RocketMQLog:WARN No appenders could be found for logger (io.netty.channel.nio.NioEventLoop).

This warning message indicates that the logging system for RocketMQ could not find any appenders for the specified logger, which in this case is io.netty.channel.nio.NioEventLoop.

An appender is a component of the logging system that determines where log messages are written, such as to a file or console output. Without any appenders, log messages will not be written to any destination, which can make it difficult to diagnose issues.

To resolve this warning, you should configure an appender for the specified logger or for the entire logging system. This can typically be done by editing the log4j.properties or logback.xml configuration file, depending on which logging framework is being used.