wiki:0428Hadoop_Lab4

Version 1 (modified by waue, 16 years ago) (diff)

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升級

  • 由於換版本的話，資料夾內的conf設定檔也勢必被更改，因此目前作法為： 把conf 移至/opt/conf ，hadoop 0.16 與 hadoop 0.18用 ln 做捷徑代換。由於conf已不在hadoop_home內，因此記得匯入conf/hadoop-env.sh 
    $ source /opt/conf/hadoop-env.sh
  • 先看狀態 
    $ bin/hadoop dfsadmin -upgradeProgress status

There are no upgrades in progress.
  • 停止hdfs
    • 注意不可使用bin/stop-all.sh來停止 
      $ bin/stop-dfs.sh
  • 部署新版本的Hadoop
    • 注意每個node的版本都要統一，否則會出現問題
  • 啟動 
    $ bin/start-dfs.sh -upgrade

ps：之後有介紹到 bin/hadoop namenode -upgrade ，應該要查查看與 $ bin/start-dfs.sh -upgrade 有何不同

  • namenode管理網頁會出現升級狀態

退回

  • 停止集群 
    $ bin/stop-dfs.sh
  • 部署老版本的Hadoop
  • 退回之前版本 
    $ bin/start-dfs.sh -rollback
    ps：之後有介紹到 bin/hadoop namenode -rollback ，應該要查查看與 $ bin/start-dfs.sh -rollback 有何不同

fsck

  • HDFS文件系統檢查工具 
$ bin/hadoop fsck /

.
/user/waue/input/1.txt:  Under replicated blk_-90085106852013388_1001. Target Replicas is 3 but found 2 replica(s).
/user/waue/input/1.txt:  Under replicated blk_-4027196261436469955_1001. Target Replicas is 3 but found 2 replica(s).
.
/user/waue/input/2.txt:  Under replicated blk_-2300843106107816641_1002. Target Replicas is 3 but found 2 replica(s).
.
/user/waue/input/3.txt:  Under replicated blk_-1561577350198661966_1003. Target Replicas is 3 but found 2 replica(s).
.
/user/waue/input/4.txt:  Under replicated blk_1316726598778579026_1004. Target Replicas is 3 but found 2 replica(s).
Status: HEALTHY
 Total size:	143451003 B
 Total dirs:	8
 Total files:	4
 Total blocks (validated):	5 (avg. block size 28690200 B)
 Minimally replicated blocks:	5 (100.0 %)
 Over-replicated blocks:	0 (0.0 %)
 Under-replicated blocks:	5 (100.0 %)
 Mis-replicated blocks:		0 (0.0 %)
 Default replication factor:	3
 Average block replication:	2.0
 Corrupt blocks:		0
 Missing replicas:		5 (50.0 %)
 Number of data-nodes:		2
 Number of racks:		1
The filesystem under path '/' is HEALTHY
  • 加不同的參數有不同的用處，如 
    $ bin/hadoop fsck / -files

/tmp <dir>
/tmp/hadoop <dir>
/tmp/hadoop/hadoop-waue <dir>
/tmp/hadoop/hadoop-waue/mapred <dir>
/tmp/hadoop/hadoop-waue/mapred/system <dir>
/user <dir>
/user/waue <dir>
/user/waue/input <dir>
/user/waue/input/1.txt 115045564 bytes, 2 block(s):  Under replicated blk_-90085106852013388_1001. Target Replicas is 3 but found 2 replica(s).
 Under replicated blk_-4027196261436469955_1001. Target Replicas is 3 but found 2 replica(s).
/user/waue/input/2.txt 987864 bytes, 1 block(s):  Under replicated blk_-2300843106107816641_1002. Target Replicas is 3 but found 2 replica(s).
/user/waue/input/3.txt 1573048 bytes, 1 block(s):  Under replicated blk_-1561577350198661966_1003. Target Replicas is 3 but found 2 replica(s).
/user/waue/input/4.txt 25844527 bytes, 1 block(s):  Under replicated blk_1316726598778579026_1004. Target Replicas is 3 but found 2 replica(s).
Status: HEALTHY
....（同上）

job

  • 用以跟Map Reduce 的作業程序溝通
  • 在測試此指令之前，請確認已經先執行過mapReduce的程序過
  • 可到JobTracker:50030網頁來看程序的Jobid

-status

  • 查看工作狀態 
    $ bin/hadoop job -status job_200904021140_0001

-kill

  • 終止正在執行的程序，其id為 job_200904021140_0001 
    $ bin/hadoop job -kill job_200904021140_0001

-list

  • 印出所有程序的狀態 
    $ bin/hadoop job -list all

5 jobs submitted
States are:
	Running : 1	Succeded : 2	Failed : 3	Prep : 4
JobId	State	StartTime	UserName
job_200904021140_0001	2	1238652150499	waue
job_200904021140_0002	3	1238657754096	waue
job_200904021140_0004	3	1238657989495	waue
job_200904021140_0005	2	1238658076347	waue
job_200904021140_0006	2	1238658644666	waue

-history

  • 印出程序的歷史狀態 
    $ bin/hadoop job -history /user/waue/stream-output1

Hadoop job: job_200904021140_0005
=====================================
Job tracker host name: gm1.nchc.org.tw
job tracker start time: Thu Apr 02 11:40:06 CST 2009
User: waue
JobName: streamjob9019.jar
JobConf: hdfs://gm1.nchc.org.tw:9000/tmp/hadoop/hadoop-waue/mapred/system/job_200904021140_0005/job.xml
Submitted At: 2-四月-2009 15:41:16
Launched At: 2-四月-2009 15:41:16 (0sec)
Finished At: 2-四月-2009 15:42:04 (48sec)
Status: SUCCESS
=====================================
...略

version

  • 印出目前的hadoop 版本 
    bin/hadoop version

Hadoop 0.18.3
Subversion https://svn.apache.org/repos/asf/hadoop/core/branches/branch-0.18 -r 736250
Compiled by ndaley on Thu Jan 22 23:12:08 UTC 2009

HDFS權限管理用戶

  • hdfs的權限有owner, group, other三種
  • 而用戶的身份取決於client上的使用者 （用 whoami），群組為（bash -c groups）
  • 相關的操作： 
    $ bin/hadoop dfs -mkdir own
$ bin/hadoop dfs -chmod -R 755 own
$ bin/hadoop dfs -chgrp -R waue own
$ bin/hadoop dfs -chown -R waue own
$ bin/hadoop dfs -lsr own
  • conf/hadoop-site.xml 可用參數： 
    dfs.permissions = true 
dfs.web.ugi = webuser,webgroup
dfs.permissions.supergroup = supergroup
dfs.upgrade.permission = 777
dfs.umask = 022

-setQuota

  • 目錄配額是對目錄樹上該目錄下的名字數量做硬性限制
  • 設定配額，數字代表個數 （如：我上傳了一個2個block的檔案可以上傳，但我上傳兩個檔案很小的檔上去卻不行）
  • 配額為1可以強制目錄保持為空
  • 重命名不會改變該目錄的配額 
    $ bin/hadoop dfs -mkdir quota
$ bin/hadoop dfsadmin -setQuota 2 quota
$ bin/hadoop dfs -put ../conf/hadoop-env.sh quota/
$ bin/hadoop dfs -put ../conf/hadoop-site.xml quota/

put: org.apache.hadoop.dfs.QuotaExceededException: The quota of /user/waue/quota is exceeded: quota=2 count=3
  • 檢查目錄的配額方法： "bin/hadoop fs -count -q <目錄> " 
$ bin/hadoop fs -count -q own
   none  inf  1    0     0 hdfs://gm1.nchc.org.tw:9000/user/waue/own
$ bin/hadoop dfsadmin -setQuota 4 own
$ bin/hadoop fs -count -q own
    4     3   1    0     0 hdfs://gm1.nchc.org.tw:9000/user/waue/own

-clrQuota

  • 清除之前設定的配額 
    $ bin/hadoop dfsadmin -clrQuota quota/

Hadoop Streaming 函式庫用法

  • Hadoop streaming是Hadoop的一個工具， 它幫助用戶創建和運行一類特殊的map/reduce作業， 這些特殊的map/reduce作業是由一些可執行文件或腳本文件充當mapper或者reducer
  • 最簡單的透過shell執行stream的map reduce: 
    $ bin/hadoop jar hadoop-0.18.3-streaming.jar -input input -output stream-output1 -mapper /bin/cat -reducer /usr/bin/wc
    • 輸出的結果為： (代表 行、字數、字元數) 
      2910628 24507806 143451003