第2章 Hadoop快速入门

2.4 Hadoop单机运行

紧接上一节内容，首先切换到Hadoop根目录

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或者cd /opt/hadoop-2.7.3进入Hadoop根目录
通过pwd命令可以知道当前所在目录

[root@node1 hadoop-2.7.3]# pwd

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注意：本节命令都将在/opt/hadoop-2.7.3目录下执行。

2.4.1 namenode格式化

执行bin/hadoop namenode -format命令，进行namenode格式化

[root@node1 hadoop-2.7.3]# bin/hadoop namenode -format

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输出信息(下半部分)：

17/05/12 05:59:11 INFO namenode.NameNode: registered UNIX signal handlers for [TERM, HUP, INT]
17/05/12 05:59:11 INFO namenode.NameNode: createNameNode [-format]
Formatting using clusterid: CID-db9a34c9-661e-4fc0-a273-b554e0cfb32b
17/05/12 05:59:12 INFO namenode.FSNamesystem: No KeyProvider found.
17/05/12 05:59:12 INFO namenode.FSNamesystem: fsLock is fair:true
17/05/12 05:59:12 INFO blockmanagement.DatanodeManager: dfs.block.invalidate.limit=1000
17/05/12 05:59:12 INFO blockmanagement.DatanodeManager: dfs.namenode.datanode.registration.ip-hostname-check=true
17/05/12 05:59:12 INFO blockmanagement.BlockManager: dfs.namenode.startup.delay.block.deletion.sec is set to 000:00:00:00.000
17/05/12 05:59:12 INFO blockmanagement.BlockManager: The block deletion will start around 2017 May 12 05:59:12
17/05/12 05:59:12 INFO util.GSet: Computing capacity for map BlocksMap
17/05/12 05:59:12 INFO util.GSet: VM type       = 64-bit
17/05/12 05:59:12 INFO util.GSet: 2.0% max memory 966.7 MB = 19.3 MB
17/05/12 05:59:12 INFO util.GSet: capacity      = 2^21 = 2097152 entries
17/05/12 05:59:12 INFO blockmanagement.BlockManager: dfs.block.access.token.enable=false
17/05/12 05:59:12 INFO blockmanagement.BlockManager: defaultReplication         = 1
17/05/12 05:59:12 INFO blockmanagement.BlockManager: maxReplication             = 512
17/05/12 05:59:12 INFO blockmanagement.BlockManager: minReplication             = 1
17/05/12 05:59:12 INFO blockmanagement.BlockManager: maxReplicationStreams      = 2
17/05/12 05:59:12 INFO blockmanagement.BlockManager: replicationRecheckInterval = 3000
17/05/12 05:59:12 INFO blockmanagement.BlockManager: encryptDataTransfer        = false
17/05/12 05:59:12 INFO blockmanagement.BlockManager: maxNumBlocksToLog          = 1000
17/05/12 05:59:12 INFO namenode.FSNamesystem: fsOwner             = root (auth:SIMPLE)
17/05/12 05:59:12 INFO namenode.FSNamesystem: supergroup          = supergroup
17/05/12 05:59:12 INFO namenode.FSNamesystem: isPermissionEnabled = true
17/05/12 05:59:12 INFO namenode.FSNamesystem: HA Enabled: false
17/05/12 05:59:12 INFO namenode.FSNamesystem: Append Enabled: true
17/05/12 05:59:13 INFO util.GSet: Computing capacity for map INodeMap
17/05/12 05:59:13 INFO util.GSet: VM type       = 64-bit
17/05/12 05:59:13 INFO util.GSet: 1.0% max memory 966.7 MB = 9.7 MB
17/05/12 05:59:13 INFO util.GSet: capacity      = 2^20 = 1048576 entries
17/05/12 05:59:13 INFO namenode.FSDirectory: ACLs enabled? false
17/05/12 05:59:13 INFO namenode.FSDirectory: XAttrs enabled? true
17/05/12 05:59:13 INFO namenode.FSDirectory: Maximum size of an xattr: 16384
17/05/12 05:59:13 INFO namenode.NameNode: Caching file names occuring more than 10 times
17/05/12 05:59:13 INFO util.GSet: Computing capacity for map cachedBlocks
17/05/12 05:59:13 INFO util.GSet: VM type       = 64-bit
17/05/12 05:59:13 INFO util.GSet: 0.25% max memory 966.7 MB = 2.4 MB
17/05/12 05:59:13 INFO util.GSet: capacity      = 2^18 = 262144 entries
17/05/12 05:59:13 INFO namenode.FSNamesystem: dfs.namenode.safemode.threshold-pct = 0.9990000128746033
17/05/12 05:59:13 INFO namenode.FSNamesystem: dfs.namenode.safemode.min.datanodes = 0
17/05/12 05:59:13 INFO namenode.FSNamesystem: dfs.namenode.safemode.extension     = 30000
17/05/12 05:59:13 INFO metrics.TopMetrics: NNTop conf: dfs.namenode.top.window.num.buckets = 10
17/05/12 05:59:13 INFO metrics.TopMetrics: NNTop conf: dfs.namenode.top.num.users = 10
17/05/12 05:59:13 INFO metrics.TopMetrics: NNTop conf: dfs.namenode.top.windows.minutes = 1,5,25
17/05/12 05:59:13 INFO namenode.FSNamesystem: Retry cache on namenode is enabled
17/05/12 05:59:13 INFO namenode.FSNamesystem: Retry cache will use 0.03 of total heap and retry cache entry expiry time is 600000 millis
17/05/12 05:59:13 INFO util.GSet: Computing capacity for map NameNodeRetryCache
17/05/12 05:59:13 INFO util.GSet: VM type       = 64-bit
17/05/12 05:59:13 INFO util.GSet: 0.029999999329447746% max memory 966.7 MB = 297.0 KB
17/05/12 05:59:13 INFO util.GSet: capacity      = 2^15 = 32768 entries
17/05/12 05:59:13 INFO namenode.FSImage: Allocated new BlockPoolId: BP-2055065474-192.168.80.131-1494583153319
17/05/12 05:59:13 INFO common.Storage: Storage directory /tmp/hadoop-root/dfs/name has been successfully formatted.
17/05/12 05:59:13 INFO namenode.FSImageFormatProtobuf: Saving image file /tmp/hadoop-root/dfs/name/current/fsimage.ckpt_0000000000000000000 using no compression
17/05/12 05:59:13 INFO namenode.FSImageFormatProtobuf: Image file /tmp/hadoop-root/dfs/name/current/fsimage.ckpt_0000000000000000000 of size 351 bytes saved in 0 seconds.
17/05/12 05:59:13 INFO namenode.NNStorageRetentionManager: Going to retain 1 images with txid >= 0
17/05/12 05:59:13 INFO util.ExitUtil: Exiting with status 0
17/05/12 05:59:13 INFO namenode.NameNode: SHUTDOWN_MSG: 
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at node1/192.168.80.131
************************************************************/

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在执行结果中可以找到has been successfully formatted，说明namenode格式化成功了！

2.4.2 启动HDFS

执行sbin/start-dfs.sh命令启动HDFS

[root@node1 hadoop-2.7.3]# sbin/start-dfs.sh
Starting namenodes on [node1]
node1: starting namenode, logging to /opt/hadoop-2.7.3/logs/hadoop-root-namenode-node1.out
localhost: starting datanode, logging to /opt/hadoop-2.7.3/logs/hadoop-root-datanode-node1.out
Starting secondary namenodes [0.0.0.0]
The authenticity of host '0.0.0.0 (0.0.0.0)' can't be established.
ECDSA key fingerprint is e2:9a:7d:70:25:24:45:11:97:12:35:e0:45:4c:64:31.
Are you sure you want to continue connecting (yes/no)? yes
0.0.0.0: Warning: Permanently added '0.0.0.0' (ECDSA) to the list of known hosts.
0.0.0.0: starting secondarynamenode, logging to /opt/hadoop-2.7.3/logs/hadoop-root-secondarynamenode-node1.out

在启动HDFS过程中，按照提示输入“yes”
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通过jps命令可以查看Java进程

[root@node1 hadoop-2.7.3]# jps

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jps(Java Virtual Machine Process Status Tool)是JDK 1.5开始提供的一个显示当前所有Java进程pid的命令，简单实用，非常适合在Linux/unix平台上简单察看当前java进程的一些简单情况。
jps -l输出应用程序main class的完整package名或者应用程序的jar文件完整路径名

[root@node1 ~]# jps -l
5752 sun.tools.jps.Jps
5342 org.apache.hadoop.hdfs.server.namenode.NameNode
5440 org.apache.hadoop.hdfs.server.datanode.DataNode
5630 org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode

2.4.3 启动YARN

通过命令sbin/start-yarn.sh启动YARN

[root@node1 hadoop-2.7.3]# sbin/start-yarn.sh
starting yarn daemons
starting resourcemanager, logging to /opt/hadoop-2.7.3/logs/yarn-root-resourcemanager-node1.out
localhost: starting nodemanager, logging to /opt/hadoop-2.7.3/logs/yarn-root-nodemanager-node1.out

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然后通过jps查看YARN的进程

[root@node1 hadoop-2.7.3]# jps
5440 DataNode
7253 ResourceManager
7351 NodeManager
5342 NameNode
5630 SecondaryNameNode
7662 Jps

[root@node1 hadoop-2.7.3]#