Register to R Server to R cluster

Hi, I have setup an OPAL server at and have register an R/ROCK server at the same address. I can run some FedAna analysis on this single server. I have now installed a second server https://srv2.stats-con with relevant software and as of now NGinx, OPAL, and R/Rock are running, ports are open…

How do I add the SRV2 server to the server cluster (currently only localhost:8085) which I have registered at

Thanks, Wilmar


Go to Administration/Apps and follow the Discovery instructions:

Regards Yannick

Dear Yannick,

thanks! I still could not add srv2 to the R Server cluster. I did:

  1. I set admin and password in explicitly on both servers, ie and rock.default.administrator.username=abcd
  2. I set the same self-registration key on and
  3. I added an R server (administrator) with OPAL GUI on
  4. I press Apps Registry > Refresh on

However, the is not recognized.

I find it confusing where to set the admin and password since there is:

  1. OPAL:
  2. OPAL: shiro.ini
  3. ROCK: Rserv.conf
  4. ROCK: application.yml

What am I missing here?

OPAL and R are running on (but no MongoDB, no MySQL).

Kind regards,



Not sure of what you are trying to achieve: I understood as you talked about a “cluster” that you wanted to register the Rock server from srv2 into the Opal of srv1. Is that the case?



Step 1: As of now, I would like to create an R “default” cluster which includes srv1 (R server) and srv2 (R server) in the R cluster administered on srv1.

Step 2: Later I am planning adding different datasets to srv1 and srv2 and performing a federated analysis with DataSHIELD using different stored in Opal on srv1 and srv2 (distributed), which will require installing MySQL and MongoDB on srv2, too.

Am I on the right path here?

Best, Wilmar

Step 1: Opal and Rock are different applications, then what you must register in srv1’s opal ( is the address of srv2’s rock (???), not the one of srv2’s opal ( By the way, you are trying to share the Rock app between two Opals, which sounds a bit strange.

Step 2: What is the purpose of having both Mongodb and Mysql databases? only one database is “required”.


Thanks, how do I find out the address of srv2 rock server? does not work …

Well that depends on your network’s set up. Again I am not sure of the benefit of what you are trying to do: standard set up is one opal with one R server. If you need more computation power or different R profiles, then you can link this same opal to additional R servers. In addition to that, the R servers do not need to be exposed externally (for obvious security reasons): only the opal application needs a connection to it/them.