HDP's build of Storm comes bundled with a custom logback configuration file which you can find and view under https://github.com/hortonworks/storm-release/blob/HDP-126.96.36.199-tag/logback/cluster.xml. It has an appender configured called METRICS that is used whenever you configure a metrics consumer with a topology to write out topology metrics. This appender is configured to use a FixedWindowRollingPolicy, which per the Logback documentation does not support prudent mode and therefore is not capable of allowing two processes to log to the same file. This is a problem whenever two topologies run on the same host because both workers must be able to log to /var/log/storm/metrics.log. I'm not sure how to circumvent this problem. I've tried using a custom logback.xml and deploying the topology with -Dlogback.configurationFile, but that seemed to cause unintended consequences with the other log files.