hadoop 常见的运维命令 hdfs fsck

 hadoop2.x主要分为hdfs和yarn

与hdfs上相关的角色：namenode（高可用情况下有2个）、datanode（若干个）、journal node（奇数个，一般为3个，用于高可用集群故障转移）、Failover Controller （这个角色向下监控name node，向上向zookeeper反映namenode的健康状态）httpfs（httpfs是一个hadoop hdfs的一个http接口，通过WebHDFS REST API 可以对hdfs进行读写等访问，可用于hue使用高可用的hdfs集群）。

Usage: hdfs [--config confdir] [--loglevel loglevel] COMMAND
       where COMMAND is one of:
  dfs                  run a filesystem command on the file systems supported in Hadoop.
  classpath            prints the classpath
  namenode -format     format the DFS filesystem
  secondarynamenode    run the DFS secondary namenode
  namenode             run the DFS namenode
  journalnode          run the DFS journalnode
  zkfc                 run the ZK Failover Controller daemon
  datanode             run a DFS datanode
  dfsadmin             run a DFS admin client
  haadmin              run a DFS HA admin client
  fsck                 run a DFS filesystem checking utility
  balancer             run a cluster balancing utility
  jmxget               get JMX exported values from NameNode or DataNode.
  mover                run a utility to move block replicas across
                       storage types
  oiv                  apply the offline fsimage viewer to an fsimage
  oiv_legacy           apply the offline fsimage viewer to an legacy fsimage
  oev                  apply the offline edits viewer to an edits file
  fetchdt              fetch a delegation token from the NameNode
  getconf              get config values from configuration
  groups               get the groups which users belong to
  snapshotDiff         diff two snapshots of a directory or diff the
                       current directory contents with a snapshot
  lsSnapshottableDir   list all snapshottable dirs owned by the current user
                                                Use -help to see options
  portmap              run a portmap service
  nfs3                 run an NFS version 3 gateway
  cacheadmin           configure the HDFS cache
  crypto               configure HDFS encryption zones
  storagepolicies      list/get/set block storage policies
  version              print the version
　　

 检查hdfs 文件健康状态

[dip@dip001 ~]$ hdfs fsck /test/test.txt
Connecting to namenode via http://dip001:50070
FSCK started by dip (auth:SIMPLE) from /172.21.25.127 for path /test/test.txt at Wed Nov 28 10:05:24 CST 2018
#健康状态
.Status: HEALTHY
#总的大小
 Total size:    1431 B

 Total dirs:    0
 Total files:    1
 Total symlinks:        0
 Total blocks (validated):    1 (avg. block size 1431 B)
 Minimally replicated blocks:    1 (100.0 %)
 Over-replicated blocks:    0 (0.0 %)
 Under-replicated blocks:    0 (0.0 %)
 Mis-replicated blocks:        0 (0.0 %)
 Default replication factor:    3
 Average block replication:    3.0
 Corrupt blocks:        0
 Missing replicas:        0 (0.0 %)
 Number of data-nodes:        3
 Number of racks:        1
FSCK ended at Wed Nov 28 10:05:24 CST 2018 in 1 milliseconds


The filesystem under path '/test/test.txt is HEALTHY