When setting up the capacity scheduler users are faced with problems like:
Which basically arises from missing basic configurations, which in many cases, there is no need to explicitly provide, and a default configuration will be sufficient. For example, to address the error above, the user need to add a capacity of 100 to the root queue.
So, we need to add a capacity-scheduler-default.xml, this will be helpful to provide the basic set of default configurations required to run the capacity scheduler. The user can still override existing configurations or provide new ones in capacity-scheduler.xml. This is similar to *-default.xml vs *-site.xml for yarn, core, mapred, hdfs, etc.