hadoop - AWS EMR 不生成 NameNode FsImage

Question

我们一直在运行一个 3 节点 AWS EMR 集群(1 个 NameNode，2 个 DataNode)。观察到 Namenode 检查点没有发生，fsImage，md5 文件没有更新。编辑日志堆积如山，导致 NameNode 因磁盘空间不足而出现故障。

HDFS 版本:Hadoop 2.8.3-amzn-0

-rw-r--r-- 1 hdfs hdfs        62 Sep  3 12:04 fsimage_0000000000000000000.md5
-rw-r--r-- 1 hdfs hdfs       317 Sep  3 12:04 fsimage_0000000000000000000
-rw-r--r-- 1 hdfs hdfs 260954697 Sep  3 13:49 edits_0000000000000000001-0000000000002061850
-rw-r--r-- 1 hdfs hdfs 270456683 Sep  3 14:54 edits_0000000000002061851-0000000000004196518
-rw-r--r-- 1 hdfs hdfs 256666626 Sep  3 15:54 edits_0000000000004196519-0000000000006223083
-rw-r--r-- 1 hdfs hdfs 256756282 Sep  3 16:54 edits_0000000000006223084-0000000000008250289
-rw-r--r-- 1 hdfs hdfs 263465424 Sep  3 17:59 edits_0000000000008250290-0000000000010330235
-rw-r--r-- 1 hdfs hdfs 257754598 Sep  3 19:49 edits_0000000000010330236-0000000000012365196
-rw-r--r-- 1 hdfs hdfs 257361703 Sep  3 21:39 edits_0000000000012365197-0000000000014396984
-rw-r--r-- 1 hdfs hdfs 258246258 Sep  3 23:29 edits_0000000000014396985-0000000000016435653
-rw-r--r-- 1 hdfs hdfs 257862137 Sep  4 01:19 edits_0000000000016435654-0000000000018471306
-rw-r--r-- 1 hdfs hdfs 257044520 Sep  4 03:09 edits_0000000000018471307-0000000000020496923
-rw-r--r-- 1 hdfs hdfs 256987603 Sep  4 04:59 edits_0000000000020496924-0000000000022520948
-rw-r--r-- 1 hdfs hdfs 254213703 Sep  4 06:44 edits_0000000000022520949-0000000000024522780
-rw-r--r-- 1 hdfs hdfs 265518336 Sep  4 08:34 edits_0000000000024522781-0000000000026613243

根据 Hadoop 2.8.3

The Secondary NameNode or CheckpointNode will create a checkpoint of the namespace every 'dfs.namenode.checkpoint.txns'(Default -100000) transactions, regardless of whether 'dfs.namenode.checkpoint.period' (Default - 3600 secs) has expired.

但是检查点并没有发生在 Namenode 中

Answer 1

您可以运行以下命令来使 NameNode 工作作为解决方法:

   hdfs dfsadmin -safemode enter  
   hdfs dfsadmin -saveNamespace  
   hdfs dfsadmin -safemode leave

https://community.hortonworks.com/content/supportkb/49438/how-to-manually-checkpoint.html