HDFS回收站

hdfs会为每一个用户创建一个回收站目录:/usr用户名/.Trash/,每一个用户在Shell命令行删除的文件/目录，会进入到对应的回收站目录中，在回收站中的数据都有一个生命周期，也就是说当回收站中的文件/目录在一段时间之内没有被用户恢复的话，HDFS就会自动将这个文件/目录彻底删除。
默认情况下hdfs的回收站是不开启的，需要通过配置来开启，位置core-site.xml,配置如下，value的单位是分钟，1440分钟代表的是一天的生命周期

 <property>
         <name>fs.trash.interval</name>
        <value>1440</value>
   </property>

1440代表的是一天。24*60=1440
修改配置需同步集群中其他节点信息，并重启集群
重启集群后尝试删除REDADME.txt文件

[root@bigdata02 hadoop]# hdfs dfs -rm /README.txt
2021-04-03 10:56:08,152 INFO fs.TrashPolicyDefault: Moved: 'hdfs://bigdata02:9000/README.txt' to trash at: hdfs://bigdata02:9000/user/root/.Trash/Current/README.txt
[root@bigdata02 hadoop]# hdfs dfs -ls /user/root/.Trash/Current
Found 2 items
-rw-r--r--   2 root supergroup       1361 2021-04-03 10:14 /user/root/.Trash/Current/README.txt
-rw-r--r--   2 root supergroup  345625475 2021-04-03 09:53 /user/root/.Trash/Current/hadoop-3.2.0.tar.gz
[root@bigdata02 hadoop]# hdfs dfs -rm -r /user/root/.Trash/Current/Current/hadoop-3.2.0.tar.gz
rm: `/user/root/.Trash/Current/Current/hadoop-3.2.0.tar.gz': No such file or directory

如果文件大，可带-skipTrash参数直接进行删除

[root@bigdata02 hadoop]# hdfs dfs -rm -r -skipTrash /hadoop-3.2.0.tar.gz
Deleted /hadoop-3.2.0.tar.gz

HDFS安全模式

集群刚启动时HDFS会进入安全模式，此时无法执行操作。

[root@bigdata02 hadoop]# hdfs dfs -rm /README.txt
2021-04-03 10:55:41,520 WARN fs.TrashPolicyDefault: Can't create trash directory: hdfs://bigdata02:9000/user/root/.Trash/Current
org.apache.hadoop.hdfs.server.namenode.SafeModeException: Cannot create directory /user/root/.Trash/Current. Name node is in safe mode.
The reported blocks 4 has reached the threshold 0.9990 of total blocks 4. The number of live datanodes 2 has reached the minimum number 0. In safe mode extension. Safe mode will be turned off automatically in 1 seconds. NamenodeHostName:bigdata02
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.newSafemodeException(FSNamesystem.java:1469)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkNameNodeSafeMode(FSNamesystem.java:1456)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:3214)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.mkdirs(NameNodeRpcServer.java:1127)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.mkdirs(ClientNamenodeProtocolServerSideTranslatorPB.java:713)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:524)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1025)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:876)
        at org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:822)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1730)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2682)

    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.apache.hadoop.ipc.RemoteException.instantiateException(RemoteException.java:121)
    at org.apache.hadoop.ipc.RemoteException.unwrapRemoteException(RemoteException.java:88)
    at org.apache.hadoop.hdfs.DFSClient.primitiveMkdir(DFSClient.java:2426)
    at org.apache.hadoop.hdfs.DFSClient.mkdirs(DFSClient.java:2400)
    at org.apache.hadoop.hdfs.DistributedFileSystem$27.doCall(DistributedFileSystem.java:1324)
    at org.apache.hadoop.hdfs.DistributedFileSystem$27.doCall(DistributedFileSystem.java:1321)
    at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
    at org.apache.hadoop.hdfs.DistributedFileSystem.mkdirsInternal(DistributedFileSystem.java:1338)
    at org.apache.hadoop.hdfs.DistributedFileSystem.mkdirs(DistributedFileSystem.java:1313)
    at org.apache.hadoop.fs.TrashPolicyDefault.moveToTrash(TrashPolicyDefault.java:153)
    at org.apache.hadoop.fs.Trash.moveToTrash(Trash.java:110)
    at org.apache.hadoop.fs.Trash.moveToAppropriateTrash(Trash.java:96)
    at org.apache.hadoop.fs.shell.Delete$Rm.moveToTrash(Delete.java:153)
    at org.apache.hadoop.fs.shell.Delete$Rm.processPath(Delete.java:118)
    at org.apache.hadoop.fs.shell.Command.processPathInternal(Command.java:367)
    at org.apache.hadoop.fs.shell.Command.processPaths(Command.java:331)
    at org.apache.hadoop.fs.shell.Command.processPathArgument(Command.java:304)
    at org.apache.hadoop.fs.shell.Command.processArgument(Command.java:286)
    at org.apache.hadoop.fs.shell.Command.processArguments(Command.java:270)
    at org.apache.hadoop.fs.shell.FsCommand.processRawArguments(FsCommand.java:120)
    at org.apache.hadoop.fs.shell.Command.run(Command.java:177)
    at org.apache.hadoop.fs.FsShell.run(FsShell.java:327)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:90)
    at org.apache.hadoop.fs.FsShell.main(FsShell.java:390)

Caused by: org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.namenode.SafeModeException): Cannot create directory /user/root/.Trash/Current. Name node is in safe mode.
The reported blocks 4 has reached the threshold 0.9990 of total blocks 4. The number of live datanodes 2 has reached the minimum number 0. In safe mode extension. Safe mode will be turned off automatically in 1 seconds. NamenodeHostName:bigdata02
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.newSafemodeException(FSNamesystem.java:1469)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkNameNodeSafeMode(FSNamesystem.java:1456)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:3214)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.mkdirs(NameNodeRpcServer.java:1127)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.mkdirs(ClientNamenodeProtocolServerSideTranslatorPB.java:713)
at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos(ClientNamenodeProtocol)2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
at org.apache.hadoop.ipc.ProtobufRpcEngine(Server)ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:524)
at org.apache.hadoop.ipc.RPC(Server.call(RPC.java:1025)
at org.apache.hadoop.ipc.Server)RpcCall.run(Server.java:876)
at org.apache.hadoop.ipc.Server(RpcCall.run(Server.java:822)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:422)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1730)
at org.apache.hadoop.ipc.Server)Handler.run(Server.java:2682)

    at org.apache.hadoop.ipc.Client.getRpcResponse(Client.java:1511)
    at org.apache.hadoop.ipc.Client.call(Client.java:1457)
    at org.apache.hadoop.ipc.Client.call(Client.java:1367)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:228)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:116)
    at com.sun.proxy.$Proxy9.mkdirs(Unknown Source)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.mkdirs(ClientNamenodeProtocolTranslatorPB.java:656)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:422)
    at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeMethod(RetryInvocationHandler.java:165)
    at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invoke(RetryInvocationHandler.java:157)
    at org.apache.hadoop.io.retry.RetryInvocationHandler$Call.invokeOnce(RetryInvocationHandler.java:95)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:359)
    at com.sun.proxy.$Proxy10.mkdirs(Unknown Source)
    at org.apache.hadoop.hdfs.DFSClient.primitiveMkdir(DFSClient.java:2424)
    ... 22 more

rm: Failed to move to trash: hdfs://bigdata02:9000/README.txt: Cannot create directory /user/root/.Trash/Current. Name node is in safe mode.
[root@bigdata02 hadoop]# hdfs dfs -rm /README.txt
2021-04-03 10:56:08,152 INFO fs.TrashPolicyDefault: Moved: 'hdfs://bigdata02:9000/README.txt' to trash at: hdfs://bigdata02:9000/user/root/.Trash/Current/README.txt

查看安全模式

[root@bigdata02 hadoop]# hdfs dfsadmin -safemode get
Safe mode is OFF

离开安全模式

[root@bigdata02 hadoop]# hdfs dfsadmin -safemode leave
Safe mode is OFF