Xiao Chen created HADOOP-15317: ---------------------------------- Summary: Improve NetworkTopology chooseRandom's loop Key: HADOOP-15317 URL: https://issues.apache.org/jira/browse/HADOOP-15317 Project: Hadoop Common Issue Type: Bug Reporter: Xiao Chen Assignee: Xiao Chen
Recently we found a postmortem case where the ANN seems to be in an infinite loop. From the logs it seems it just went through a rolling restart, and DNs are getting registered. Later the NN become unresponsive, and from the stacktrace it's inside a do-while loop inside {{NetworkTopology#chooseRandom}} - part of what's done in HDFS-10320. Going through the code and logs I'm not able to come up with any theory (thought about incorrect locking, or the Node object being modified outside of NetworkTopology, both seem impossible) why this is happening, but we should eliminate this loop. stacktrace: {noformat} Stack: java.util.HashMap.hash(HashMap.java:338) java.util.HashMap.containsKey(HashMap.java:595) java.util.HashSet.contains(HashSet.java:203) org.apache.hadoop.net.NetworkTopology.chooseRandom(NetworkTopology.java:786) org.apache.hadoop.net.NetworkTopology.chooseRandom(NetworkTopology.java:732) org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseDataNode(BlockPlacementPolicyDefault.java:757) org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseRandom(BlockPlacementPolicyDefault.java:692) org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseRandom(BlockPlacementPolicyDefault.java:666) org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseLocalRack(BlockPlacementPolicyDefault.java:573) org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTargetInOrder(BlockPlacementPolicyDefault.java:461) org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTarget(BlockPlacementPolicyDefault.java:368) org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTarget(BlockPlacementPolicyDefault.java:243) org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault.chooseTarget(BlockPlacementPolicyDefault.java:115) org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.chooseTarget4AdditionalDatanode(BlockManager.java:1596) org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getAdditionalDatanode(FSNamesystem.java:3599) org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.getAdditionalDatanode(NameNodeRpcServer.java:717) {noformat} -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: common-dev-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-dev-h...@hadoop.apache.org