YARN-6069. CORS support in timeline v2 (Rohith Sharma K S via Varun Saxena)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml

@@ -3068,4 +3068,15 @@
     <value>64</value>
   </property>
 
+  <property>
+    <description>
+      Flag to enable cross-origin (CORS) support for timeline service v1.x or
+      Timeline Reader in timeline service v2. For timeline service v2, also add
+      org.apache.hadoop.security.HttpCrossOriginFilterInitializer to the
+      configuration hadoop.http.filter.initializers in core-site.xml.
+    </description>
+    <name>yarn.timeline-service.http-cross-origin.enabled</name>
+    <value>false</value>
+  </property>
+
 </configuration>

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-timelineservice/src/main/java/org/apache/hadoop/yarn/server/timelineservice/reader/TimelineReaderServer.java

@@ -32,6 +32,7 @@ import org.apache.hadoop.classification.InterfaceStability.Unstable;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.http.HttpServer2;
 import org.apache.hadoop.http.lib.StaticUserWebFilter;
+import org.apache.hadoop.security.HttpCrossOriginFilterInitializer;
 import org.apache.hadoop.service.CompositeService;
 import org.apache.hadoop.util.ExitUtil;
 import org.apache.hadoop.util.ReflectionUtils;
@@ -134,6 +135,14 @@ public class TimelineReaderServer extends CompositeService {
         YarnConfiguration.TIMELINE_SERVICE_BIND_HOST,
         WebAppUtils.getTimelineReaderWebAppURL(conf));
     LOG.info("Instantiating TimelineReaderWebApp at " + bindAddress);
+    boolean enableCorsFilter = conf.getBoolean(
+        YarnConfiguration.TIMELINE_SERVICE_HTTP_CROSS_ORIGIN_ENABLED,
+        YarnConfiguration.TIMELINE_SERVICE_HTTP_CROSS_ORIGIN_ENABLED_DEFAULT);
+    // setup CORS
+    if (enableCorsFilter) {
+      conf.setBoolean(HttpCrossOriginFilterInitializer.PREFIX
+          + HttpCrossOriginFilterInitializer.ENABLED_SUFFIX, true);
+    }
     try {
       HttpServer2.Builder builder = new HttpServer2.Builder()
             .setName("timeline")

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/TimelineServiceV2.md

@@ -142,6 +142,15 @@ New configuration parameters that are introduced with v.2 are marked bold.
 | **`yarn.timeline-service.hbase.coprocessor.app-final-value-retention-milliseconds`** | The setting that controls how long the final value of a metric of a completed app is retained before merging into the flow sum. Defaults to `259200000` (3 days). This should be set in the HBase cluster. |
 | **`yarn.rm.system-metrics-publisher.emit-container-events`** | The setting that controls whether yarn container metrics is published to the timeline server or not by RM. This configuration setting is for ATS V2. Defaults to `false`. |
 
+#### Enabling CORS support
+To enable cross-origin support (CORS) for the Timeline Service v.2, please set the following configuration parameters:
+
+In yarn-site.xml, set yarn.timeline-service.http-cross-origin.enabled to true.
+
+In core-site.xml, add org.apache.hadoop.security.HttpCrossOriginFilterInitializer to hadoop.http.filter.initializers.
+
+For more configurations used for cross-origin support, refer to [HttpAuthentication](../../hadoop-project-dist/hadoop-common/HttpAuthentication.html#CORS). Please note that yarn.timeline-service.http-cross-origin.enabled, if set to true, overrides hadoop.http.cross-origin.enabled.
+
 
 
 ### <a name="Enabling_Timeline_Service_v2"></a>Enabling Timeline Service v.2