背景
2017.12.13日Apache Hadoop 3.0.0正式版本发布，默认支持阿里云OSS对象存储系统，作为Hadoop兼容的文件系统，后续版本号大于等于Hadoop 2.9.x系列也支持OSS。然而，低版本的Apache Hadoop官方不再支持OSS，本文将描述如何通过支持包来使Hadoop 2.7.2能够读写OSS。
如何使用
下面的步骤需要在所有的Hadoop节点执行
下载支持包
http://gosspublic.alicdn.com/hadoop-spark/hadoop-oss-2.7.2.tar.gz
解压这个支持包，里面的文件是：
[root@apache hadoop-oss-2.7.2]# ls -lh
总用量 3.1M
-rw-r--r-- 1 root root 3.1M 2月 28 17:01 hadoop-aliyun-2.7.2.jar这个支持包是根据Hadoop 2.7.2的版本，并打了Apache Hadoop对OSS支持的patch后编译得到，其他的小版本对OSS的支持后续也将陆续提供。
部署
首先将文件hadoop-aliyun-2.7.2.jar复制到$HADOOP_HOME/share/hadoop/tools/lib/目录下；
修改$HADOOP_HOME/libexec/hadoop-config.sh文件，在文件的327行加下代码：
CLASSPATH=$CLASSPATH:$TOOL_PATH修改的目的就是将$HADOOP_HOME/share/hadoop/tools/lib/放到Hadoop的CLASSPATH里面；下面是修改前后，这个文件的diff供参考(hadoop-config.sh.bak是修改前的文件):
[root@apache hadoop-2.7.2]# diff -C 3 libexec/hadoop-config.sh.bak libexec/hadoop-config.sh
*** libexec/hadoop-config.sh.bak 2019-03-01 10:35:59.629136885 +0800
--- libexec/hadoop-config.sh 2019-02-28 16:33:39.661707800 +0800
***************
*** 325,330 ****
--- 325,332 ----
CLASSPATH=${CLASSPATH}:$HADOOP_MAPRED_HOME/$MAPRED_DIR'/*'
fi
+ CLASSPATH=$CLASSPATH:$TOOL_PATH
+
# Add the user-specified CLASSPATH via HADOOP_CLASSPATH
# Add it first or last depending on if user has
# set env-var HADOOP_USER_CLASSPATH_FIRST增加OSS的配置
修改core-site.xml文件，增加如下配置项：
| 配置项 | 值 | 说明 |
|---|---|---|
| fs.oss.endpoint | 如 oss-cn-zhangjiakou-internal.aliyuncs.com | 要连接的endpoint |
| fs.oss.accessKeyId | access key id | |
| fs.oss.accessKeySecret | access key secret | |
| fs.oss.impl | org.apache.hadoop.fs.aliyun.oss.AliyunOSSFileSystem | hadoop oss文件系统实现类，目前固定为这个 |
| fs.oss.buffer.dir | /tmp/oss | 临时文件目录 |
| fs.oss.connection.secure.enabled | false | 是否enable https, 根据需要来设置，enable https会影响性能 |
| fs.oss.connection.maximum | 2048 | 与oss的连接数，根据需要设置 |
相关参数的解释可以在这里找到
重启集群，验证读写OSS
增加配置后，重启集群，重启后，可以测试
# 测试写
hadoop fs -mkdir oss://{your-bucket-name}/hadoop-test
# 测试读
hadoop fs -ls oss://{your-bucket-name}/运行teragen
[root@apache hadoop-2.7.2]# hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.2.jar teragen -Dmapred.map.tasks=100 10995116 oss://{your-bucket-name}/1G-input
19/02/28 16:38:59 INFO client.RMProxy: Connecting to ResourceManager at apache/192.168.0.176:8032
19/02/28 16:39:01 INFO terasort.TeraSort: Generating 10995116 using 100
19/02/28 16:39:01 INFO mapreduce.JobSubmitter: number of splits:100
19/02/28 16:39:01 INFO Configuration.deprecation: mapred.map.tasks is deprecated. Instead, use mapreduce.job.maps
19/02/28 16:39:01 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1551343125387_0001
19/02/28 16:39:02 INFO impl.YarnClientImpl: Submitted application application_1551343125387_0001
19/02/28 16:39:02 INFO mapreduce.Job: The url to track the job: http://apache:8088/proxy/application_1551343125387_0001/
19/02/28 16:39:02 INFO mapreduce.Job: Running job: job_1551343125387_0001
19/02/28 16:39:09 INFO mapreduce.Job: Job job_1551343125387_0001 running in uber mode : false
19/02/28 16:39:09 INFO mapreduce.Job: map 0% reduce 0%
19/02/28 16:39:18 INFO mapreduce.Job: map 1% reduce 0%
19/02/28 16:39:19 INFO mapreduce.Job: map 2% reduce 0%
19/02/28 16:39:21 INFO mapreduce.Job: map 4% reduce 0%
19/02/28 16:39:25 INFO mapreduce.Job: map 5% reduce 0%
19/02/28 16:39:28 INFO mapreduce.Job: map 6% reduce 0%
......
19/02/28 16:42:36 INFO mapreduce.Job: map 94% reduce 0%
19/02/28 16:42:38 INFO mapreduce.Job: map 95% reduce 0%
19/02/28 16:42:41 INFO mapreduce.Job: map 96% reduce 0%
19/02/28 16:42:44 INFO mapreduce.Job: map 97% reduce 0%
19/02/28 16:42:45 INFO mapreduce.Job: map 98% reduce 0%
19/02/28 16:42:46 INFO mapreduce.Job: map 99% reduce 0%
19/02/28 16:42:48 INFO mapreduce.Job: map 100% reduce 0%
19/02/28 16:43:11 INFO mapreduce.Job: Job job_1551343125387_0001 completed successfully
19/02/28 16:43:12 INFO mapreduce.Job: Counters: 37
File System Counters
FILE: Number of bytes read=0
FILE: Number of bytes written=11931190
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=8497
HDFS: Number of bytes written=0
HDFS: Number of read operations=100
HDFS: Number of large read operations=0
HDFS: Number of write operations=0
OSS: Number of bytes read=0
OSS: Number of bytes written=1099511600
OSS: Number of read operations=1100
OSS: Number of large read operations=0
OSS: Number of write operations=500
......运行distcp
从OSS往HDFS拷贝数据
[root@apache hadoop-2.7.2]# hadoop distcp oss://{your-bucket-name}/data hdfs:/data/input
19/03/05 09:43:59 INFO tools.DistCp: Input Options: DistCpOptions{atomicCommit=false, syncFolder=false, deleteMissing=false, ignoreFailures=false, maxMaps=20, sslConfigurationFile='null', copyStrategy='uniformsize', sourceFileListing=null, sourcePaths=[oss://{your-bucket-name}/data], targetPath=hdfs:/data/input, targetPathExists=false, preserveRawXattrs=false}
19/03/05 09:43:59 INFO client.RMProxy: Connecting to ResourceManager at apache/192.168.0.176:8032
19/03/05 09:44:00 INFO Configuration.deprecation: io.sort.mb is deprecated. Instead, use mapreduce.task.io.sort.mb
19/03/05 09:44:00 INFO Configuration.deprecation: io.sort.factor is deprecated. Instead, use mapreduce.task.io.sort.factor
19/03/05 09:44:01 INFO client.RMProxy: Connecting to ResourceManager at apache/192.168.0.176:8032
19/03/05 09:44:01 INFO mapreduce.JobSubmitter: number of splits:24
19/03/05 09:44:01 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1551343125387_0008
19/03/05 09:44:01 INFO impl.YarnClientImpl: Submitted application application_1551343125387_0008
19/03/05 09:44:01 INFO mapreduce.Job: The url to track the job: http://apache:8088/proxy/application_1551343125387_0008/
19/03/05 09:44:01 INFO tools.DistCp: DistCp job-id: job_1551343125387_0008
19/03/05 09:44:01 INFO mapreduce.Job: Running job: job_1551343125387_0008
19/03/05 09:44:07 INFO mapreduce.Job: Job job_1551343125387_0008 running in uber mode : false
19/03/05 09:44:07 INFO mapreduce.Job: map 0% reduce 0%
19/03/05 09:44:16 INFO mapreduce.Job: map 4% reduce 0%
19/03/05 09:44:19 INFO mapreduce.Job: map 8% reduce 0%
......
19/03/05 09:45:11 INFO mapreduce.Job: map 96% reduce 0%
19/03/05 09:45:12 INFO mapreduce.Job: map 100% reduce 0%
19/03/05 09:45:13 INFO mapreduce.Job: Job job_1551343125387_0008 completed successfully
19/03/05 09:45:13 INFO mapreduce.Job: Counters: 38
File System Counters
FILE: Number of bytes read=0
FILE: Number of bytes written=2932262
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=24152
HDFS: Number of bytes written=1099511600
HDFS: Number of read operations=898
HDFS: Number of large read operations=0
HDFS: Number of write operations=251
OSS: Number of bytes read=1099511600
OSS: Number of bytes written=0
OSS: Number of read operations=2404
OSS: Number of large read operations=0
OSS: Number of write operations=0
......
[root@apache hadoop-2.7.2]# hadoop fs -ls hdfs:/data
Found 1 items
drwxr-xr-x - root supergroup 0 2019-03-05 09:45 hdfs:///data/input从HDFS往OSS拷贝数据
[root@apache hadoop-2.7.2]# hadoop distcp hdfs:/data/input oss://{your-bucket-name}/data/output
19/03/05 09:48:06 INFO tools.DistCp: Input Options: DistCpOptions{atomicCommit=false, syncFolder=false, deleteMissing=false, ignoreFailures=false, maxMaps=20, sslConfigurationFile='null', copyStrategy='uniformsize', sourceFileListing=null, sourcePaths=[hdfs:/data/input], targetPath=oss://{your-bucket-name}/data/output, targetPathExists=false, preserveRawXattrs=false}
19/03/05 09:48:06 INFO client.RMProxy: Connecting to ResourceManager at apache/192.168.0.176:8032
19/03/05 09:48:06 INFO Configuration.deprecation: io.sort.mb is deprecated. Instead, use mapreduce.task.io.sort.mb
19/03/05 09:48:06 INFO Configuration.deprecation: io.sort.factor is deprecated. Instead, use mapreduce.task.io.sort.factor
19/03/05 09:48:07 INFO client.RMProxy: Connecting to ResourceManager at apache/192.168.0.176:8032
19/03/05 09:48:07 INFO mapreduce.JobSubmitter: number of splits:24
19/03/05 09:48:08 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1551343125387_0009
19/03/05 09:48:08 INFO impl.YarnClientImpl: Submitted application application_1551343125387_0009
19/03/05 09:48:08 INFO mapreduce.Job: The url to track the job: http://apache:8088/proxy/application_1551343125387_0009/
19/03/05 09:48:08 INFO tools.DistCp: DistCp job-id: job_1551343125387_0009
19/03/05 09:48:08 INFO mapreduce.Job: Running job: job_1551343125387_0009
19/03/05 09:48:14 INFO mapreduce.Job: Job job_1551343125387_0009 running in uber mode : false
19/03/05 09:48:14 INFO mapreduce.Job: map 0% reduce 0%
19/03/05 09:48:24 INFO mapreduce.Job: map 4% reduce 0%
19/03/05 09:48:27 INFO mapreduce.Job: map 8% reduce 0%
......
19/03/05 09:49:18 INFO mapreduce.Job: map 92% reduce 0%
19/03/05 09:49:20 INFO mapreduce.Job: map 96% reduce 0%
19/03/05 09:49:21 INFO mapreduce.Job: map 100% reduce 0%
19/03/05 09:49:22 INFO mapreduce.Job: Job job_1551343125387_0009 completed successfully
19/03/05 09:49:22 INFO mapreduce.Job: Counters: 38
File System Counters
FILE: Number of bytes read=0
FILE: Number of bytes written=2932910
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=1099535478
HDFS: Number of bytes written=0
HDFS: Number of read operations=548
HDFS: Number of large read operations=0
HDFS: Number of write operations=48
OSS: Number of bytes read=0
OSS: Number of bytes written=1099511600
OSS: Number of read operations=1262
OSS: Number of large read operations=0
OSS: Number of write operations=405
......
[root@apache hadoop-2.7.2]# hadoop fs -ls oss://{your-bucket-name}/data/output
Found 101 items
-rw-rw-rw- 1 root root 0 2019-03-05 09:48 oss://{your-bucket-name}/data/output/_SUCCESS
-rw-rw-rw- 1 root root 10995200 2019-03-05 09:48 oss://{your-bucket-name}/data/output/part-m-00000
-rw-rw-rw- 1 root root 10995100 2019-03-05 09:48 oss://{your-bucket-name}/data/output/part-m-00001
......参考链接
https://yq.aliyun.com/articles/292792?spm=a2c4e.11155435.0.0.7ccba82fbDwfhK
