KB 316823 - How to Change Default IB Interface in NVIDIA UFM (e.g., from ib0 to ib1)

By default, NVIDIA UFM binds to the ib0 InfiniBand interface during startup. If ib0 is down or unavailable, UFM will fail to start. In such cases, you may need to change the default interface to ib1 (or any other available IB interface).

This article guides you through the steps to change the default IB interface by editing the gv.cfg configuration file.

Location of Configuration File

The IB interface UFM uses is defined in the file:


/opt/ufm/conf/gv.cfg

Prerequisites

Root or sudo access to the server.
UFM must be stopped before making changes.

Verify that ib1 is up and operational:
```
ip link show ib1
```

Steps to Change IB Interface

Stop UFM Service:
```
sudo systemctl stop ufm
```
Edit gv.cfg Configuration File:
Open the file in a text editor:
```
sudo nano /opt/ufm/conf/gv.cfg
```
Locate the Following Line:
```
ib_interface=ib0
```
Change ib0 to ib1:
Modify the line as follows:
```
ib_interface=ib1
```
Save and Exit the editor (For nano, press Ctrl + O, Enter, then Ctrl + X).
Start UFM Service:
```
sudo systemctl start ufm
```

Verification

To ensure UFM is using the new interface:

Check UFM status:
```
sudo systemctl status ufm
```

Review UFM logs for interface bindings:

sudo tail -f /opt/ufm/files/logs/ibdiagnet.log

Confirm the IB interface is active and connected:
```
ibstat ib1
```

Troubleshooting

If ib1 is also down, UFM will not start. Ensure the interface is physically connected and active.
Double-check that you edited the correct line in gv.cfg.
Run ibdiagnet manually to test interface functionality.

Notes

Changing the IB interface does not persist across interface renaming or re-indexing (e.g., after firmware or OS updates). Always verify the IB device name.
It's recommended to maintain consistent naming using udev rules if your environment has multiple IB interfaces.