hadoop jps namenode進程沒有啓動

打開logs日誌文件發現有IO異常

2019-04-02 22:07:27,024 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 1, but got txid 120.
	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:898)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:753)
	at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:329)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:983)
	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:686)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:586)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:646)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:820)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.<init>(NameNode.java:804)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1516)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1582)

warn其實不用關心，是hdfs-site.xml沒有用全路徑，但是這個異常時因爲namenode元數據損壞了，
hadoop namenode -recover就ok了