报错:hadoop There appears to be a gap in the edit log. We expected txid 927, but got txid 1265.

报错背景

hadoop启动报错。

报错现象

Number of suppressed write-lock reports: 0
    Longest write-lock held interval: 10734
2020-12-15 10:48:07,720 WARN org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Encountered exception loading fsimage
java.io.IOException: There appears to be a gap in the edit log.  We expected txid 927, but got txid 1265.
    at org.apache.hadoop.hdfs.server.namenode.MetaRecoveryContext.editLogLoaderPrompt(MetaRecoveryContext.java:94)
    at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadEditRecords(FSEditLogLoader.java:215)
    at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadFSEdits(FSEditLogLoader.java:143)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:890)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:745)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:321)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:978)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:685)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:585)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:645)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:819)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:803)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1500)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1566)
2020-12-15 10:48:07,722 INFO org.mortbay.log: Stopped HttpServer2$SelectChannelConnectorWithSafeStartup@bigdata01:50070
2020-12-15 10:48:07,823 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Stopping NameNode metrics system...
2020-12-15 10:48:07,823 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: NameNode metrics system stopped.
2020-12-15 10:48:07,823 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: NameNode metrics system shutdown complete.
2020-12-15 10:48:07,823 ERROR org.apache.hadoop.hdfs.server.namenode.NameNode: Failed to start namenode.
java.io.IOException: There appears to be a gap in the edit log.  We expected txid 927, but got txid 1265.
    at org.apache.hadoop.hdfs.server.namenode.MetaRecoveryContext.editLogLoaderPrompt(MetaRecoveryContext.java:94)
    at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadEditRecords(FSEditLogLoader.java:215)
    at org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadFSEdits(FSEditLogLoader.java:143)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:890)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:745)
    at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:321)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:978)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:685)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:585)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:645)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:819)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:803)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1500)
    at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1566)
2020-12-15 10:48:07,825 INFO org.apache.hadoop.util.ExitUtil: Exiting with status 1
2020-12-15 10:48:07,825 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: SHUTDOWN_MSG: 

报错原因

上面日志提示 We expected txid 927, but got txid 1265 也就是Namenode想要获取927这个edit，但是获取到的是1265，查看 jn 目录下，发现的确只有1265 即：edits_0000000000000001265-0000000000000001265

报错解决

（1）方法一：命令修复元数据

# hadoop namenode -recover

遇到 (Y/N) 选Y

遇到 (c/s/q/a) 选c

重启hadoop即可。

（2）方法二：复制缺失文件

hadoop集群下会有两个JournalNode，可以将另一个节点存在，而此节点不存在的文件使用scp命令复制过来，

文件所在目录是自定义的，例如：/data/hadoop/hdfs/journal/cluster/current

# scp edits_0000000000000000041-0000000000000000043 root@bigdata01:/data/hadoop/hdfs/journal/cluster/current

# hdfs zkfc -formatZK

重启hadoop即可。