Tomcat logs are being written to syslog instead to the application log in Spring Boot and Log4j - spring

Question

It's a Spring Boot application with Log4j for logging.
All logs from org.apache.catalina.* are being sent to syslog, and it includes also uncaught exceptions.
Our app uses Log4j (v1) since it uses legacy code dependencies that use Log4j.
Spring Boot version is 1.5.2.RELEASE.
I believe that with correct set-up, also tomcat logs will be written to the same file that is configured in the log4j.xml, but i couldn't find any answer to that problem.
pom.xml (relevant parts):
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>${spring.boot.version}</version>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- Spring Logging -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j</artifactId>
<version>1.2.8.RELEASE</version>
</dependency>
log4j.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration debug="true"
xmlns:log4j='http://jakarta.apache.org/log4j/'>
<appender name="consoleAppender" class="org.apache.log4j.ConsoleAppender">
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d{ISO8601} [%t] %5p %c{1} - %m%n" />
</layout>
</appender>
<!-- File appender -->
<appender name="logFileAppender" class="org.apache.log4j.FileAppender">
<param name="File" value="/tmp/myappname.log"/>
<param name="Append" value="true" />
<param name="BufferedIO" value="false" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d{ISO8601} [%t] %5p %c{1} - %m%n" />
</layout>
</appender>
<root>
<level value="INFO"/>
<appender-ref ref="consoleAppender" />
<appender-ref ref="logFileAppender" />
</root>
</log4j:configuration>

Answer 1

Could you try excluding it in the actuator artifact?
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
Based on your comment:
If I understood correctly, the application is logging fine, it's the servlet container the logging to syslog when exceptions bubble up, isn't?
Could you also try adding:
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-logging-log4j</artifactId>
</dependency>
and / or passing where log4j config file is located:
-Dlog4j.configuration=<path to file>
If these don't work, the only thing I could think of is that you are using Spring Boot 1.5.x doesn't get along with Log4j and likely requires to uplift it to Log4j2