HDDS-8300. Enable topology aware replication and reads by default.

hadoop-hdds/common/src/main/java/org/apache/hadoop/ozone/OzoneConfigKeys.java

@@ -484,7 +484,7 @@ public final class OzoneConfigKeys {
 
   public static final String OZONE_NETWORK_TOPOLOGY_AWARE_READ_KEY =
       "ozone.network.topology.aware.read";
-  public static final boolean OZONE_NETWORK_TOPOLOGY_AWARE_READ_DEFAULT = false;
+  public static final boolean OZONE_NETWORK_TOPOLOGY_AWARE_READ_DEFAULT = true;
 
   public static final String OZONE_MANAGER_FAIR_LOCK = "ozone.om.lock.fair";
   public static final boolean OZONE_MANAGER_FAIR_LOCK_DEFAULT = false;

hadoop-hdds/common/src/main/resources/ozone-default.xml

@@ -870,7 +870,7 @@
   </property>
   <property>
     <name>ozone.scm.container.placement.impl</name>
-    <value>org.apache.hadoop.hdds.scm.container.placement.algorithms.SCMContainerPlacementRandom</value>
+    <value>org.apache.hadoop.hdds.scm.container.placement.algorithms.SCMContainerPlacementRackAware</value>
     <tag>OZONE, MANAGEMENT</tag>
     <description>
       The full name of class which implements
@@ -2753,7 +2753,7 @@
   </property>
   <property>
     <name>ozone.network.topology.aware.read</name>
-    <value>false</value>
+    <value>true</value>
     <tag>OZONE, PERFORMANCE</tag>
     <description>
       Whether to enable topology aware read to improve the read performance.

hadoop-hdds/server-scm/src/test/java/org/apache/hadoop/hdds/scm/container/placement/algorithms/TestContainerPlacementFactory.java

@@ -163,10 +163,13 @@ public void testRackAwarePolicy() throws IOException {
   }
 
   @Test
-  public void testDefaultPolicy() throws IOException {
+  public void testRackAwareContainerPolicy() throws IOException {
+    conf.set(ScmConfigKeys.OZONE_SCM_CONTAINER_PLACEMENT_IMPL_KEY,
+            SCMContainerPlacementRackAware.class.getName());
     PlacementPolicy policy = ContainerPlacementPolicyFactory
         .getPolicy(conf, null, null, true, null);
-    Assertions.assertSame(SCMContainerPlacementRandom.class, policy.getClass());
+    Assertions.assertSame(SCMContainerPlacementRackAware.class,
+            policy.getClass());
   }
 
   @Test

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/scm/TestXceiverClientGrpc.java

@@ -87,6 +87,8 @@ public void testCorrectDnsReturnedFromPipeline() throws IOException {
   @Timeout(5)
   public void testRandomFirstNodeIsCommandTarget() throws IOException {
     final ArrayList<DatanodeDetails> allDNs = new ArrayList<>(dns);
+    conf.setBoolean(
+            OzoneConfigKeys.OZONE_NETWORK_TOPOLOGY_AWARE_READ_KEY, false);
     // Using a new Xceiver Client, call it repeatedly until all DNs in the
     // pipeline have been the target of the command, indicating it is shuffling
     // the DNs on each call with a new client. This test will timeout if this