Configure CORSedit

If APM Server is deployed in an origin different than the page’s origin, you will need to configure Cross-Origin Resource Sharing (CORS).

A list of permitted origins can be supplied to the apm-server.rum.allow_origins configuration option. By default, APM Server allows all origins.

How CORS worksedit

When the RUM agent makes its initial POST request, the browser will check to see if it is a cross-origin request. If it is, the browser automatically makes a preflight OPTIONS request to the server to ensure the original POST request is allowed. If this OPTIONS check passes, then the original POST request is allowed. This request will fail if RUM support is not configured in the APM Server.

If you use a proxy, the preflight request headers may be necessary for your configuration:

Access-Control-Request-Headers: Content-Type
Access-Control-Request-Method: POST
Origin: [request-origin]

The response should include these headers:

Access-Control-Allow-Headers: Content-Type
Access-Control-Allow-Methods: POST, OPTIONS
Access-Control-Allow-Origin: [request-origin]

To learn more about CORS, see the MDN page on Cross-Origin Resource Sharing.