User GuidesInfiniBand PKey Lifecycle

InfiniBand Port GUID Discovery

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The InfiniBand Port GUID Discovery workflow reads port GUIDs from UFM and writes them onto the matching Nautobot interfaces (custom_fields.ib_guid). Run it to populate ib_guid before workflows that consume it, such as IB PKey Member Add in By-Interfaces mode.

GUIDs are written only onto compute-side interfaces — the host/GPU HCA ports. The InfiniBand switches you select are the topology anchor, not sync targets: each UFM port is matched to the switch port it connects to, and the GUID is written onto the compute interface cabled to that switch port in Nautobot. Switch-owned ports and inter-switch links are skipped; no switch interface is ever modified.

Cable topology comes from Nautobot rather than from UFM node descriptions, because compute-tray OS hostnames are not under Config Manager’s control.

The workflow is dry-run by default. A dry run computes the GUID-to-interface mappings and reports what it would change without writing anything. Clear the Dry run checkbox to apply the mappings.

Prerequisites

Before running, confirm:

  • UFM appliance modeled in Nautobot. The device must have role UFM, a primary IP, and belong to the site you select. The UFM Device dropdown only lists devices with role UFM in the chosen site.
  • Switch devices modeled. The InfiniBand switches whose ports you want to read must exist in Nautobot.
  • Cable topology modeled. Discovery walks Nautobot cables to map switch ports to compute interfaces. Interfaces with no modeled cable are skipped.
  • UFM credentials available. Same requirement as the other InfiniBand workflows.

Running the workflow

  1. Navigate to the Config Manager URL for your environment.
  2. Click the + in the top right and select IBPortGuidDiscoveryWorkflow.
  3. Fill in the form using the field reference below and submit.
FieldDescriptionRequired
SiteSite that scopes the device dropdowns.Yes
UFM DeviceUFM appliance to read port GUIDs from. Lists devices with role UFM in the selected site.Yes
Switch DevicesOne or more InfiniBand switches that anchor the topology. UFM ports are matched to these switches’ ports, and GUIDs are written to the compute interfaces cabled to them.Yes
Dry runCompute mappings without writing ib_guid. Checked by default. Clear it to apply.No

InfiniBand Port GUID Discovery workflow form

After submission, a status page shows the three execution stages.

Execution stages

The workflow runs three stages. No approval is required.

  1. resolve_ufm — Resolve UFM hostname and site from Nautobot.

    Looks up the selected UFM device and reads its primary IP and site. Fails fast if the device has no primary IP.

  2. discover — Fetch UFM ports and Nautobot topology and compute mappings.

    Reads port GUIDs from UFM and the cable topology for the selected switches, then builds a per-interface mapping for each compute port that connects to one of those switches. Ports owned by the switches and inter-switch links are dropped. Each mapping carries an action: set (interface has no ib_guid yet), update (replace a stale value), noop (already correct), or skip (no cabled compute interface to write to).

  3. sync — Write ib_guid on each resolved interface.

    For every actionable mapping, sets custom_fields.ib_guid on the interface. Honors the Dry run setting and reports applied, would_apply, and skipped counts.

Verifying outcomes

After the workflow reports success, confirm:

  • Dry run. Review the summary’s would_apply count and the per-interface mappings. Nothing is written to Nautobot.
  • Applied run. Confirm applied is non-zero, then open the affected interfaces in Nautobot and verify custom_fields.ib_guid holds 0x + 16 hex characters.

Common issues

The UFM Device dropdown is empty.

The dropdown lists only devices with role UFM in the selected site. Confirm the UFM appliance has role UFM, a primary IP, and is assigned to the chosen site (or one of its child locations).

resolve_ufm fails with “UFM device has no primary IP address set in Nautobot”.

Set a primary IP on the UFM device in Nautobot, then re-run.

No mappings are produced, or everything is skipped.

Discovery relies on modeled cables between the selected switches and their compute-side interfaces. Confirm the cable topology exists in Nautobot and that you selected the correct switch devices.