Fix Blueprint export handling of properties containing nameservice references

This patch implements a fix for AMBARI-7458.

This patch updates the BlueprintConfigurationProcessor such
  that properties that can contain a namservice reference (there
  are only two known properties at this point) are not removed by
  the BlueprintConfigurationProcessor during the export process.

Previously, these properties were removed, since they didn't contain
  hostname information. In a NameNode HA scenario, these particular
  properties will reference nameservices, so this problem would only
  occur when NameNode HA is enabled.

This patch addresses the immediate problem, but in the longer-term
  the stack definitions should be updated to include HA-related
  metadata, so that the Blueprint processor can determine which
  properties are modified in an HA scenario.

This patch also implements a new unit test to verify this change.

ambari-server/src/main/java/org/apache/ambari/server/controller/internal/BlueprintConfigurationProcessor.java

@@ -19,12 +19,14 @@
 package org.apache.ambari.server.controller.internal;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -74,6 +76,14 @@ public class BlueprintConfigurationProcessor {
    */
   private static Pattern HOSTGROUP_PORT_REGEX = Pattern.compile("%HOSTGROUP::(\\w+|\\d+)%:?(\\d+)?");
 
+  /**
+   * Statically-defined set of properties that can support using a nameservice name
+   *   in the configuration, rather than just a host name.
+   */
+  private static Set<String> configPropertiesWithHASupport =
+    new HashSet<String>(Arrays.asList("fs.defaultFS", "hbase.rootdir"));
+
+
   /**
    * Configuration properties to be updated
    */
@@ -290,7 +300,10 @@ public class BlueprintConfigurationProcessor {
               break;
             }
           }
-          if (! matchedHost) {
+          // remove properties that do not contain hostnames,
+          // except in the case of HA-related properties, that
+          // can contain nameservice references instead of hostnames (Fix for Bug AMBARI-7458).
+          if (! matchedHost && ! isNameServiceProperty(propertyName)) {
             typeProperties.remove(propertyName);
           }
         }
@@ -298,6 +311,19 @@ public class BlueprintConfigurationProcessor {
     }
   }
 
+  /**
+   * Determines if a given property name's value can include
+   *   nameservice references instead of host names.
+   *
+   * @param propertyName name of the property
+   *
+   * @return true if this property can support using nameservice names
+   *         false if this property cannot support using nameservice names
+   */
+  private static boolean isNameServiceProperty(String propertyName) {
+    return configPropertiesWithHASupport.contains(propertyName);
+  }
+
   /**
    * Update multi host topology configuration properties for blueprint export.
    *

ambari-server/src/test/java/org/apache/ambari/server/controller/internal/BlueprintConfigurationProcessorTest.java

@@ -1135,8 +1135,15 @@ public class BlueprintConfigurationProcessorTest {
 
     Map<String, String> hdfsSiteProperties =
       new HashMap<String, String>();
+    Map<String, String> coreSiteProperties =
+      new HashMap<String, String>();
+    Map<String, String> hbaseSiteProperties =
+      new HashMap<String, String>();
+
 
     configProperties.put("hdfs-site", hdfsSiteProperties);
+    configProperties.put("core-site", coreSiteProperties);
+    configProperties.put("hbase-site", hbaseSiteProperties);
 
     // setup hdfs config for test
 
@@ -1152,7 +1159,6 @@ public class BlueprintConfigurationProcessorTest {
     hdfsSiteProperties.put("dfs.namenode.rpc-address." + expectedNameService + "." + expectedNodeOne, expectedHostName + ":" + expectedPortNum);
     hdfsSiteProperties.put("dfs.namenode.rpc-address." + expectedNameService + "." + expectedNodeTwo, expectedHostName + ":" + expectedPortNum);
 
-
     BlueprintConfigurationProcessor configProcessor =
       new BlueprintConfigurationProcessor(configProperties);
 
@@ -1178,6 +1184,52 @@ public class BlueprintConfigurationProcessorTest {
 
   }
 
+  @Test
+  public void testDoNameNodeHighAvailabilityUpdateWithHAEnabledNameServicePropertiesIncluded() throws Exception {
+    final String expectedNameService = "mynameservice";
+    final String expectedHostName = "c6401.apache.ambari.org";
+
+    EasyMockSupport mockSupport = new EasyMockSupport();
+
+    HostGroup mockHostGroupOne = mockSupport.createMock(HostGroup.class);
+
+    expect(mockHostGroupOne.getHostInfo()).andReturn(Arrays.asList(expectedHostName, "serverTwo")).atLeastOnce();
+
+    mockSupport.replayAll();
+
+    Map<String, Map<String, String>> configProperties =
+      new HashMap<String, Map<String, String>>();
+
+    Map<String, String> coreSiteProperties =
+      new HashMap<String, String>();
+    Map<String, String> hbaseSiteProperties =
+      new HashMap<String, String>();
+
+
+    configProperties.put("core-site", coreSiteProperties);
+    configProperties.put("hbase-site", hbaseSiteProperties);
+
+    // configure fs.defaultFS to include a nameservice name, rather than a host name
+    coreSiteProperties.put("fs.defaultFS", "hdfs://" + expectedNameService);
+    // configure hbase.rootdir to include a nameservice name, rather than a host name
+    hbaseSiteProperties.put("hbase.rootdir", "hdfs://" + expectedNameService + "/apps/hbase/data");
+
+    BlueprintConfigurationProcessor configProcessor =
+      new BlueprintConfigurationProcessor(configProperties);
+
+    // call top-level export method, which will call the HA-specific method if HA is enabled
+    configProcessor.doUpdateForBlueprintExport(Arrays.asList(mockHostGroupOne));
+
+    // verify that any properties that include nameservices are not removed from the exported blueprint's configuration
+    assertEquals("Property containing an HA nameservice (fs.defaultFS), was not correctly exported by the processor",
+      "hdfs://" + expectedNameService, coreSiteProperties.get("fs.defaultFS"));
+    assertEquals("Property containing an HA nameservice (hbase.rootdir), was not correctly exported by the processor",
+      "hdfs://" + expectedNameService + "/apps/hbase/data", hbaseSiteProperties.get("hbase.rootdir"));
+
+    mockSupport.verifyAll();
+
+  }
+
   @Test
   public void testDoNameNodeHighAvailabilityUpdateWithHANotEnabled() throws Exception {
     EasyMockSupport mockSupport = new EasyMockSupport();