Virtual PROOF cluster

Dear all

Is there anyone who has experience of constructing a PROOF cluster using Virtual nodes only?

I was trying to construct such cluster and encountered some troubles.

Here is a brief summary of what I did

  1. I first prepared a Virtual master node on which the root package, xproofd, xrootd and PoD have been properly installed (This was a Ubuntu VirtualBox VM)

  2. I then opened another VirtualBox VM which is a CERN VM. I started a ROOT session and use the usual TProof instance to connect to the node in #1

  3. I ended up with the situation described by the following figure
    (left: Ubuntu VirtualBox VM (PROOF Master), right: CERN VM VirtualBox )
    (Both virtual machines were installed on the same physical PC)

I encountered the same problem when setting up a PROOF cluster with several physical machines.

I ended up with

151231 10:18:47 001 Proofx-E: Conn::Connect: failed to connect to proof://changhengfai11@ubuntu:21001//
151231 10:18:47 001 Proofx-E: XrdProofConn: XrdProofConn: severe error occurred while opening a connection to server [ubuntu:21001]

when opening a connection to the PROOF master

Any idea?

Is this problem related to network configuration or permission issue?


This looks more as a network problem … is port 21001 open to client machine?
Can you check if you have any evidence of the connection attempt on the master xproofd log? It should be located somewhere in the POD directory, something like


G Ganis