Enable Cross-Origin Support on YARN

You must enable Cross-Origin Resource Sharing (CORS) on YARN such that the corresponding services accept cross-origin requests from only selected domains. Enabling CORS also helps the YARN UI fetch data endpoints from the browser.

1. In Ambari Web, browse to Services > HDFS > Configs, then expand Advanced core-site.
2. Add the value org.apache.hadoop.security.HttpCrossOriginFilterInitializer to the existing set of values configured for the hadoop.http.filter.initializers property.
3. Configure values for the following properties depending on your requirements:

   Property	Description
   hadoop.http.cross-origin.allowed-headers	Comma-separated list of headers allowed for cross-origin support. The default values are X-Requested-With, Content-Type, Accept, Origin, WWW-Authenticate, Accept-Encoding, and Transfer-Encoding.
   hadoop.http.cross-origin.allowed-origins	Comma-separated list of origins allowed for cross-origin support. The default value is *. Mention only specific origins so that the services do not accept all the cross-origin requests.
   hadoop.http.cross-origin.allowed-methods	Comma-separated list of methods allowed for cross-origin support. The default values are GET, PUT, POST, OPTIONS, HEAD, and DELETE.
   hadoop.http.cross-origin.max-age	Number of seconds until when a preflight request can be cached. The default value is 1800 seconds.

4. Click Save.
5. Add a description of the modified HDFS configuration and click Save.
6. In Ambari Web, browse to Services > YARN > Configs, then expand Advanced yarn-site.
7. Configure values for the following properties depending on your requirements:

   Property	Description
   yarn.nodemanager.webapp.cross-origin.enabled	Enable cross-origin support for the NodeManager. The default value is true.
   yarn.resourcemanager.webapp.cross-origin.enabled	Enable cross-origin support for the ResourceManager. The default value is true.
   yarn.timeline-service.http-cross-origin.enabled	Enable cross-origin support for the timeline service. The default value is true.

   	Note
   	The value of the hadoop.http.cross-origin.allowed-origins property in yarn-site.xml overrides the value of the same property in core-site.xml. You can configure the value of this property to allow access to specific domains; for example, regex:.*[.]hwx[.]site(:\d*)?.

8. Click Save.
9. Add a description of the modified YARN configuration and click Save.
10. Restart the HDFS and YARN services.