Explanation
* Correct answer is To directly reference one shared and customized log4j2.xml file from multiple Mule applications. Key word to note in the answer is directly.
* By default, CloudHub replaces a Mule application's log4j2.xml file with a CloudHub log4j2.xml file. This specifies the CloudHub appender to write logs to the CloudHub logging service.
* You cannot modify CloudHub log4j2.xml file to add any custom appender. But there is a process in order to achieve this. You need to raise a request on support portal to disable CloudHub provided Mule application log4j2 file.
* Once this is done , Mule application's log4j2.xml file is used which you can use to send/export application logs to other log4j2 appenders, such as a custom logging system MuleSoft does not own any responsibility for lost logging data due to misconfiguration of your own log4j appender if it happens by any chance.
* One more difference between customer-hosted Mule runtimes and CloudHub deployed mule instance is that
- CloudHub system log messages cannot be sent to external log management system without installing custom CH logging configuration through support
- where as Customer-hosted runtime can send system and application log to external log management system
MuleSoft Reference:
https://docs.mulesoft.com/runtime-manager/viewing-log-data
https://docs.mulesoft.com/runtime-manager/custom-log-appender