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开发环境:Win7(64bit)+Eclipse(kepler service release 2)
配置环境:Ubuntu Server 14.04.1 LTS(64-bit only)
辅助工具:WinSCP + Putty
Hadoop版本:2.5.0
Hadoop的Eclipse开发插件(2.x版本适用):http://pan.baidu.com/s/1eQy49sm
服务器端JDK版本:OpenJDK7.0
以上所有工具请自行下载安装。
最近一直在摸索Hadoop2的配置,因为Hadoop2对原有的一些框架API做了调整,但也还是兼容旧版本的(包括配置)。像我这种就喜欢用新的东西的人,当然要尝一下鲜了,现在网上比较少新版本的配置教程,那么下面我就来分享一下我自己的实战经验,如有不正确的地欢迎指正:)。
假设我们已经成功地安装了Ubuntu Server、OpenJDK、SSH,如果还没有安装的话请先安装,自己网上找一下教程,这里我就说一下SSH的无口令登陆设置。首先通过
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$ ssh localhost
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测试一下自己有没有设置好无口令登陆,如果没有设置好,系统将要求你输入密码,通过下面的设置可以实现无口令登陆,具体原理请百度谷歌:
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$ ssh-keygen -t dsa -P
''
-f ~/.ssh/id_dsa
$ cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys
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其次是Hadoop安装(假设已经安装好OpenJDK以及配置好了环境变量),到Hadoop官网下载一个Hadoop2.5.0版本的下来,好像大概有100多M的tar.gz包,下载 下来后自行解压,我的是放在/usr/mywind下面,Hadoop主目录完整路径是/usr/mywind/hadoop,这个路径根据你个人喜好放吧。
解压完后,打开hadoop主目录下的etc/hadoop/hadoop-env.sh文件,在最后面加入下面内容:
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# set to the root of your Java installation
export JAVA_HOME=/usr/lib/jvm/java-
7
-openjdk-amd64
# Assuming your installation directory is /usr/mywind/hadoop
export HADOOP_PREFIX=/usr/mywind/hadoop
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为了方便起见,我建设把Hadoop的bin目录及sbin目录也加入到环境变量中,我是直接修改了Ubuntu的/etc/environment文件,内容如下:
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PATH=
"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/jvm/java-7-openjdk-amd64/bin:/usr/mywind/hadoop/bin:/usr/mywind/hadoop/sbin"
JAVA_HOME=
"/usr/lib/jvm/java-7-openjdk-amd64"
CLASSPATH=
".:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar"
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也可以通过修改profile来完成这个设置,看个人习惯咯。假如上面的设置你都完成了,可以在命令行里面测试一下Hadoop命令,如下图:
假如你能看到上面的结果,恭喜你,Hadoop安装完成了。接下来我们可以进行伪分布配置(Hadoop可以在伪分布模式下运行单结点)。
接下来我们要配置的文件有四个,分别是/usr/mywind/hadoop/etc/hadoop目录下的yarn-site.xml、mapred-site.xml、hdfs-site.xml、core-site.xml(注意:这个版本下默认没有yarn-site.xml文件,但有个yarn-site.xml.properties文件,把后缀修改成前者即可),关于yarn新特性可以参考官网或者这个文章http://www.ibm.com/developerworks/cn/opensource/os-cn-hadoop-yarn/。
首先是core-site.xml配置HDFS地址及临时目录(默认的临时目录在重启后会删除):
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<
configuration
>
<
property
>
<
name
>fs.defaultFS</
name
>
<
value
>hdfs://192.168.8.184:9000</
value
>
<
description
>same as fs.default.name</
description
>
</
property
>
<
property
>
<
name
>hadoop.tmp.dir</
name
>
<
value
>/usr/mywind/tmp</
value
>
<
description
>A base for other temporary directories.</
description
>
</
property
>
</
configuration
>
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然后是hdfs-site.xml配置集群数量及其他一些可选配置比如NameNode目录、DataNode目录等等:
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<
configuration
>
<
property
>
<
name
>dfs.namenode.name.dir</
name
>
<
value
>/usr/mywind/name</
value
>
<
description
>same as dfs.name.dir</
description
>
</
property
>
<
property
>
<
name
>dfs.datanode.data.dir</
name
>
<
value
>/usr/mywind/data</
value
>
<
description
>same as dfs.data.dir</
description
>
</
property
>
<
property
>
<
name
>dfs.replication</
name
>
<
value
>1</
value
>
<
description
>same as old frame,recommend set the value as the cluster DataNode host numbers!</
description
>
</
property
>
</
configuration
>
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接着是mapred-site.xml配置启用yarn框架:
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<
configuration
>
<
property
>
<
name
>mapreduce.framework.name</
name
>
<
value
>yarn</
value
>
</
property
>
</
configuration
>
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最后是yarn-site.xml配置NodeManager:
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<
configuration
>
<!-- Site specific YARN configuration properties -->
<
property
>
<
name
>yarn.nodemanager.aux-services</
name
>
<
value
>mapreduce_shuffle</
value
>
</
property
>
</
configuration
>
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注意,网上的旧版本教程可能会把value写成mapreduce.shuffle,这个要特别注意一下的,至此我们所有的文件配置都已经完成了,下面进行HDFS文件系统进行格式化:
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$ hdfs namenode -format
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然后启用NameNode及DataNode进程:
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$ start-yarn.sh
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然后创建hdfs文件目录
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$ hdfs dfs -mkdir /user
$ hdfs dfs -mkdir /user/a01513
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注意,这个a01513是我在Ubuntu上的用户名,最好保持与系统用户名一致,据说不一致会有许多权限等问题,我之前试过改成其他名字,报错,实在麻烦就改成跟系统用户名一致吧。
然后把要测试的输入文件放在文件系统中:
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$ hdfs dfs -put /usr/mywind/psa input
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文件内容是Hadoop经典的天气例子的数据:
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12345679867623119010123456798676231190101234567986762311901012345679867623119010123456
+
001212345678903456
12345679867623119010123456798676231190101234567986762311901012345679867623119010123456
+
011212345678903456
12345679867623119010123456798676231190101234567986762311901012345679867623119010123456
+
021212345678903456
12345679867623119010123456798676231190101234567986762311901012345679867623119010123456
+
003212345678903456
12345679867623119010123456798676231190201234567986762311901012345679867623119010123456
+
004212345678903456
12345679867623119010123456798676231190201234567986762311901012345679867623119010123456
+
010212345678903456
12345679867623119010123456798676231190201234567986762311901012345679867623119010123456
+
011212345678903456
12345679867623119010123456798676231190501234567986762311901012345679867623119010123456
+
041212345678903456
12345679867623119010123456798676231190501234567986762311901012345679867623119010123456
+
008212345678903456
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把文件拷贝到HDFS目录之后,我们可以通过浏览器查看相关的文件及一些状态:
http://192.168.8.184:50070/
这里的IP地址根据你实际的Hadoop服务器地址啦。
好吧,我们所有的Hadoop后台服务搭建跟数据准备都已经完成了,那么我们的M/R程序也要开始动手写了,不过在写当然先配置开发环境了。
关于JDK及ECLIPSE的安装我就不再介绍了,相信能玩Hadoop的人对这种配置都已经再熟悉不过了,如果实在不懂建议到谷歌百度去搜索一下教程。假设你已经把Hadoop的Eclipse插件下载下来了,然后解压把jar文件放到Eclipse的plugins文件夹里面:
重启Eclipse即可。
然后我们再安装Hadoop到Win7下,在这不再详细说明,跟安装JDK大同小异,在这个例子中我安装到了E:\hadoop。
启动Eclipse,点击菜单栏的【Windows/窗口】→【Preferences/首选项】→【Hadoop Map/Reduce】,把Hadoop Installation Directory设置成开发机上的Hadoop主目录:
点击OK。
开发环境配置完成,下面我们可以新建一个测试Hadoop项目,右键【NEW/新建】→【Others、其他】,选择Map/Reduce Project
输入项目名称点击【Finish/完成】:
创建完成后可以看到如下目录:
然后在SRC下建立下面包及类:
以下是代码内容:
TestMapper.java
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package
com.my.hadoop.mapper;
import
java.io.IOException;
import
org.apache.commons.logging.Log;
import
org.apache.commons.logging.LogFactory;
import
org.apache.hadoop.io.IntWritable;
import
org.apache.hadoop.io.LongWritable;
import
org.apache.hadoop.io.Text;
import
org.apache.hadoop.mapred.MapReduceBase;
import
org.apache.hadoop.mapred.Mapper;
import
org.apache.hadoop.mapred.OutputCollector;
import
org.apache.hadoop.mapred.Reporter;
public
class
TestMapper
extends
MapReduceBase
implements
Mapper<LongWritable, Text, Text, IntWritable> {
private
static
final
int
MISSING =
9999
;
private
static
final
Log LOG = LogFactory.getLog(TestMapper.
class
);
public
void
map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output,Reporter reporter)
throws
IOException {
String line = value.toString();
String year = line.substring(
15
,
19
);
int
airTemperature;
if
(line.charAt(
87
) ==
'+'
) {
// parseInt doesn't like leading plus signs
airTemperature = Integer.parseInt(line.substring(
88
,
92
));
}
else
{
airTemperature = Integer.parseInt(line.substring(
87
,
92
));
}
LOG.info(
"loki:"
+airTemperature);
String quality = line.substring(
92
,
93
);
LOG.info(
"loki2:"
+quality);
if
(airTemperature != MISSING && quality.matches(
"[012459]"
)) {
LOG.info(
"loki3:"
+quality);
output.collect(
new
Text(year),
new
IntWritable(airTemperature));
}
}
}
|
TestReducer.java
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package
com.my.hadoop.reducer;
import
java.io.IOException;
import
java.util.Iterator;
import
org.apache.hadoop.io.IntWritable;
import
org.apache.hadoop.io.Text;
import
org.apache.hadoop.mapred.MapReduceBase;
import
org.apache.hadoop.mapred.OutputCollector;
import
org.apache.hadoop.mapred.Reporter;
import
org.apache.hadoop.mapred.Reducer;
public
class
TestReducer
extends
MapReduceBase
implements
Reducer<Text, IntWritable, Text, IntWritable> {
@Override
public
void
reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output,Reporter reporter)
throws
IOException{
int
maxValue = Integer.MIN_VALUE;
while
(values.hasNext()) {
maxValue = Math.max(maxValue, values.next().get());
}
output.collect(key,
new
IntWritable(maxValue));
}
}
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TestHadoop.java
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package
com.my.hadoop.test.main;
import
org.apache.hadoop.fs.Path;
import
org.apache.hadoop.io.IntWritable;
import
org.apache.hadoop.io.Text;
import
org.apache.hadoop.mapred.FileInputFormat;
import
org.apache.hadoop.mapred.FileOutputFormat;
import
org.apache.hadoop.mapred.JobClient;
import
org.apache.hadoop.mapred.JobConf;
import
com.my.hadoop.mapper.TestMapper;
import
com.my.hadoop.reducer.TestReducer;
public
class
TestHadoop {
public
static
void
main(String[] args)
throws
Exception{
if
(args.length !=
2
) {
System.err
.println(
"Usage: MaxTemperature <input path> <output path>"
);
System.exit(-
1
);
}
JobConf job =
new
JobConf(TestHadoop.
class
);
job.setJobName(
"Max temperature"
);
FileInputFormat.addInputPath(job,
new
Path(args[
0
]));
FileOutputFormat.setOutputPath(job,
new
Path(args[
1
]));
job.setMapperClass(TestMapper.
class
);
job.setReducerClass(TestReducer.
class
);
job.setOutputKeyClass(Text.
class
);
job.setOutputValueClass(IntWritable.
class
);
JobClient.runJob(job);
}
}
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为了方便对于Hadoop的HDFS文件系统操作,我们可以在Eclipse下面的Map/Reduce Locations窗口与Hadoop建立连接,直接右键新建Hadoop连接即可:
连接配置如下:
然后点击完成即可,新建完成后,我们可以在左侧目录中看到HDFS的文件系统目录:
这里不仅可以显示目录结构,还可以对文件及目录进行删除、新增等操作,非常方便。
当上面的工作都做好之后,就可以把这个项目导出来了(导成jar文件放到Hadoop服务器上运行):
点击完成,然后把这个testt.jar文件上传到Hadoop服务器(192.168.8.184)上,目录(其实可以放到其他目录,你自己喜欢)是:
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/usr/mywind/hadoop/share/hadoop/mapreduce
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如下图:
当上面的工作准备好了之后,我们运行自己写的Hadoop程序很简单:
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$ hadoop jar /usr/mywind/hadoop/share/hadoop/mapreduce/testt.jar com.my.hadoop.test.main.TestHadoop input output
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注意这是output文件夹名称不能重复哦,假如你执行了一次,在HDFS文件系统下面会自动生成一个output文件夹,第二次运行时,要么把output文件夹先删除($ hdfs dfs -rmr /user/a01513/output),要么把命令中的output改成其他名称如output1、output2等等。
如果看到以下输出结果,证明你的运行成功了:
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a01513@hadoop :~$ hadoop jar
/usr/mywind/hadoop/share/hadoop/mapreduce/testt
.jar com.my.hadoop.
test
.main.TestHadoop input output
14
/09/02
11:14:03 INFO client.RMProxy: Connecting to ResourceManager at
/0
.0.0.0 :8032
14
/09/02
11:14:04 INFO client.RMProxy: Connecting to ResourceManager at
/0
.0.0.0 :8032
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/09/02
11:14:04 WARN mapreduce.JobSubmitter: Hadoop
command
-line option parsin g not performed. Implement the Tool interface and execute your application with ToolRunner to remedy this.
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/09/02
11:14:04 INFO mapred.FileInputFormat: Total input paths to process : 1
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/09/02
11:14:04 INFO mapreduce.JobSubmitter: number of splits:2
14
/09/02
11:14:05 INFO mapreduce.JobSubmitter: Submitting tokens
for
job: job_14 09386620927_0015
14
/09/02
11:14:05 INFO impl.YarnClientImpl: Submitted application application_14 09386620927_0015
14
/09/02
11:14:05 INFO mapreduce.Job: The url to track the job: http:
//hadoop
:80 88
/proxy/application_1409386620927_0015/
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/09/02
11:14:05 INFO mapreduce.Job: Running job: job_1409386620927_0015
14
/09/02
11:14:12 INFO mapreduce.Job: Job job_1409386620927_0015 running
in
uber mode :
false
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/09/02
11:14:12 INFO mapreduce.Job: map 0% reduce 0%
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11:14:21 INFO mapreduce.Job: map 100% reduce 0%
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11:14:28 INFO mapreduce.Job: map 100% reduce 100%
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/09/02
11:14:28 INFO mapreduce.Job: Job job_1409386620927_0015 completed successfully
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/09/02
11:14:29 INFO mapreduce.Job: Counters: 49
File System Counters
FILE: Number of bytes
read
=105
FILE: Number of bytes written=289816
FILE: Number of
read
operations=0
FILE: Number of large
read
operations=0
FILE: Number of write operations=0
HDFS: Number of bytes
read
=1638
HDFS: Number of bytes written=10
HDFS: Number of
read
operations=9
HDFS: Number of large
read
operations=0
HDFS: Number of write operations=2
Job Counters
Launched map tasks=2
Launched reduce tasks=1
Data-
local
map tasks=2
Total
time
spent by all maps
in
occupied slots (ms)=14817
Total
time
spent by all reduces
in
occupied slots (ms)=4500
Total
time
spent by all map tasks (ms)=14817
Total
time
spent by all reduce tasks (ms)=4500
Total vcore-seconds taken by all map tasks=14817
Total vcore-seconds taken by all reduce tasks=4500
Total megabyte-seconds taken by all map tasks=15172608
Total megabyte-seconds taken by all reduce tasks=4608000
Map-Reduce Framework
Map input records=9
Map output records=9
Map output bytes=81
Map output materialized bytes=111
Input
split
bytes=208
Combine input records=0
Combine output records=0
Reduce input
groups
=1
Reduce shuffle bytes=111
Reduce input records=9
Reduce output records=1
Spilled Records=18
Shuffled Maps =2
Failed Shuffles=0
Merged Map outputs=2
GC
time
elapsed (ms)=115
CPU
time
spent (ms)=1990
Physical memory (bytes) snapshot=655314944
Virtual memory (bytes) snapshot=2480295936
Total committed heap usage (bytes)=466616320
Shuffle Errors
BAD_ID=0
CONNECTION=0
IO_ERROR=0
WRONG_LENGTH=0
WRONG_MAP=0
WRONG_REDUCE=0
File Input Format Counters
Bytes Read=1430
File Output Format Counters
Bytes Written=10
a01513@hadoop :~$
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我们可以到Eclipse查看输出的结果:
或者用命令行查看:
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$ hdfs dfs -
cat
output
/part-00000
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假如你们发现运行后结果是为空的,可能到日志目录查找相应的log.info输出信息,log目录在:/usr/mywind/hadoop/logs/userlogs 下面。
好了,不太喜欢打字,以上就是整个过程了,欢迎大家来学习指正。
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