umamaheswararao commented on a change in pull request #1988: URL: https://github.com/apache/hadoop/pull/1988#discussion_r418743053
########## File path: hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ViewFsOverloadScheme.java ########## @@ -0,0 +1,170 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.hadoop.fs.viewfs; + +import java.io.IOException; +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; +import java.net.URI; + +import org.apache.hadoop.classification.InterfaceAudience; +import org.apache.hadoop.classification.InterfaceStability; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.FileSystem; +import org.apache.hadoop.fs.FsConstants; +import org.apache.hadoop.fs.UnsupportedFileSystemException; + +/****************************************************************************** + * This class is extended from the ViewFileSystem for the overloaded scheme file + * system. The objective here is to handle multiple mounted file systems + * transparently. Mount link configurations and in-memory mount table + * building behaviors are inherited from ViewFileSystem. Unlike ViewFileSystem + * scheme (viewfs://), the users would be able to use any scheme. + * + * Example 1: + * If users want some of their existing cluster (hdfs://Cluster) + * data to mount with other hdfs and object store clusters(hdfs://NN1, + * o3fs://bucket1.volume1/, s3a://bucket1/) + * + * fs.viewfs.mounttable.Cluster./user = hdfs://NN1/user + * fs.viewfs.mounttable.Cluster./data = o3fs://bucket1.volume1/data + * fs.viewfs.mounttable.Cluster./backup = s3a://bucket1/backup/ + * + * Op1: Create file hdfs://Cluster/user/fileA will go to hdfs://NN1/user/fileA + * Op2: Create file hdfs://Cluster/data/datafile will go to + * o3fs://bucket1.volume1/data/datafile + * Op3: Create file hdfs://Cluster/backup/data.zip will go to + * s3a://bucket1/backup/data.zip + * + * Example 2: + * If users want some of their existing cluster (s3a://bucketA/) + * data to mount with other hdfs and object store clusters + * (hdfs://NN1, o3fs://bucket1.volume1/) + * + * fs.viewfs.mounttable.bucketA./user = hdfs://NN1/user + * fs.viewfs.mounttable.bucketA./data = o3fs://bucket1.volume1/data + * fs.viewfs.mounttable.bucketA./salesDB = s3a://bucketA/salesDB/ + * + * Op1: Create file s3a://bucketA/user/fileA will go to hdfs://NN1/user/fileA + * Op2: Create file s3a://bucketA/data/datafile will go to + * o3fs://bucket1.volume1/data/datafile + * Op3: Create file s3a://bucketA/salesDB/dbfile will go to + * s3a://bucketA/salesDB/dbfile + *****************************************************************************/ [email protected]({ "MapReduce", "HBase", "Hive" }) [email protected] +public class ViewFsOverloadScheme extends ViewFileSystem { Review comment: Sure I will add logging for this. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
