这是一个非常普遍的错误。如果我们启用调试日志，这将有助于解决身份验证问题发生的原因。转到kafka的config目录中的log4j.properties文件，并将日志设置为debug而不是info。
如下所示，更改要调试的信息。这将有助于找出ssl连接失败的原因到底是什么。
与证书颁发或未签名的证书一样，它更容易进一步解决和调试。

log4j.rootLogger=INFO, kafkaAppender

log4j.appender.controllerAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.controllerAppender.DatePattern=.yyyy-MM-dd
log4j.appender.controllerAppender.File=/var/log/kafka/kafka-controller.log
log4j.appender.controllerAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.controllerAppender.layout.ConversionPattern=[%d] %p %m (%c)%n

log4j.appender.kafkaAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.kafkaAppender.DatePattern=.yyyy-MM-dd
log4j.appender.kafkaAppender.File=/var/log/kafka/kafka.log
log4j.appender.kafkaAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.kafkaAppender.layout.ConversionPattern=[%d] %p %m (%c)%n

log4j.appender.requestAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.requestAppender.DatePattern=.yyyy-MM-dd
log4j.appender.requestAppender.File=/var/log/kafka/kafka-request.log
log4j.appender.requestAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.requestAppender.layout.ConversionPattern=[%d] %p %m (%c)%n

log4j.appender.stateChangeAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.stateChangeAppender.DatePattern=.yyyy-MM-dd
log4j.appender.stateChangeAppender.File=/var/log/kafka/kafka-state-change.log
log4j.appender.stateChangeAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.stateChangeAppender.layout.ConversionPattern=[%d] %p %m (%c)%n

log4j.logger.kafka.controller=INFO, controllerAppender
log4j.additivity.kafka.controller=false

log4j.logger.kafka.network.RequestChannel$=WARN, requestAppender
log4j.additivity.kafka.network.RequestChannel$=false

log4j.logger.kafka.request.logger=WARN, requestAppender
log4j.additivity.kafka.request.logger=false

log4j.logger.org.IOItec.zkclient.ZkClient=INFO

log4j.logger.state.change.logger=INFO, stateChangeAppender
log4j.additivity.state.change.logger=false