Fixing "Error from osm_opensm_bind (0x2B) Perhaps another instance of OpenSM is already running"

Sometimes, OpenSM service won't start automatically or restart  it will fail:

OpenSM 3.3.11 UMAD 

Entering DISCOVERING state 


Error from osm_opensm_bind (0x2B)
Perhaps another instance of OpenSM is already running
Exiting SM 

First thing we want to confirm is that the card currently in IB mode:

	CA 'ibv_device0'
	CA type:
	Number of ports: 1
	Firmware version: 2.42.5000
	Hardware version: 0x0
	Node GUID: 0x0002c903000232da
	System image GUID: 0x0002c903000232dd
	Port 1:
	State: Initializing
	Physical state: LinkUp
	Rate: 56
	Base lid: 1
	LMC: 0
	SM lid: 1
	Capability mask: 0x90580000
	Port GUID: 0x0002c903000232db
	Link layer: IB
	Transport: IB

view raw sudo ibstat hosted with ❤ by GitHub

Then, opensm.conf has to be adjusted. By default its first option, GUID, is empty. Take GUID of an active port (port 1 or port 2, 0x0002c903000232db in the example) and replace the following line:

	#
	# DEVICE ATTRIBUTES OPTIONS
	#
	# The port GUID on which the OpenSM is running
	guid 0x0000000000000000

view raw C:\Program Files\OFED\OpenSM\opensm.conf hosted with ❤ by GitHub

Done, service should start as expected.