YARN-8652. [UI2] YARN UI2 breaks if getUserInfo REST API is not available in older versions. Contributed by Akhil PB.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-ui/src/main/webapp/app/controllers/application.js

@@ -65,6 +65,9 @@ export default Ember.Controller.extend({
   }.property('model.clusterInfo'),
 
   userInfo: function() {
-    return this.model.userInfo.get('firstObject');
+    if (this.model.userInfo) {
+      return this.model.userInfo.get('firstObject');
+    }
+    return null;
   }.property('model.userInfo'),
 });

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-ui/src/main/webapp/app/routes/application.js

@@ -23,7 +23,9 @@ export default AbstractRoute.extend({
   model() {
     return Ember.RSVP.hash({
       clusterInfo: this.store.findAll('ClusterInfo', {reload: true}),
-      userInfo: this.store.findAll('cluster-user-info', {reload: true})
+      userInfo: this.store.findAll('cluster-user-info', {reload: true}).catch(function() {
+        return null;
+      })
     });
   },