Hadoop集群简单入门
Hadoop集群搭建
自己配置Hadoop的话太过复杂了，因为自己着急学习，就使用了黑马的快照。如果小伙伴们也想的话可以直接看黑马的课程，快照的话关注黑马程序员公众号，输入Hadoop就能获取资料，到时候直接看课程P9就可以了。
Hadoop集群启停命令和Web UI
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手动逐个启停
优点：准确的启动或关闭进程，避免群起群停。 缺点：多个进程同时操作麻烦 -
shell脚本一键启停
前提：配置好SSH免密登录和workers文件。 HDFS集群：start-dfs.sh/stop-dfs.sh YARN集群：start-yarn.sh/stop-yarn.sh Hadoop集群:start-all.sh/start-all.sh -
启停结果查看
1. jps命令查看进程 2. 或者在下载路径下logs文件查看
启动结果：
node1：
node2：
4. Web UI
HDFS Web界面：NameNode所在机器，端口是9870
YARN Web界面：ResourceManager所在机器，端口号是8088
结果如下：
HDFS:
其中在这个界面，我们主要是浏览文件系统，即下图：
YARN:
HDFS初体验
[root@node1 ~]# hadoop fs -ls /
Found 3 items
drwxr-xr-x - root supergroup 0 2021-10-26 15:04 /itcast
drwx------ - root supergroup 0 2021-10-26 15:20 /tmp
drwxr-xr-x - root supergroup 0 2021-10-26 15:23 /user
[root@node1 ~]# hadoop fs -mkdir itcast
[root@node1 ~]# hadoop fs -ls /
Found 3 items
drwxr-xr-x - root supergroup 0 2021-10-26 15:04 /itcast
drwx------ - root supergroup 0 2021-10-26 15:20 /tmp
drwxr-xr-x - root supergroup 0 2021-10-26 15:23 /user
[root@node1 ~]# hadoop fs -put anaconda-ks.cfg /itcast
[root@node1 ~]# echo 1 > 1.txt
[root@node1 ~]# ll
总用量 32
-rw-r--r-- 1 root root 2 10月 24 21:15 1.txt
-rw-------. 1 root root 1340 9月 11 2020 anaconda-ks.cfg
drwxr-xr-x 2 root root 55 10月 5 00:08 hivedata
-rw------- 1 root root 23341 10月 5 00:11 nohup.out
[root@node1 ~]# hadoop fs -put 1.txt /
运行结果：
MapReduce+YARN初体验
[root@node1 ~]# cd /export/server/hadoop-3.3.0/
[root@node1 hadoop-3.3.0]# ll
总用量 88
drwxr-xr-x 2 root root 203 7月 15 2021 bin
drwxr-xr-x 3 root root 20 7月 15 2021 etc
drwxr-xr-x 2 root root 106 7月 15 2021 include
drwxr-xr-x 3 root root 20 7月 15 2021 lib
drwxr-xr-x 4 root root 288 7月 15 2021 libexec
-rw-rw-r-- 1 root root 22976 7月 5 2020 LICENSE-binary
drwxr-xr-x 2 root root 4096 7月 15 2021 licenses-binary
-rw-rw-r-- 1 root users 15697 3月 25 2020 LICENSE.txt
drwxr-xr-x 3 root root 4096 10月 24 20:33 logs
-rw-rw-r-- 1 root users 27570 3月 25 2020 NOTICE-binary
-rw-rw-r-- 1 root users 1541 3月 25 2020 NOTICE.txt
-rw-rw-r-- 1 root users 175 3月 25 2020 README.txt
drwxr-xr-x 3 root root 4096 7月 15 2021 sbin
drwxr-xr-x 3 root root 20 7月 15 2021 share
[root@node1 hadoop-3.3.0]# cd share/hadoop/
[root@node1 hadoop]# ll
总用量 12
drwxr-xr-x 2 root root 123 7月 15 2021 client
drwxr-xr-x 6 root root 217 7月 15 2021 common
drwxr-xr-x 6 root root 4096 7月 15 2021 hdfs
drwxr-xr-x 5 root root 4096 7月 15 2021 mapreduce
drwxr-xr-x 7 root root 87 7月 15 2021 tools
drwxr-xr-x 8 root root 4096 7月 15 2021 yarn
[root@node1 hadoop]# cd mapreduce/
[root@node1 mapreduce]# ll
总用量 5276
-rw-r--r-- 1 root root 589704 7月 15 2021 hadoop-mapreduce-client-app-3.3.0.jar
-rw-r--r-- 1 root root 803842 7月 15 2021 hadoop-mapreduce-client-common-3.3.0.jar
-rw-r--r-- 1 root root 1623803 7月 15 2021 hadoop-mapreduce-client-core-3.3.0.jar
-rw-r--r-- 1 root root 181995 7月 15 2021 hadoop-mapreduce-client-hs-3.3.0.jar
-rw-r--r-- 1 root root 10323 7月 15 2021 hadoop-mapreduce-client-hs-plugins-3.3.0.jar
-rw-r--r-- 1 root root 50701 7月 15 2021 hadoop-mapreduce-client-jobclient-3.3.0.jar
-rw-r--r-- 1 root root 1651503 7月 15 2021 hadoop-mapreduce-client-jobclient-3.3.0-tests.jar
-rw-r--r-- 1 root root 91017 7月 15 2021 hadoop-mapreduce-client-nativetask-3.3.0.jar
-rw-r--r-- 1 root root 62310 7月 15 2021 hadoop-mapreduce-client-shuffle-3.3.0.jar
-rw-r--r-- 1 root root 22637 7月 15 2021 hadoop-mapreduce-client-uploader-3.3.0.jar
-rw-r--r-- 1 root root 281197 7月 15 2021 hadoop-mapreduce-examples-3.3.0.jar
drwxr-xr-x 2 root root 4096 7月 15 2021 jdiff
drwxr-xr-x 2 root root 30 7月 15 2021 lib-examples
drwxr-xr-x 2 root root 4096 7月 15 2021 sources
[root@node1 mapreduce]# hadoop jar hadoop-mapreduce-examples-3.3.0.jar pi 2 2
Number of Maps = 2
Samples per Map = 2
Wrote input for Map #0
Wrote input for Map #1
Starting Job
2022-10-24 21:26:25,174 INFO client.DefaultNoHARMFailoverProxyProvider: Connecting to ResourceManager at node1/192.168.88.151:8032
2022-10-24 21:26:25,982 INFO mapreduce.JobResourceUploader: Disabling Erasure Coding for path: /tmp/hadoop-yarn/staging/root/.staging/job_1666614796978_0001
2022-10-24 21:26:26,237 INFO input.FileInputFormat: Total input files to process : 2
2022-10-24 21:26:26,308 INFO mapreduce.JobSubmitter: number of splits:2
2022-10-24 21:26:26,492 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1666614796978_0001
2022-10-24 21:26:26,492 INFO mapreduce.JobSubmitter: Executing with tokens: []
2022-10-24 21:26:26,687 INFO conf.Configuration: resource-types.xml not found
2022-10-24 21:26:26,688 INFO resource.ResourceUtils: Unable to find 'resource-types.xml'.
2022-10-24 21:26:27,169 INFO impl.YarnClientImpl: Submitted application application_1666614796978_0001
2022-10-24 21:26:27,218 INFO mapreduce.Job: The url to track the job: //node1:8088/proxy/application_1666614796978_0001/
2022-10-24 21:26:27,219 INFO mapreduce.Job: Running job: job_1666614796978_0001
2022-10-24 21:26:38,491 INFO mapreduce.Job: Job job_1666614796978_0001 running in uber mode : false
2022-10-24 21:26:38,492 INFO mapreduce.Job: map 0% reduce 0%
2022-10-24 21:26:48,699 INFO mapreduce.Job: map 100% reduce 0%
2022-10-24 21:26:56,768 INFO mapreduce.Job: map 100% reduce 100%
2022-10-24 21:26:56,777 INFO mapreduce.Job: Job job_1666614796978_0001 completed successfully
2022-10-24 21:26:56,877 INFO mapreduce.Job: Counters: 54
File System Counters
FILE: Number of bytes read=50
FILE: Number of bytes written=795057
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=520
HDFS: Number of bytes written=215
HDFS: Number of read operations=13
HDFS: Number of large read operations=0
HDFS: Number of write operations=3
HDFS: Number of bytes read erasure-coded=0
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)=13640
Total time spent by all reduces in occupied slots (ms)=5089
Total time spent by all map tasks (ms)=13640
Total time spent by all reduce tasks (ms)=5089
Total vcore-milliseconds taken by all map tasks=13640
Total vcore-milliseconds taken by all reduce tasks=5089
Total megabyte-milliseconds taken by all map tasks=13967360
Total megabyte-milliseconds taken by all reduce tasks=5211136
Map-Reduce Framework
Map input records=2
Map output records=4
Map output bytes=36
Map output materialized bytes=56
Input split bytes=284
Combine input records=0
Combine output records=0
Reduce input groups=2
Reduce shuffle bytes=56
Reduce input records=4
Reduce output records=0
Spilled Records=8
Shuffled Maps =2
Failed Shuffles=0
Merged Map outputs=2
GC time elapsed (ms)=906
CPU time spent (ms)=5000
Physical memory (bytes) snapshot=793993216
Virtual memory (bytes) snapshot=8363589632
Total committed heap usage (bytes)=677380096
Peak Map Physical memory (bytes)=299003904
Peak Map Virtual memory (bytes)=2789269504
Peak Reduce Physical memory (bytes)=200515584
Peak Reduce Virtual memory (bytes)=2788036608
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=236
File Output Format Counters
Bytes Written=97
Job Finished in 31.796 seconds
Estimated value of Pi is 4.00000000000000000000
运行结果：
