The NVSwitch-detection fix (983f41a) was necessary but not sufficient on
HGX B200 (Kaytus KR9288-X3): ExecCondition now correctly runs fabricmanager,
but nvidia-fabricmanager-start.sh then aborts with "Kernel module ib_umad
has not been loaded" on this NVL5+ board, leaving the fabric stuck in
"In Progress" and cascading into failed dcgmi diag/NVBandwidth/NCCL/Validate
GPU SAT tasks (confirmed via support bundle 20260729-165331).
Neither nvidia-fabricmanager nor DCGM declare the NVLink5 support packages
as apt dependencies (checked against the cuda-repo Packages index directly):
ib_umad must be modprobed before FM starts, nvlsm (InfiniBand Subnet Manager)
is launched internally by FM's own start script once present, and DCGM
dlopens libnvidia-nscq at runtime for NVSwitch health monitoring.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
