HBASE-25818 Move StochasticLoadBalancer to hbase-balancer module

Author: Apache9

hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/LoadBalancer.java

@@ -22,7 +22,6 @@
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
-import org.apache.hadoop.conf.Configurable;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.ClusterMetrics;
 import org.apache.hadoop.hbase.ServerName;
@@ -31,6 +30,7 @@
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.conf.ConfigurationObserver;
 import org.apache.hadoop.hbase.master.balancer.ClusterInfoProvider;
+import org.apache.hadoop.hbase.master.balancer.SimpleLoadBalancer;
 import org.apache.yetus.audience.InterfaceAudience;
 
 /**
@@ -45,7 +45,7 @@
  * This class produces plans for the {@code AssignmentManager} to execute.
  */
 @InterfaceAudience.Private
-public interface LoadBalancer extends Configurable, Stoppable, ConfigurationObserver {
+public interface LoadBalancer extends Stoppable, ConfigurationObserver {
 
   // Used to signal to the caller that the region(s) cannot be assigned
   // We deliberately use 'localhost' so the operation will fail fast

hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java

@@ -96,8 +96,7 @@ protected BaseLoadBalancer(MetricsBalancer metricsBalancer) {
     this.metricsBalancer = (metricsBalancer != null) ? metricsBalancer : new MetricsBalancer();
   }
 
-  @Override
-  public void setConf(Configuration conf) {
+  protected void setConf(Configuration conf) {
     this.config = conf;
     setSlop(conf);
     if (slop < 0) {
@@ -112,7 +111,7 @@ public void setConf(Configuration conf) {
       overallSlop = 1;
     }
 
-    this.rackManager = new RackManager(getConf());
+    this.rackManager = new RackManager(config);
     useRegionFinder = config.getBoolean("hbase.master.balancer.uselocality", true);
     if (useRegionFinder) {
       regionFinder = new RegionHDFSBlockLocationFinder();
@@ -128,11 +127,6 @@ protected void setSlop(Configuration conf) {
     this.overallSlop = conf.getFloat("hbase.regions.overallSlop", slop);
   }
 
-  @Override
-  public Configuration getConf() {
-    return this.config;
-  }
-
   @Override
   public synchronized void setClusterMetrics(ClusterMetrics st) {
     this.clusterStatus = st;
@@ -145,6 +139,7 @@ public synchronized void setClusterMetrics(ClusterMetrics st) {
   @Override
   public void setClusterInfoProvider(ClusterInfoProvider provider) {
     this.provider = provider;
+    setConf(provider.getConfiguration());
     if (useRegionFinder) {
       this.regionFinder.setClusterInfoProvider(provider);
     }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/CPRequestCostFunction.java renamed to hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/CPRequestCostFunction.java

@@ -22,13 +22,15 @@
 import java.util.List;
 import java.util.Map;
 import java.util.function.Predicate;
+import java.util.function.Supplier;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.HDFSBlocksDistribution;
 import org.apache.hadoop.hbase.ServerMetrics;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.client.TableDescriptor;
+import org.apache.hadoop.hbase.master.RegionPlan;
 import org.apache.yetus.audience.InterfaceAudience;
 
 /**
@@ -38,6 +40,11 @@
 @InterfaceAudience.Private
 public interface ClusterInfoProvider {
 
+  /**
+   * Get the configuration of the given cluster.
+   */
+  Configuration getConfiguration();
+
   /**
    * Get all the regions of this cluster.
    * <p/>
@@ -78,4 +85,17 @@ List<ServerName> getOnlineServersListWithPredicator(List<ServerName> servers,
    * Get a snapshot of the current assignment status.
    */
   Map<ServerName, List<RegionInfo>> getSnapShotOfAssignment(Collection<RegionInfo> regions);
+
+  /**
+   * Test whether we are in off peak hour.
+   * <p/>
+   * For peak and off peak hours we may have different cost for the same balancing operation.
+   */
+  boolean isOffPeakHour();
+
+  /**
+   * Record the given region plans.
+   */
+  void recordBalancerDecision(List<RegionPlan> plans, double currentCost, double initCost,
+    String initFunctionTotalCosts, Supplier<String> totalCostsPerFunc, long step);
 }

hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/ClusterInfoProvider.java

@@ -15,16 +15,16 @@
 package org.apache.hadoop.hbase.master.balancer;
 
 import java.io.BufferedReader;
-import java.io.FileReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
-import java.util.ArrayList;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
-
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
@@ -33,6 +33,8 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.apache.hbase.thirdparty.com.google.common.io.CharStreams;
+
 /**
  * This is an optional Cost function designed to allow region count skew across RegionServers. A
  * rule file is loaded from the local FS or HDFS before balancing. It contains lines of rules. A
@@ -206,29 +208,17 @@ private List<String> readFile(final String filename) {
   private List<String> readFileFromHDFS(final String filename) throws IOException {
     final Path path = new Path(filename);
     final FileSystem fs = FileSystem.get(this.conf);
-    final BufferedReader reader = new BufferedReader(new InputStreamReader(fs.open(path)));
-    return readLines(reader);
+    try (BufferedReader reader =
+      new BufferedReader(new InputStreamReader(fs.open(path), StandardCharsets.UTF_8))) {
+      return CharStreams.readLines(reader);
+    }
   }
 
   /**
    * used to read the rule files from local FS
    */
   private List<String> readFileFromLocalFS(final String filename) throws IOException {
-    BufferedReader reader = new BufferedReader(new FileReader(filename));
-    return readLines(reader);
-  }
-
-  private List<String> readLines(BufferedReader reader) throws IOException {
-    final List<String> records = new ArrayList<>();
-    try {
-      String line;
-      while ((line = reader.readLine()) != null) {
-        records.add(line);
-      }
-    } finally {
-      reader.close();
-    }
-    return records;
+    return Files.readAllLines(Paths.get(filename), StandardCharsets.UTF_8);
   }
 
   /**