Prometheus installation - only one node is visible

I’ve installed the Prometheus stack from the Rancher catalog (I’m running Rancher 2.1.4) with all default settings to see how it works. Problem is, I’m able to monitor only one node, the node where prometheus-server is running… Looks like its not collecting data from the other nodes…
As this was a default install I thought maybe somebody had the same experience?
Thank you