Flink on Yarn 模式下，业务应用内部配置的 logback.xml/log4j.properties 是无法加载的，Flink 会默认采用安装目录下的 $FLINK_HOME/logback.xml/log4j.properties 作为统一的 logger 定义文件。
Flink 提供的 logback.xml/log4j.properties 只配置了 rootLogger，如果不加修改，集群上面运行的所有作业日志都将输出到 rootLogger 指向的目录。随着时间的增长日志量会很大，加载会非常慢甚至直接导致页面挂掉。
因此可以通过修改 $FLINK_HOME/conf/logback.xml 文件的方式对日志进行定制(官方推荐使用logback.xml)。
一、实现步骤：
1、修改 $FLINK_HOME/conf/logback.xml
指定 Appender 为 RollingFileAppender，配置你想要的滚动策略（这里只做示例，具体配置根据需求定制）。
<!--
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~ or more contributor license agreements. See the NOTICE file
~ distributed with this work for additional information
~ regarding copyright ownership. The ASF licenses this file
~ to you under the Apache License, Version 2.0 (the
~ "License"); you may not use this file except in compliance
~ with the License. You may obtain a copy of the License at
~
~ http://www.apache.org/licenses/LICENSE-2.0
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-->
<configuration>
<!-- 按照每日滚动的方式生成日志文件 -->
<appender name="file" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${log.file}</file>
<append>false</append>
<rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
<!-- 日志按天滚动 -->
<fileNamePattern>${log.file}_%d{yyyy-MM-dd}.%i</fileNamePattern>
<!-- 每个文件最大50MB, 保留7天的历史日志, 最多保留2GB -->
<maxFileSize>50MB</maxFileSize>
<maxHistory>7</maxHistory>
<totalSizeCap>2GB</totalSizeCap>
</rollingPolicy>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{60} %X{sourceThread} - %msg%n</pattern>
</encoder>
</appender>
<!-- This affects logging for both user code and Flink -->
<root level="INFO">
<appender-ref ref="file"/>
</root>
<!-- Uncomment this if you want to only change Flink's logging -->
<!--<logger name="org.apache.flink" level="INFO">-->
<!--<appender-ref ref="file"/>-->
<!--</logger>-->
<!-- The following lines keep the log level of common libraries/connectors on
log level INFO. The root logger does not override this. You have to manually
change the log levels here. -->
<logger name="akka" level="INFO">
<appender-ref ref="file"/>
</logger>
<logger name="org.apache.kafka" level="INFO">
<appender-ref ref="file"/>
</logger>
<logger name="org.apache.hadoop" level="INFO">
<appender-ref ref="file"/>
</logger>
<logger name="org.apache.zookeeper" level="INFO">
<appender-ref ref="file"/>
</logger>
<!-- Suppress the irrelevant (wrong) warnings from the Netty channel handler -->
<logger name="org.apache.flink.shaded.akka.org.jboss.netty.channel.DefaultChannelPipeline" level="ERROR">
<appender-ref ref="file"/>
</logger>
</configuration>
2、添加 logback.xml 依赖的jar包（注意版本号与实际使用一致）
添加 log4j-over-slf4j-1.7.25.jar，logback-classic-1.2.3.jar， logback-core-1.2.3.jar 到 $FLINK_HOME/lib 路径下。
此时，配置已经完成。按正常程序启动 flink 任务即可。
二、注意事项
1、该方式只适用于单任务单集群部署方式。
2、$FLINK_HOME/lib/ 下的logback 相关jar 需要与业务项目中logback jar包版本一致。
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版权声明：本文为CSDN博主「Mathieu66」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/Mathieu66/article/details/103905209
