So what I have found outside of bright cluster (BBC - as in I had this kind of issue under ubuntu in my cluster Before Bright Cl;uster) is that you need to pay attention to the drivers that support your version of the card.
I would start by logging in via SSH and running the following
lspci | grep Mellanox
you should find something like the following
08:00.0 InfiniBand: Mellanox Technologies MT26418 [ConnectX VPI PCIe 2.0 5GT/s - IB DDR / 10GigE] (rev b0)
At which point you can determine which version of the OFED drivers support your card. Old version such as MellanoX-2 are not supported in current drivers.
Current cards support matrix https://www.mellanox.com/support/mlnx-ofed-matrix159
for older cards you will need to use an older mellanox driver (which maybe unsupported in BC)
I would work out how to stand up linux on a node with a working driver and then determine how to get that into the BC node deployment.