[HDFS-15012] NN fails to parse Edit logs after applying HDFS-13101

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 2.8.0, 2.9.0, 3.1.0, 2.10.0, 3.2.0, 3.3.0
• Component/s: nn
• Labels: release-blocker
• Target Version/s: 3.0.4, 3.3.0, 2.8.6, 2.9.3, 3.1.4, 3.2.2, 2.10.1
• Assignee: Shashikant Banerjee
• Reporter: Eric Lin
• Created: 25/Nov/19 23:23
• Updated: 18/Dec/19 18:12
• Resolved: 18/Dec/19 18:11

Description

After applying HDFS-13101, and deleting and creating large number of snapshots, SNN exited with below error:

2019-11-18 08:28:06,528 ERROR org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader: Encountered exception on operation DeleteSnapshotOp [snapshotRoot=/path/to/hdfs/file, snapshotName=distcp-3479-31-old, RpcClientId=b16a6cb5-bdbb-45ae-9f9a-f7dc57931f37, Rpc
CallId=1]
java.lang.AssertionError: Element already exists: element=partition_isactive=true, DELETED=[partition_isactive=true]
        at org.apache.hadoop.hdfs.util.Diff.insert(Diff.java:193)
        at org.apache.hadoop.hdfs.util.Diff.delete(Diff.java:239)
        at org.apache.hadoop.hdfs.util.Diff.combinePosterior(Diff.java:462)
        at org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature$DirectoryDiff$2.initChildren(DirectoryWithSnapshotFeature.java:240)
        at org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature$DirectoryDiff$2.iterator(DirectoryWithSnapshotFeature.java:250)
        at org.apache.hadoop.hdfs.server.namenode.INodeDirectory.cleanSubtreeRecursively(INodeDirectory.java:755)
        at org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature.cleanDirectory(DirectoryWithSnapshotFeature.java:753)
        at org.apache.hadoop.hdfs.server.namenode.INodeDirectory.cleanSubtree(INodeDirectory.java:790)
        at org.apache.hadoop.hdfs.server.namenode.INodeReference.cleanSubtree(INodeReference.java:332)
        at org.apache.hadoop.hdfs.server.namenode.INodeReference$WithName.cleanSubtree(INodeReference.java:583)
        at org.apache.hadoop.hdfs.server.namenode.INodeDirectory.cleanSubtreeRecursively(INodeDirectory.java:760)
        at org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature.cleanDirectory(DirectoryWithSnapshotFeature.java:753)
        at org.apache.hadoop.hdfs.server.namenode.INodeDirectory.cleanSubtree(INodeDirectory.java:790)
        at org.apache.hadoop.hdfs.server.namenode.snapshot.DirectorySnapshottableFeature.removeSnapshot(DirectorySnapshottableFeature.java:235)
        at org.apache.hadoop.hdfs.server.namenode.INodeDirectory.removeSnapshot(INodeDirectory.java:259)
        at org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotManager.deleteSnapshot(SnapshotManager.java:301)
        at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.applyEditLogOp(FSEditLogLoader.java:688)
        at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadEditRecords(FSEditLogLoader.java:232)
        at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadFSEdits(FSEditLogLoader.java:141)
        at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:903)
        at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:756)
        at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:324)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:1144)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:796)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:614)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:676)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:844)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:823)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1547)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1615)

We confirmed that fsimage and edit files were NOT corrupted, as reverting HDFS-13101 fixed the issue. So the logic introduced in HDFS-13101 is broken and failed to parse edit log files.

Issue Links

• is related to: HDFS-13101 Yet another fsimage corruption related to snapshot