cloudstack中的log4j配置文件类型

Question

I am studying the logging structure used with CloudStack. I understand that it uses log4j to do the logging. log4j requires the use of configuration files to control what to log and where to log it. What I found is that the there was a combination of several log configuration files accross the log4j project along with the properties files that can be used to perform the tasks of a configuration file. What I want to understand is as follow:

1- CloudStack contains two types of configuration files which are "log4j-cloud.xml" and "log4j-cloud.xml.in". these two types of files are spread accross different projects and dosent contain the same information. What is the difference between these files, and what the "in" stand for.

2- What is being used by log4j to specify what to log and where to log it. Is it the cofiguration file or the properties file.

Answer 1

1. The log4j-cloud.xml.in is the configuration file for console logging. This is where you should be setting your configuration

2. log4j is used for cloudstack exception logging and the log4j.xml file is where you would configure that. You can find more information about cloudstack exception logging using log4j here https://cwiki.apache.org/confluence/display/CLOUDSTACK/Exceptions+and+logging