Rolling problem -Dlog4j.configurationFile with two log4j2.xml files about logging-log4j2 HOT 3 CLOSED

What do you see with -Dlog4j2.debug=true set? Can you please provide those logs

from logging-log4j2.

In attach the logs retrieved after Dlog4j2.debug=true setting.
catalina.log

from logging-log4j2.

@mariusv5,

Your problem is caused by multiple log4j-api and log4j-core jars being loaded into your Tomcat system (your logs show 3 instances of ClassLoaderContextSelector, one for each web application). Each one opens a file descriptor to your log file and each one tries to rotate it. As you can imagine, this does not end well.

Log4j2 is perfectly capable of sharing the same log file between logging context, if a single copy of log4j-core is deployed in your system. Technically each logging context will then have its own copy of RollingFileAppender, but the engine that opens files and performs the rotation (RollingFileManager) will be shared.

Unlike full application servers such as Wildfly, Tomcat has not easy way to share a single library between web applications. In order to do that you need to install a set of Log4j2 artifacts in the $CATALINA_BASE/lib folder and do one of the following:

1. Remove the log4j-* artifacts from your web applications (personally I don't like the idea of modifying web applications),
2. Switch the delegation model of all web application classloaders to "parent first" (this might break some apps if they need different versions of the same library), by adding:

   <Loader delegate="true"/>
   

   to their context configuration (e.g. in $CATALINA_BASE/conf/context.xml). Cf. Tomcat documentation.
3. Use a custom classloader that looks up org.apache.logging.log4j.* classes in the parent classloader first, but uses the usual delegation for the other classes. This is basically what Tomcat does with org.apache.catalina.* and other internal classes.

You can find such a classloader in my personal repository (cf. Log4jWebappClassloader). You can find it on Maven Central under the coordinates:

<dependency>
    <groupId>eu.copernik</groupId>
    <artifactId>log4j-tomcat</artifactId>
    <version>2.18.0</version>
</dependency>

To use it, place it in the $CATALINA_BASE/lib folder together with log4j-api and log4j-core and add:

<Loader loaderClass="eu.copernik.log4j.tomcat.Log4jWebappClassLoader"/>

to your $CATALINA_BASE/conf/context.xml file.

from logging-log4j2.