<logger name="kafka.network.RequestChannel$" additivity="false" level="WARN">
    <appender-ref ref="requestAppender"/>
  </logger>

16:07:38,628 |-ERROR in ch.qos.logback.core.joran.spi.Interpreter@701:80 - RuntimeException in Action for tag [logger] java.lang.IllegalArgumentException: Failed to parse input [kafka.network.RequestChannel$]
    at java.lang.IllegalArgumentException: Failed to parse input [kafka.network.RequestChannel$]
    at     at ch.qos.logback.core.util.OptionHelper.substVars(OptionHelper.java:114)
    at     at ch.qos.logback.core.joran.spi.InterpretationContext.subst(InterpretationContext.java:157)
    at     at ch.qos.logback.classic.joran.action.LoggerAction.begin(LoggerAction.java:44)
    at     at ch.qos.logback.core.joran.spi.Interpreter.callBeginAction(Interpreter.java:269)
    at     at ch.qos.logback.core.joran.spi.Interpreter.startElement(Interpreter.java:145)
    at     at ch.qos.logback.core.joran.spi.Interpreter.startElement(Interpreter.java:128)
    at     at ch.qos.logback.core.joran.spi.EventPlayer.play(EventPlayer.java:50)
    at     at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:148)
    at     at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:135)
    at     at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:100)
    at     at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:50)
    at     at ch.qos.logback.classic.util.ContextInitializer.configureByResource(ContextInitializer.java:75)
    at     at ch.qos.logback.classic.util.ContextInitializer.autoConfig(ContextInitializer.java:150)
    at     at org.slf4j.impl.StaticLoggerBinder.init(StaticLoggerBinder.java:84)
    at     at org.slf4j.impl.StaticLoggerBinder.<clinit>(StaticLoggerBinder.java:55)
    at     at org.slf4j.LoggerFactory.bind(LoggerFactory.java:147)
    at     at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:122)
    at     at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:378)
    at     at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:328)
    at     at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:349)
    at     at org.apache.kafka.common.utils.Utils.<clinit>(Utils.java:54)
    at     at kafka.Kafka$.getPropsFromArgs(Kafka.scala:41)
    at     at kafka.Kafka$.main(Kafka.scala:57)
    at     at kafka.Kafka.main(Kafka.scala)
Caused by: ch.qos.logback.core.spi.ScanException: Unexpected end of pattern string
    at     at ch.qos.logback.core.subst.Tokenizer.tokenize(Tokenizer.java:70)
    at     at ch.qos.logback.core.subst.NodeToStringTransformer.tokenizeAndParseString(NodeToStringTransformer.java:53)
    at     at ch.qos.logback.core.subst.NodeToStringTransformer.substituteVariable(NodeToStringTransformer.java:46)
    at     at ch.qos.logback.core.util.OptionHelper.substVars(OptionHelper.java:112)
    at     ... 23 common frames omitted