HDDS-107. TestOzoneConfigurationFields is failing.

Contributed by LiXin Ge & Mukul Kumar Singh.

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/conf/HddsConfServlet.java

@@ -39,6 +39,8 @@ import com.google.common.annotations.VisibleForTesting;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static org.apache.hadoop.ozone.OzoneConfigKeys.OZONE_TAGS_SYSTEM_KEY;
+
 /**
  * A servlet to print out the running configuration data.
  */
@@ -154,7 +156,8 @@ public class HddsConfServlet extends HttpServlet {
 
     switch (cmd) {
     case "getOzoneTags":
-      out.write(gson.toJson(config.get("ozone.tags.system").split(",")));
+      out.write(gson.toJson(config.get(OZONE_TAGS_SYSTEM_KEY)
+          .split(",")));
       break;
     case "getPropertyByTag":
       String tags = request.getParameter("tags");

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

@@ -31,6 +31,8 @@ import org.apache.ratis.util.TimeDuration;
 @InterfaceAudience.Public
 @InterfaceStability.Unstable
 public final class OzoneConfigKeys {
+  public static final String OZONE_TAGS_SYSTEM_KEY =
+      "ozone.tags.system";
   public static final String DFS_CONTAINER_IPC_PORT =
       "dfs.container.ipc";
   public static final int DFS_CONTAINER_IPC_PORT_DEFAULT = 9859;

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/TestOzoneConfigurationFields.java

@@ -34,5 +34,6 @@ public class TestOzoneConfigurationFields extends TestConfigurationFieldsBase {
             KSMConfigKeys.class};
     errorIfMissingConfigProps = true;
     errorIfMissingXmlProps = true;
+    xmlPropsToSkipCompare.add("hadoop.tags.custom");
   }
 }