Changes between Initial Version and Version 1 of Hadoop_Lab8

Timestamp:

Aug 28, 2009, 6:14:47 PM (15 years ago)

Author:

waue

Comment:

--

Hadoop_Lab8

@@ +1 @@
+{{{
+#!html
+<div style="text-align: center;"><big
+ style="font-weight: bold;"><big><big>實作四： Hadoop 叢集進階用法 </big></big></big></div>
+}}}
+[[PageOutline]]
+
+= 狀況一： 如何動態加入datanode 與 tasktracker = 
+ * 某些情況下，後來的環境也許會跟之前配置的不同，比如說，原本只有五台機器架設hadoop，但是也許老闆今天心血來潮，又撥了五台電腦給你。在接續之前的環境動態的擴增節點的方法，請看以下作法。
+
+== 1.0 說明 ==
+
+ * 要新增的節點上，hadoop版本與設定檔要與原先的相同
+ * 是否能連到正確的位址取決於conf/hadoop-site.xml內的jobTracker, Namenode資訊是否正確  (目前測試結果與conf/slave、masters無關)
+
+== 1.1 加入datanode == 
+
+ * 在要加入的節點上面下此指令
+{{{
+$ cd $HADOOP_HOME
+$ bin/hadoop-daemon.sh --config ./conf start datanode
+}}}
+   * 執行畫面如下：
+{{{
+starting datanode, logging to /tmp/hadoop/logs/hadoop-waue-datanode-Dx7200.out
+}}}
+
+== 1.2 加入 taskTracker == 
+
+ * 是否能連到正確的namenode取決於conf/hadoop-site.xml，目前測試結果與conf/slave、masters無關
+{{{
+$ cd $HADOOP_HOME
+$ bin/hadoop-daemon.sh --config ./conf start tasktracker
+}}}
+   * 執行畫面如下：
+{{{
+starting tasktracker, logging to /tmp/hadoop/logs/hadoop-waue-tasktracker-Dx7200.out
+}}}
+
+-----
+
+= 狀況二： 怎麼讓我的HDFS內資料均勻分散於各個Node上 = 
+
+ * 下面指令用於分析數據塊分佈和重新平衡!DataNode上的數據分佈
+{{{
+$ bin/hadoop balancer
+}}}
+   * 執行畫面如下
+{{{
+Time Stamp               Iteration#  Bytes Already Moved  Bytes Left To Move  Bytes Being Moved
+09/04/01 18:00:08 INFO net.NetworkTopology: Adding a new node: /default-rack/140.110.138.191:50010
+09/04/01 18:00:08 INFO net.NetworkTopology: Adding a new node: /default-rack/140.110.141.129:50010
+09/04/01 18:00:08 INFO dfs.Balancer: 0 over utilized nodes:
+09/04/01 18:00:08 INFO dfs.Balancer: 0 under utilized nodes: 
+The cluster is balanced. Exiting...
+Balancing took 186.0 milliseconds
+}}}
+
+------
+
+= 狀況三：如何讓已上線服務的Hadoop進行升級並且不失去以前的資料 =
+
+ * 假設從原本的hadoop 0.16升級到hadoop 0.18
+ * 如果把conf/這個資料夾至於$Hadoop_home目錄下的話，一旦換版本就連conf也被一併換掉，但無論hadoop的版本新舊，其實設定檔及其資訊是可以共用的。
+
+== step 1. 停止hdfs ==
+
+ * 先看狀態
+{{{
+$ cd /opt/hadoop/
+$ 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
+}}}
+
+== Step 2. 鍊結新版本hadoop == 
+
+ * 把conf 移至/opt/conf ，hadoop 0.16 與 hadoop 0.18用 ln 做捷徑代換。
+ * 以下假設你已經下載好hadoop0.18並解壓縮後，資料夾名稱為hadoop-0.18.3
+{{{
+$ cd opt/
+$ mv hadoop/conf ./
+$ mv hadoop hadoop-0.16
+$ ln hadoop-0.18.3 hadoop
+}}}
+
+== step 3. 設置環境變數　==
+
+ * 由於conf已不在hadoop_home內，因此記得匯入conf/hadoop-env.sh的參數
+ * 填入hadoop-env.sh 內$HADOOP_CONF_DIR正確路徑，並匯入資訊
+{{{
+$ source /opt/conf/hadoop-env.sh
+}}}
+
+== step 4. 每個節點都部署新版本的Hadoop ==
+
+ * 若有多個node的話，則每個node的hadoop版本都要統一，否則會出現問題
+
+== step 5. 啟動 == 
+
+{{{
+$ bin/start-dfs.sh -upgrade
+}}}
+
+ * namenode管理網頁會出現升級狀態
+
+-------
+
+= 狀況四：如何讓已上線服務的Hadoop進行降級並且不失去以前的資料 =
+
+ * 此情況與狀況三相反，因此作法類似狀況三，下面的狀況假設設定檔已在/opt/conf內，並且/opt內也都有hadoop-0.16 與 hadoop-0.18.3 兩個資料夾，而且節點只有一台。
+
+== step 1. 停止 HDFS ==
+
+{{{
+$ cd /opt/hadoop
+$ bin/stop-dfs.sh
+}}}
+
+== step 2. 部署老版本的Hadoop == 
+
+{{{
+$ rm /opt/hadoop
+$ ln hadoop-0.16 hadoop
+}}}
+
+== step 3. 退回之前版本 ==
+
+{{{
+$ bin/start-dfs.sh -rollback
+}}}
+
+-----
+
+= 狀況五：我的HDFS檔案系統是否正常 =
+
+ * 在此介紹HDFS文件系統檢查工具 "bin/hadoop fsck"
+
+{{{
+$ bin/hadoop fsck /
+}}}
+   * 執行畫面如下
+{{{
+.
+/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
+}}}
+   * 執行畫面如下
+{{{
+/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）
+}}}
+
+-----
+
+= 狀況六：我的系統似乎跑太多Job，我要幫他減肥 = 
+
+== step 1. 把所有程序列出來 ==
+
+ * 可到JobTracker:50030網頁來看程序的Jobid
+ * 或用指令印出所有程序
+{{{
+$ 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
+}}}
+
+== step 2. more detail ==
+
+ * 查看工作狀態
+{{{
+$ bin/hadoop job -status job_200904021140_0001
+}}}
+ * 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
+}}}
+
+== step 3. 殺很大、殺不用錢 ==
+
+ * 終止正在執行的程序，如 id 為 job_200904021140_0001
+{{{
+$ bin/hadoop job -kill job_200904021140_0001
+}}}
+--------
+
+= 狀況七：怎麼看目前的Hadoop版本 =
+
+ * 印出目前的hadoop 版本
+{{{
+$ bin/hadoop version
+}}}
+   * 執行畫面
+{{{
+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
+}}}
+
+-----
+= 狀況八：我要設定HDFS的帳戶及配額 =
+
+== step 1. 先設定各使用者的預設資料夾，屬性及讀寫權限 ==
+
+ * 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 fs -mkdir own
+$ bin/hadoop fs -chmod -R 755 own
+$ bin/hadoop fs -chgrp -R waue own
+$ bin/hadoop fs -chown -R waue own
+$ bin/hadoop fs -lsr own
+}}}
+ * conf/hadoop-site.xml 可用參數：
+{{{
+#!php
+dfs.permissions = true 
+dfs.web.ugi = webuser,webgroup
+dfs.permissions.supergroup = supergroup
+dfs.upgrade.permission = 777
+dfs.umask = 022
+}}}
+
+== step 2. 設定配額 ==
+
+ * 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 fs -mkdir quota
+$ bin/hadoop dfsadmin -setQuota 2 quota
+$ bin/hadoop fs -put ../conf/hadoop-env.sh quota/
+$ bin/hadoop fs -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
+}}}
+
+ * 清除之前設定的配額
+{{{
+$ bin/hadoop dfsadmin -clrQuota quota/
+}}}