HDFS-12183. Ozone: KSM : Use proper defaults for block client address. Contributed by Lokesh Jain.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/OzoneClientUtils.java

@@ -169,22 +169,29 @@ public final class OzoneClientUtils {
 
   /**
    * Retrieve the socket address that should be used by clients to connect
-   * to the SCM for block service.
+   * to the SCM for block service. If
+   * {@link ScmConfigKeys#OZONE_SCM_BLOCK_CLIENT_ADDRESS_KEY} is not defined
+   * then {@link ScmConfigKeys#OZONE_SCM_CLIENT_ADDRESS_KEY} is used.
    *
    * @param conf
    * @return Target InetSocketAddress for the SCM block client endpoint.
+   * @throws IllegalArgumentException if configuration is not defined.
    */
   public static InetSocketAddress getScmAddressForBlockClients(
       Configuration conf) {
-    final Optional<String> host = getHostNameFromConfigKeys(conf,
+    Optional<String> host = getHostNameFromConfigKeys(conf,
         ScmConfigKeys.OZONE_SCM_BLOCK_CLIENT_ADDRESS_KEY);
 
     if (!host.isPresent()) {
-      throw new IllegalArgumentException(
-          ScmConfigKeys.OZONE_SCM_BLOCK_CLIENT_ADDRESS_KEY +
-          " must be defined. See" +
-          " https://wiki.apache.org/hadoop/Ozone#Configuration for details" +
-          " on configuring Ozone.");
+      host = getHostNameFromConfigKeys(conf,
+              ScmConfigKeys.OZONE_SCM_CLIENT_ADDRESS_KEY);
+      if (!host.isPresent()) {
+        throw new IllegalArgumentException(
+                ScmConfigKeys.OZONE_SCM_BLOCK_CLIENT_ADDRESS_KEY +
+                        " must be defined. See" +
+                        " https://wiki.apache.org/hadoop/Ozone#Configuration for details" +
+                        " on configuring Ozone.");
+      }
     }
 
     final Optional<Integer> port = getPortNumberFromConfigKeys(conf,

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/ozone-default.xml

@@ -171,7 +171,8 @@
     <name>ozone.scm.block.client.address</name>
     <value></value>
     <description>
-      The address of the Ozone SCM block client service.
+      The address of the Ozone SCM block client service. If not defined
+      value of ozone.scm.client.address is used.
     </description>
   </property>