08, Paolo Patierno ***@***.***> wrote: But you are referring to log4j2 which, in the version of Strimzi you are using, was supported only for some components and not the Kafka brokers, MM and CC (see the article in details). As Jakub said, maybe we log4j1 you can change "something" like the log levels but the rest needs restarts. — Reply to this email directly, view it on GitHub <#11244 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AC7EJS6PWDCD2GPQEITRTQ32T2OIVAVCNFSM6AAAAABYWTGNM2VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTENBVHA4TQNQ> . You are receiving this because you authored the thread.Message ID: <strimzi/strimzi-kafka-operator/repo-discussions/11244/comments/12458986@ github.com>

[ppatierno]

The support for log4j2 is coming with Kafka 4.0 (which is not released yet) and so with the next Strimzi 0.46.0. But there is not a well defined ETA for that.