From 5572f73d45842308aba890c0eb89fe456154cd00 Mon Sep 17 00:00:00 2001 From: Tsz-wo Sze Date: Fri, 15 Jun 2012 23:00:36 +0000 Subject: [PATCH] HDFS-3518. Add a utility method HdfsUtils.isHealthy(uri) for checking if the given HDFS is healthy. git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1350825 13f79535-47bb-0310-9956-ffa450edef68 --- hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt | 7 +- .../hadoop/hdfs/DistributedFileSystem.java | 2 +- .../apache/hadoop/hdfs/client/HdfsUtils.java | 87 +++++++++++++++++++ .../hadoop/hdfs/TestDFSClientRetries.java | 16 +++- 4 files changed, 108 insertions(+), 4 deletions(-) create mode 100644 hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/client/HdfsUtils.java diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt index 461850c54fd..fc632047c8e 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt +++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt @@ -13,8 +13,6 @@ Trunk (unreleased changes) HDFS-3125. Add JournalService to enable Journal Daemon. (suresh) - HDFS-744. Support hsync in HDFS. (Lars Hofhansl via szetszwo) - IMPROVEMENTS HDFS-1620. Rename HdfsConstants -> HdfsServerConstants, FSConstants -> @@ -162,9 +160,14 @@ Branch-2 ( Unreleased changes ) NEW FEATURES + HDFS-744. Support hsync in HDFS. (Lars Hofhansl via szetszwo) + HDFS-3042. Automatic failover support for NameNode HA (todd) (see dedicated section below for breakdown of subtasks) + HDFS-3518. Add a utility method HdfsUtils.isHealthy(uri) for checking if + the given HDFS is healthy. (szetszwo) + IMPROVEMENTS HDFS-3390. DFSAdmin should print full stack traces of errors when DEBUG diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java index 1de353bdb8b..8c0ed10d2bd 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java @@ -96,7 +96,7 @@ public DistributedFileSystem() { */ @Override public String getScheme() { - return "hdfs"; + return HdfsConstants.HDFS_URI_SCHEME; } @Deprecated diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/client/HdfsUtils.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/client/HdfsUtils.java new file mode 100644 index 00000000000..9133cf31817 --- /dev/null +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/client/HdfsUtils.java @@ -0,0 +1,87 @@ +/** + * 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.hdfs.client; + +import java.io.IOException; +import java.net.URI; + +import org.apache.commons.logging.Log; +import org.apache.commons.logging.LogFactory; +import org.apache.hadoop.classification.InterfaceAudience; +import org.apache.hadoop.classification.InterfaceStability; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.CommonConfigurationKeysPublic; +import org.apache.hadoop.fs.FileSystem; +import org.apache.hadoop.hdfs.DFSConfigKeys; +import org.apache.hadoop.hdfs.DistributedFileSystem; +import org.apache.hadoop.hdfs.protocol.HdfsConstants; +import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction; +import org.apache.hadoop.io.IOUtils; + +/** + * The public utility API for HDFS. + */ +@InterfaceAudience.Public +@InterfaceStability.Evolving +public class HdfsUtils { + private static final Log LOG = LogFactory.getLog(HdfsUtils.class); + + /** + * Is the HDFS healthy? + * HDFS is considered as healthy if it is up and not in safemode. + * + * @param uri the HDFS URI. Note that the URI path is ignored. + * @return true if HDFS is healthy; false, otherwise. + */ + public static boolean isHealthy(URI uri) { + //check scheme + final String scheme = uri.getScheme(); + if (!HdfsConstants.HDFS_URI_SCHEME.equalsIgnoreCase(scheme)) { + throw new IllegalArgumentException("The scheme is not " + + HdfsConstants.HDFS_URI_SCHEME + ", uri=" + uri); + } + + final Configuration conf = new Configuration(); + //disable FileSystem cache + conf.setBoolean(String.format("fs.%s.impl.disable.cache", scheme), true); + //disable client retry for rpc connection and rpc calls + conf.setBoolean(DFSConfigKeys.DFS_CLIENT_RETRY_POLICY_ENABLED_KEY, false); + conf.setInt( + CommonConfigurationKeysPublic.IPC_CLIENT_CONNECT_MAX_RETRIES_KEY, 0); + + DistributedFileSystem fs = null; + try { + fs = (DistributedFileSystem)FileSystem.get(uri, conf); + final boolean safemode = fs.setSafeMode(SafeModeAction.SAFEMODE_GET); + if (LOG.isDebugEnabled()) { + LOG.debug("Is namenode in safemode? " + safemode + "; uri=" + uri); + } + + fs.close(); + fs = null; + return !safemode; + } catch(IOException e) { + if (LOG.isDebugEnabled()) { + LOG.debug("Got an exception for uri=" + uri, e); + } + return false; + } finally { + IOUtils.cleanup(LOG, fs); + } + } +} diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSClientRetries.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSClientRetries.java index 4d8244dde73..44e4f9fd232 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSClientRetries.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSClientRetries.java @@ -31,6 +31,7 @@ import java.io.OutputStream; import java.net.InetSocketAddress; import java.net.SocketTimeoutException; +import java.net.URI; import java.security.MessageDigest; import java.util.ArrayList; import java.util.Arrays; @@ -51,6 +52,7 @@ import org.apache.hadoop.fs.Path; import org.apache.hadoop.fs.UnresolvedLinkException; import org.apache.hadoop.fs.permission.FsPermission; +import org.apache.hadoop.hdfs.client.HdfsUtils; import org.apache.hadoop.hdfs.protocol.Block; import org.apache.hadoop.hdfs.protocol.ClientDatanodeProtocol; import org.apache.hadoop.hdfs.protocol.DatanodeID; @@ -823,9 +825,11 @@ public void testNamenodeRestart() throws Exception { .build(); try { cluster.waitActive(); + final DistributedFileSystem dfs = cluster.getFileSystem(); + final URI uri = dfs.getUri(); + assertTrue(HdfsUtils.isHealthy(uri)); //create a file - final DistributedFileSystem dfs = cluster.getFileSystem(); final long length = 1L << 20; final Path file1 = new Path(dir, "foo"); DFSTestUtil.createFile(dfs, file1, length, numDatanodes, 20120406L); @@ -835,7 +839,9 @@ public void testNamenodeRestart() throws Exception { assertEquals(length, s1.getLen()); //shutdown namenode + assertTrue(HdfsUtils.isHealthy(uri)); cluster.shutdownNameNode(0); + assertFalse(HdfsUtils.isHealthy(uri)); //namenode is down, create another file in a thread final Path file3 = new Path(dir, "file"); @@ -860,8 +866,10 @@ public void run() { try { //sleep, restart, and then wait active TimeUnit.SECONDS.sleep(30); + assertFalse(HdfsUtils.isHealthy(uri)); cluster.restartNameNode(0, false); cluster.waitActive(); + assertTrue(HdfsUtils.isHealthy(uri)); } catch (Exception e) { exceptions.add(e); } @@ -877,7 +885,9 @@ public void run() { assertEquals(dfs.getFileChecksum(file1), dfs.getFileChecksum(file3)); //enter safe mode + assertTrue(HdfsUtils.isHealthy(uri)); dfs.setSafeMode(SafeModeAction.SAFEMODE_ENTER); + assertFalse(HdfsUtils.isHealthy(uri)); //leave safe mode in a new thread new Thread(new Runnable() { @@ -886,7 +896,9 @@ public void run() { try { //sleep and then leave safe mode TimeUnit.SECONDS.sleep(30); + assertFalse(HdfsUtils.isHealthy(uri)); dfs.setSafeMode(SafeModeAction.SAFEMODE_LEAVE); + assertTrue(HdfsUtils.isHealthy(uri)); } catch (Exception e) { exceptions.add(e); } @@ -898,6 +910,8 @@ public void run() { DFSTestUtil.createFile(dfs, file2, length, numDatanodes, 20120406L); assertEquals(dfs.getFileChecksum(file1), dfs.getFileChecksum(file2)); + assertTrue(HdfsUtils.isHealthy(uri)); + //make sure it won't retry on exceptions like FileNotFoundException final Path nonExisting = new Path(dir, "nonExisting"); LOG.info("setPermission: " + nonExisting);