Hi,
There's some SNMP monitoring of the FEX via the CISCO-ETHERNET-FABRIC-EXTENDER-MIB, but looking through the response from a Nexus 5000 running NX-OS version 5.1(3)N2(1) I don't see anything that gives a simple "online" or "offline" as you get from the show fex command from the switch CLI.
It's not particularly elegent, but one option might be to monitor the CISCO-ENTITY-FRU-CONTROL-MIB.
In the following you can see I have two FEX, numbered 101 and 102, both of which are online.
ocs5548-2# sh fex
FEX FEX FEX FEX
Number Description State Model Serial
------------------------------------------------------------------------
101 FEX0101 Online N2K-C2232PP-10GE SSI155001QZ
102 FEX0102 Online N2K-C2232PP-10GE SSI15460AT7
When I browse the cefcModuleTable from this MIB I can see the two FEX, numbered 101000022 and 102000022, with an AdminStatus of enabled and an OperStatus of ok.
[sfuller@rhel8 ~]$ snmpwalk ocs5548-2 cefcMIBObjects.2
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleAdminStatus.22 = INTEGER: enabled(1)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleAdminStatus.24 = INTEGER: enabled(1)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleAdminStatus.101000022 = INTEGER: enabled(1)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleAdminStatus.102000022 = INTEGER: enabled(1)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleOperStatus.22 = INTEGER: ok(2)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleOperStatus.24 = INTEGER: ok(2)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleOperStatus.101000022 = INTEGER: ok(2)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleOperStatus.102000022 = INTEGER: ok(2)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleResetReason.22 = INTEGER: 0
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleResetReason.24 = INTEGER: 0
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleResetReason.101000022 = INTEGER: 0
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleResetReason.102000022 = INTEGER: 0
If I then take one of the FEX offline (by shutting the port-channel on the Nexus) I can see the FEX offline from the CLI as expected:
ocs5548-2(config-if)# sh fex
FEX FEX FEX FEX
Number Description State Model Serial
------------------------------------------------------------------------
101 FEX0101 Offline N2K-C2232PP-10GE SSI155001QZ
102 FEX0102 Online N2K-C2232PP-10GE SSI15460AT7
And the entry in the cefcModuleTable has now been removed.
[sfuller@rhel8 ~]$ snmpwalk ocs5548-2 cefcMIBObjects.2
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleAdminStatus.22 = INTEGER: enabled(1)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleAdminStatus.24 = INTEGER: enabled(1)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleAdminStatus.102000022 = INTEGER: enabled(1)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleOperStatus.22 = INTEGER: ok(2)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleOperStatus.24 = INTEGER: ok(2)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleOperStatus.102000022 = INTEGER: ok(2)
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleResetReason.22 = INTEGER: 0
CISCO-ENTITY-FRU-CONTROL-MIB::cefcModuleResetReason.24 = INTEGER: 0
As I say, it's not elegant or great, but perhaps with a little messing around and a little more NMS knowledge than I have, you might be able to put together something that gives you what you need.
It might also be worth raising a question in the Network Management Support Community as there may be someone following that community with more experience.
Regards
