From 6c2da4bc0f8fc949fa2b9bebd4b4eeddfde544fc Mon Sep 17 00:00:00 2001
From: Todd Lipcon <todd@apache.org>
Date: Wed, 14 Dec 2011 21:41:31 +0000
Subject: [PATCH] HDFS-2680. DFSClient should construct failover proxy with
 exponential backoff. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-1623@1214487 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hadoop-hdfs/CHANGES.HDFS-1623.txt         |  2 ++
 .../org/apache/hadoop/hdfs/DFSClient.java     | 20 ++++++++++++++++++-
 .../org/apache/hadoop/hdfs/DFSConfigKeys.java |  6 ++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt
index fecb9c8c82..11a2b6b00d 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt
@@ -51,3 +51,5 @@ HDFS-2627. Determine DN's view of which NN is active based on heartbeat response
 HDFS-2634. Standby needs to ingest latest edit logs before transitioning to active (todd)
 
 HDFS-2671. NN should throw StandbyException in response to RPCs in STANDBY state (todd)
+
+HDFS-2680. DFSClient should construct failover proxy with exponential backoff (todd)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
index 43af62c46c..756899945d 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java
@@ -147,6 +147,9 @@ public class DFSClient implements java.io.Closeable {
    * DFSClient configuration 
    */
   static class Conf {
+    final int maxFailoverAttempts;
+    final int failoverSleepBaseMillis;
+    final int failoverSleepMaxMillis;
     final int maxBlockAcquireFailures;
     final int confTime;
     final int ioBufferSize;
@@ -168,6 +171,16 @@ public class DFSClient implements java.io.Closeable {
     final boolean useLegacyBlockReader;
 
     Conf(Configuration conf) {
+      maxFailoverAttempts = conf.getInt(
+          DFS_CLIENT_FAILOVER_MAX_ATTEMPTS_KEY,
+          DFS_CLIENT_FAILOVER_MAX_ATTEMPTS_DEFAULT);
+      failoverSleepBaseMillis = conf.getInt(
+          DFS_CLIENT_FAILOVER_SLEEPTIME_BASE_KEY,
+          DFS_CLIENT_FAILOVER_SLEEPTIME_BASE_DEFAULT);
+      failoverSleepMaxMillis = conf.getInt(
+          DFS_CLIENT_FAILOVER_SLEEPTIME_MAX_KEY,
+          DFS_CLIENT_FAILOVER_SLEEPTIME_MAX_DEFAULT);
+
       maxBlockAcquireFailures = conf.getInt(
           DFS_CLIENT_MAX_BLOCK_ACQUIRE_FAILURES_KEY,
           DFS_CLIENT_MAX_BLOCK_ACQUIRE_FAILURES_DEFAULT);
@@ -306,7 +319,12 @@ public class DFSClient implements java.io.Closeable {
       FailoverProxyProvider failoverProxyProvider = (FailoverProxyProvider)
           ReflectionUtils.newInstance(failoverProxyProviderClass, conf);
       this.namenode = (ClientProtocol)RetryProxy.create(ClientProtocol.class,
-          failoverProxyProvider, RetryPolicies.failoverOnNetworkException(1));
+          failoverProxyProvider,
+          RetryPolicies.failoverOnNetworkException(
+              RetryPolicies.TRY_ONCE_THEN_FAIL,
+              dfsClientConf.maxFailoverAttempts,
+              dfsClientConf.failoverSleepBaseMillis,
+              dfsClientConf.failoverSleepMaxMillis));
       nnAddress = null;
     } else if (nameNodeUri != null && rpcNamenode == null) {
       this.namenode = DFSUtil.createNamenode(NameNode.getAddress(nameNodeUri), conf);
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
index 1c9ed58192..b0a5786355 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
@@ -49,6 +49,12 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final String  DFS_CLIENT_SOCKET_CACHE_CAPACITY_KEY = "dfs.client.socketcache.capacity";
   public static final int     DFS_CLIENT_SOCKET_CACHE_CAPACITY_DEFAULT = 16;
   public static final String  DFS_CLIENT_FAILOVER_PROXY_PROVIDER_KEY_PREFIX = "dfs.client.failover.proxy.provider";
+  public static final String  DFS_CLIENT_FAILOVER_MAX_ATTEMPTS_KEY = "dfs.client.failover.max.attempts";
+  public static final int     DFS_CLIENT_FAILOVER_MAX_ATTEMPTS_DEFAULT = 15;
+  public static final String  DFS_CLIENT_FAILOVER_SLEEPTIME_BASE_KEY = "dfs.client.failover.sleep.base.millis";
+  public static final int     DFS_CLIENT_FAILOVER_SLEEPTIME_BASE_DEFAULT = 500;
+  public static final String  DFS_CLIENT_FAILOVER_SLEEPTIME_MAX_KEY = "dfs.client.failover.sleep.max.millis";
+  public static final int     DFS_CLIENT_FAILOVER_SLEEPTIME_MAX_DEFAULT = 15000;
   
   public static final String  DFS_NAMENODE_BACKUP_ADDRESS_KEY = "dfs.namenode.backup.address";
   public static final String  DFS_NAMENODE_BACKUP_ADDRESS_DEFAULT = "localhost:50100";