练习环境：
操作系统：Ubuntu 16.04 LTS
Hadoop版本：Hadoop 2.7.1
1.配置core-site.xml
hadoop@dblab:/usr/local/hadoop/etc/hadoop$ vim core-site.xml
2.配置hdfs-site.xml
hadoop@dblab:/usr/local/hadoop/etc/hadoop$ vim hdfs-site.xml
3.执行名称节点格式化
hadoop@dblab:/usr/local/hadoop$
hadoop@dblab:/usr/local/hadoop$ ./bin/hdfs namenode –format
Re-format filesystem in Storage Directory /usr/local/hadoop/tmp/dfs/name ? (Y or N)
19/05/16 14:23:44 INFO namenode.FSImage: Allocated new BlockPoolId: BP-748770776-127.0.0.1-1557987824492
19/05/16 14:23:44 INFO common.Storage: Storage directory /usr/local/hadoop/tmp/dfs/name has been successfully formatted.
19/05/16 14:23:45 INFO namenode.NNStorageRetentionManager: Going to retain 1 images with txid >= 0
19/05/16 14:23:45 INFO util.ExitUtil: Exiting with status 0
19/05/16 14:23:45 INFO namenode.NameNode: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down NameNode at java.net.UnknownHostException: dblab: dblab: 未知的名称或服务
************************************************************/
解释上述问题:
hadoop@dblab:/usr/local/hadoop$ hostname
dblab
hadoop@dblab:/usr/local/hadoop$ cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 dblab-VirtualBox
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
hadoop@dblab:/usr/local/hadoop$ sudo vim /etc/hosts
127.0.1.1 dblab
hadoop@dblab:/usr/local/hadoop$ sudo /etc/init.d/networking restart
4.启动Hadoop
hadoop@dblab:/usr/local/hadoop$ ./sbin/start-dfs.sh
Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/local/hadoop/logs/hadoop-hadoop-namenode-dblab.out
localhost: starting datanode, logging to /usr/local/hadoop/logs/hadoop-hadoop-datanode-dblab.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-hadoop-secondarynamenode-dblab.out
#以上是启动失败
hadoop@dblab:/usr/local/hadoop$ ./sbin/start-dfs.sh
Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/local/hadoop/logs/hadoop-hadoop-namenode-dblab.out
localhost: starting datanode, logging to /usr/local/hadoop/logs/hadoop-hadoop-datanode-dblab.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-hadoop-secondarynamenode-dblab.out
HDFS的Web管理界面
5.运行Hadoop伪分布式实例
hadoop@dblab:/usr/local/hadoop$ cd /usr/local/hadoop
hadoop@dblab:/usr/local/hadoop$ ./bin/hdfs dfs -mkdir -p /user/hadoop
hadoop@dblab:/usr/local/hadoop$ ./bin/hdfs dfs -mkdir input
hadoop@dblab:/usr/local/hadoop$ ./bin/hdfs dfs -put ./etc/hadoop/*.xml input
hadoop@dblab:/usr/local/hadoop$ ./bin/hdfs dfs -ls input
Found 8 items
-rw-r--r-- 1 hadoop supergroup 4436 2019-05-16 14:52 input/capacity-scheduler.xml
-rw-r--r-- 1 hadoop supergroup 965 2019-05-16 14:52 input/core-site.xml
-rw-r--r-- 1 hadoop supergroup 9683 2019-05-16 14:52 input/hadoop-policy.xml
-rw-r--r-- 1 hadoop supergroup 1080 2019-05-16 14:52 input/hdfs-site.xml
-rw-r--r-- 1 hadoop supergroup 620 2019-05-16 14:52 input/httpfs-site.xml
-rw-r--r-- 1 hadoop supergroup 3518 2019-05-16 14:52 input/kms-acls.xml
-rw-r--r-- 1 hadoop supergroup 5511 2019-05-16 14:52 input/kms-site.xml
-rw-r--r-- 1 hadoop supergroup 690 2019-05-16 14:52 input/yarn-site.xml
hadoop@dblab:/usr/local/hadoop$ ./bin/hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar grep input output 'dfs[a-z.]+'
hadoop@dblab:/usr/local/hadoop$ ./bin/hdfs dfs -cat output/*
1 dfsadmin
1 dfs.replication
1 dfs.namenode.name.dir
1 dfs.datanode.data.dir
6.关闭Hadoop
hadoop@dblab:/usr/local/hadoop$ ./sbin/stop-dfs.sh #关闭Hadoop
7.启动YARN
$./sbin/start-dfs.sh
hadoop@dblab:/usr/local/hadoop$ vim /usr/local/hadoop/etc/hadoop/yarn-site.xml
hadoop@dblab:/usr/local/hadoop$ ./sbin/start-dfs.sh
Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/local/hadoop/logs/hadoop-hadoop-namenode-dblab.out
localhost: starting datanode, logging to /usr/local/hadoop/logs/hadoop-hadoop-datanode-dblab.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-hadoop-secondarynamenode-dblab.out
hadoop@dblab:/usr/local/hadoop$ ./sbin/start-dfs.sh
Starting namenodes on [localhost]
localhost: namenode running as process 28914. Stop it first.
localhost: datanode running as process 29067. Stop it first.
Starting secondary namenodes [0.0.0.0]
0.0.0.0: secondarynamenode running as process 29261. Stop it first.
hadoop@dblab:/usr/local/hadoop$ vim ./etc/hadoop/mapred-site.xml
hadoop@dblab:/usr/local/hadoop$ vim ./etc/hadoop/yarn-site.xml
hadoop@dblab:/usr/local/hadoop$ ./sbin/start-yarn.sh #启动YARN
starting yarn daemons
starting resourcemanager, logging to /usr/local/hadoop/logs/yarn-hadoop-resourcemanager-dblab.out
localhost: starting nodemanager, logging to /usr/local/hadoop/logs/yarn-hadoop-nodemanager-dblab.out
hadoop@dblab:/usr/local/hadoop$ ./sbin/mr-jobhistory-daemon.sh start historyserver #开启历史服务器
starting historyserver, logging to /usr/local/hadoop/logs/mapred-hadoop-historyserver-dblab.out
hadoop@dblab:/usr/local/hadoop$ jps #查看进程
29809 ResourceManager
28034 RunJar
28914 NameNode
30424 Jps
30248 JobHistoryServer
29067 DataNode
29933 NodeManager
29261 SecondaryNameNode
通过Web界面查看任务的运行情况
关闭YARN和Hadoop的脚本如下：
hadoop@dblab:/usr/local/hadoop$ ./sbin/stop-yarn.sh
stopping yarn daemons
stopping resourcemanager
localhost: stopping nodemanager
no proxyserver to stop
hadoop@dblab:/usr/local/hadoop$ ./sbin/mr-jobhistory-daemon.sh stop historyserver
stopping historyserver
hadoop@dblab:/usr/local/hadoop$ ./sbin/stop-dfs.sh
Stopping namenodes on [localhost]
localhost: stopping namenode
localhost: stopping datanode
Stopping secondary namenodes [0.0.0.0]
0.0.0.0: stopping secondarynamenode