hadoop学习笔记:hdfs常用命令

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一、hadoop fs

1、创建目录

[[email protected] hadoop-2.7.0]# hadoop fs -mkdir /testdir1
[[email protected] hadoop-2.7.0]# hadoop fs -ls /
Found 2 items
drwxr-xr-x   - root supergroup          0 2018-05-07 11:27 /test
drwxr-xr-x   - root supergroup          0 2018-05-18 09:27 /testdir1

加 -p 则创建多级目录

[[email protected] hadoop-2.7.0]# hadoop fs -mkdir -p /aa/bb/cc
[[email protected] hadoop-2.7.0]# hadoop fs -ls /
Found 3 items
drwxr-xr-x   - root supergroup          0 2018-05-18 09:28 /aa
drwxr-xr-x   - root supergroup          0 2018-05-07 11:27 /test
drwxr-xr-x   - root supergroup          0 2018-05-18 09:27 /testdir1

 

2、ls,列出指定目录的所有文件或文件夹

[[email protected] hadoop-2.7.0]# hadoop fs -ls /
Found 1 items
drwxr-xr-x   - root supergroup          0 2018-05-07 11:27 /test

加 -R,列出所有级的目录和文件

[[email protected] hadoop-2.7.0]# hadoop fs -ls -R /
drwxr-xr-x   - root supergroup          0 2018-05-18 09:28 /aa
drwxr-xr-x   - root supergroup          0 2018-05-18 09:28 /aa/bb
drwxr-xr-x   - root supergroup          0 2018-05-18 09:28 /aa/bb/cc
drwxr-xr-x   - root supergroup          0 2018-05-07 11:27 /test
drwxr-xr-x   - root supergroup          0 2018-05-18 09:27 /testdir1

3、copeFromLocal,复制本地文件到hdfs的目录,除了限定源路径是一个本地文件外,和put命令相似,如果要强制复制文件 加-f 也可以一次复制多个文件

[[email protected] hadoop-2.7.0]# touch /root/file1.txt
[[email protected] hadoop-2.7.0]# hadoop  fs -copyFromLocal /root/file1.txt /testdir1
[[email protected] hadoop-2.7.0]# hadoop fs -ls  /testdir1
Found 1 items
-rw-r--r--   2 root supergroup          0 2018-05-18 09:33 /testdir1/file1.txt

4、put,复制文件到hdfs中,文件可以从标准输入中读取(与copeFromLocal不同点,此时dst是一个文件)。

使用方法: hadoop fs -put <localsrc> ... <dst>

1)从本地文件复到hdfs的文件夹(与copeFromLocal相同)

[[email protected] hadoop-2.7.0]# hadoop fs -put /root/file1.txt /aa
[[email protected] hadoop-2.7.0]# hadoop fs -ls  /aa
Found 2 items
drwxr-xr-x   - root supergroup          0 2018-05-18 09:28 /aa/bb
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt

2) 从标准输入流中写入到hdfs中

[[email protected] hadoop-2.7.0]# echo abc | hadoop fs -put - /aa/file2.txt 
[[email protected] hadoop-2.7.0]# hadoop fs -ls  /aa
Found 3 items
drwxr-xr-x   - root supergroup          0 2018-05-18 09:28 /aa/bb
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt
-rw-r--r--   2 root supergroup          4 2018-05-18 09:44 /aa/file2.txt

5、cat,列出文件的内容

[[email protected] hadoop-2.7.0]# hadoop fs -cat  /test/readme.txt
total 0
drwxr-xr-x.  3 root  root   18 May  7 10:21 dfs
drwxr-xr-x. 10 10021 10021 161 May  7 10:22 hadoop-2.7.0
drwxr-xr-x.  4 root  root   30 May  7 09:15 hdfs
drwxr-xr-x.  3 root  root   17 May  7 10:41 tmp

如果文件过大可以在后面加|more就可以一页一页的显示

 hadoop fs -cat  /test/readme.txt|more

6、rm,删除文件或目录

1)删除文件

[[email protected] hadoop-2.7.0]# hadoop fs -rm  /aa/file2.txt
rm: Failed to get server trash configuration: null. Consider using -skipTrash option
[[email protected] hadoop-2.7.0]# hadoop fs -rm -skipTrash  /aa/file2.txt
Deleted /aa/file2.txt

2)删除目录

[[email protected] hadoop-2.7.0]# hadoop fs -rm -r -skipTrash  /aa/bb
Deleted /aa/bb
[[email protected] hadoop-2.7.0]# hadoop fs -ls /aa
Found 1 items
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt

7、cp,在hdfs内部复文件,这个命令允许有多个源路径,此时目标路径必须是一个目录

[[email protected] hadoop-2.7.0]# hadoop fs -cp /aa/file1.txt /aa/file3.txt
18/05/18 10:01:01 WARN hdfs.DFSClient: DFSInputStream has been closed already
[[email protected] hadoop-2.7.0]# hadoop fs -ls /aa
Found 2 items
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt
-rw-r--r--   2 root supergroup          0 2018-05-18 10:01 /aa/file3.txt

8、get,将文件从hdfs复制到本地

[[email protected] hadoop-2.7.0]# hadoop fs -get /aa/file3.txt /root/
18/05/18 10:04:11 WARN hdfs.DFSClient: DFSInputStream has been closed already
[[email protected] hadoop-2.7.0]# ll /root/
total 8
-rw-------. 1 root root 1260 Apr 19 18:36 anaconda-ks.cfg
-rw-r--r--. 1 root root  784 Apr 19 11:35 authorized_keys
-rw-r--r--. 1 root root    0 May 18 09:32 file1.txt
-rw-r--r--. 1 root root    0 May 18 10:04 file3.txt

9、copyToLocal,除了限定目标路径是一个本地文件外,和get命令类似

10、mv,在hdfs内部移动文件

[[email protected] hadoop-2.7.0]# hadoop fs -mv /aa/file3.txt /aa/file4.txt
[[email protected] hadoop-2.7.0]# hadoop fs -ls /aa
Found 2 items
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt
-rw-r--r--   2 root supergroup          0 2018-05-18 10:01 /aa/file4.txt

总结用法与Linux命令类似,不再一一列了

 

二、hdfs dfsadmin 管理命令

1、-report,查看文件系统的信息和统计信息

[[email protected] hadoop-2.7.0]# hdfs dfsadmin -report
Configured Capacity: 47204802560 (43.96 GB)
Present Capacity: 43612942336 (40.62 GB)
DFS Remaining: 43612909568 (40.62 GB)
DFS Used: 32768 (32 KB)
DFS Used%: 0.00%
Under replicated blocks: 0
Blocks with corrupt replicas: 0
Missing blocks: 0
Missing blocks (with replication factor 1): 0

-------------------------------------------------
Live datanodes (2):

Name: 192.168.137.102:50010 (node2)
Hostname: node2
Decommission Status : Normal
Configured Capacity: 23602401280 (21.98 GB)
DFS Used: 16384 (16 KB)
Non DFS Used: 1795612672 (1.67 GB)
DFS Remaining: 21806772224 (20.31 GB)
DFS Used%: 0.00%
DFS Remaining%: 92.39%
Configured Cache Capacity: 0 (0 B)
Cache Used: 0 (0 B)
Cache Remaining: 0 (0 B)
Cache Used%: 100.00%
Cache Remaining%: 0.00%
Xceivers: 1
Last contact: Fri May 18 10:13:58 EDT 2018


Name: 192.168.137.101:50010 (node1)
Hostname: node1
Decommission Status : Normal
Configured Capacity: 23602401280 (21.98 GB)
DFS Used: 16384 (16 KB)
Non DFS Used: 1796247552 (1.67 GB)
DFS Remaining: 21806137344 (20.31 GB)
DFS Used%: 0.00%
DFS Remaining%: 92.39%
Configured Cache Capacity: 0 (0 B)
Cache Used: 0 (0 B)
Cache Remaining: 0 (0 B)
Cache Used%: 100.00%
Cache Remaining%: 0.00%
Xceivers: 1
Last contact: Fri May 18 10:13:58 EDT 2018

2、-safemode,enter | leave | get | wait:安全模式命令。安全模式是NameNode的一种状态,在这种状态下,NameNode不接受对名字空间的更改(只读);不复制或删除块。NameNode在启动时自动进入安全模式,当配置块的最小百分数满足最小副本数的条件时,会自动离开安全模式。enter是进入,leave是离开。

[[email protected] hadoop-2.7.0]# hdfs dfsadmin -safemode get
Safe mode is OFF
[[email protected] hadoop-2.7.0]# hdfs dfsadmin -safemode enter
Safe mode is ON
[[email protected] hadoop-2.7.0]# hadoop fs -ls /aa
Found 2 items
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt
-rw-r--r--   2 root supergroup          0 2018-05-18 10:01 /aa/file4.txt
[[email protected] hadoop-2.7.0]# hadoop fs -rm -skipTrash /aa/file4.txt
rm: Cannot delete /aa/file4.txt. Name node is in safe mode.

3、-refreshNodes,重新读取hosts和exclude文件,使新的节点或需要退出集群的节点能够被NameNode重新识别。这个命令在新增节点或注销节点时用到。

[[email protected] hadoop-2.7.0]# hdfs dfsadmin -refreshNodes
Refresh nodes successful

4、-finalizeUpgrade,终结HDFS的升级操作。Datanode删除前一个版本的工作目录,之后Namenode也这样做。这个操作完结整个升级过程。

[[email protected] hadoop-2.7.0]# hdfs dfsadmin -finalizeUpgrade
Finalize upgrade successful

5、-metasave filename,保存Namenode的主要数据结构到hadoop.log.dir属性指定的目录(默认值是hadoop安装目录:/home/hadoop/hadoop-2.7.0)下的<filename>文件。对于下面的每一项,<filename>中都会一行内容与之对应
1. Namenode收到的Datanode的心跳信号
2. 等待被复制的块
3. 正在被复制的块
4. 等待被删除的块

[[email protected] hadoop-2.7.0]# hdfs dfsadmin -metasave newlog.log
Created metasave file newlog.log in the log directory of namenode hdfs://192.168.137.100:9000
[[email protected] logs]# pwd
/home/hadoop/hadoop-2.7.0/logs
[[email protected] logs]# ll
total 940
-rw-r--r--. 1 root root 254161 May 18 10:26 hadoop-root-namenode-master.log
-rw-r--r--. 1 root root    714 May 18 09:21 hadoop-root-namenode-master.out
-rw-r--r--. 1 root root    714 May  7 11:36 hadoop-root-namenode-master.out.1
-rw-r--r--. 1 root root    714 May  7 11:24 hadoop-root-namenode-master.out.2
-rw-r--r--. 1 root root    714 May  7 11:19 hadoop-root-namenode-master.out.3
-rw-r--r--. 1 root root    714 May  7 11:00 hadoop-root-namenode-master.out.4
-rw-r--r--. 1 root root    714 May  7 10:49 hadoop-root-namenode-master.out.5
-rw-r--r--. 1 root root 267631 May 18 10:16 hadoop-root-secondarynamenode-master.log
-rw-r--r--. 1 root root    714 May 18 09:21 hadoop-root-secondarynamenode-master.out
-rw-r--r--. 1 root root    714 May  7 11:36 hadoop-root-secondarynamenode-master.out.1
-rw-r--r--. 1 root root    714 May  7 11:24 hadoop-root-secondarynamenode-master.out.2
-rw-r--r--. 1 root root   6074 May  7 11:21 hadoop-root-secondarynamenode-master.out.3
-rw-r--r--. 1 root root   1067 May  7 11:10 hadoop-root-secondarynamenode-master.out.4
-rw-r--r--. 1 root root  12148 May  7 11:05 hadoop-root-secondarynamenode-master.out.5
-rw-r--r--. 1 root root    582 May 18 10:33 newlog.log
-rw-r--r--. 1 root root      0 May  7 10:22 SecurityAuth-root.audit
-rw-r--r--. 1 root root 340628 May 18 09:31 yarn-root-resourcemanager-master.log
-rw-r--r--. 1 root root    700 May 18 09:21 yarn-root-resourcemanager-master.out
-rw-r--r--. 1 root root    700 May  7 11:36 yarn-root-resourcemanager-master.out.1
-rw-r--r--. 1 root root    700 May  7 11:24 yarn-root-resourcemanager-master.out.2
-rw-r--r--. 1 root root    700 May  7 11:19 yarn-root-resourcemanager-master.out.3
-rw-r--r--. 1 root root    700 May  7 11:10 yarn-root-resourcemanager-master.out.4
-rw-r--r--. 1 root root    700 May  7 11:00 yarn-root-resourcemanager-master.out.5

6、-setQuota <quota> <dirname>...<dirname>,为每个目录 <dirname>设定配额<quota>。目录配额是一个长整型整数N,强制限定了目录树下的名字个数。
命令会在这个目录上工作良好,以下情况会报错:
1. N不是一个正整数,或者
2. 用户不是管理员,或者
3. 这个目录不存在或是文件,或者
4. 目录会马上超出新设定的配额。

[[email protected] hadoop-2.7.0]# hadoop fs -ls /aa
Found 2 items
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt
-rw-r--r--   2 root supergroup          0 2018-05-18 10:01 /aa/file4.txt
[[email protected] hadoop-2.7.0]# 
[[email protected] hadoop-2.7.0]# 
[[email protected] hadoop-2.7.0]# hdfs dfsadmin -setQuota 3 /aa
[[email protected] hadoop-2.7.0]# hadoop fs -touchz /aa/file5.txt
touchz: The NameSpace quota (directories and files) of directory /aa is exceeded: quota=3 file count=4
[[email protected] hadoop-2.7.0]# hadoop fs -ls /aa
Found 2 items
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt
-rw-r--r--   2 root supergroup          0 2018-05-18 10:01 /aa/file4.txt
[[email protected] hadoop-2.7.0]# hadoop fs -ls -R /aa
-rw-r--r--   2 root supergroup          0 2018-05-18 09:40 /aa/file1.txt
-rw-r--r--   2 root supergroup          0 2018-05-18 10:01 /aa/file4.txt
[[email protected] hadoop-2.7.0]# hadoop fs -touchz /aa/fi.txt
touchz: The NameSpace quota (directories and files) of directory /aa is exceeded: quota=3 file count=4
[[email protected] hadoop-2.7.0]# 

[[email protected] hadoop-2.7.0]# hdfs dfsadmin -setQuota 6 /aa
[[email protected] hadoop-2.7.0]# hadoop fs -touchz /aa/file5.txt

7、-clrQuota <dirname>...<dirname>,为每一个目录<dirname>清除配额设定。
命令会在这个目录上工作良好,以下情况会报错:
1. 这个目录不存在或是文件,或者
2. 用户不是管理员。
如果目录原来没有配额不会报错。

hdfs dfsadmin -clrQuota /aa

 














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