Andrew Johnson created YARN-3364: ------------------------------------ Summary: Clarify Naming of yarn.client.nodemanager-connect.max-wait-ms and yarn.resourcemanager.connect.max-wait.ms Key: YARN-3364 URL: https://issues.apache.org/jira/browse/YARN-3364 Project: Hadoop YARN Issue Type: Improvement Components: yarn Reporter: Andrew Johnson
I encountered an issue recently where the ApplicationMaster for MapReduce jobs would spend hours attempting to connect to a node in my cluster that had died due to a hardware fault. After debugging this, I found that the yarn.client.nodemanager-connect.max-wait-ms property did not behave as I had expected. Based on the name I had thought this would set a maximum time limit for attempting to connect to a NodeManager. The code in org.apache.hadoop.yarn.client.NMProxy corroborated this thought - it used a RetryUpToMaximumTimeWithFixedSleep policy when a ConnectTimeoutException was thrown, as it was in my case with a dead node. However, the RetryUpToMaximumTimeWithFixedSleep policy doesn't actually set a time limit, but instead divides the maximum time by the sleep period to set a total number of retries, regardless of how long those retries take. As such I was seeing the ApplicationMaster spend much longer attempting to make a connection than I had anticipated. The yarn.resourcemanager.connect.max-wait.ms would have the same behavior. These properties would be better named like yarn.client.nodemanager-connect.max.retries and yarn.resourcemanager.connect.max.retries to better align with the actual behavior. -- This message was sent by Atlassian JIRA (v6.3.4#6332)