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UCS MGMT0 and Nexus 7k

So I am currently bringing up a new UCS cluster and having connectivity issues after the initial configuration. These are 6120s cabled to a Nexus 7k. All signs on the Fabric Interconnects look good and the group managing the Nexus 7k say it is configured properly and of course we have triple checked physical connectivity. In our other deployments we usually have the MGMT ports connecting to a separate catalyst 4948 so in the absense of anything else my mind is jumping on this configuration change. I haven't found anything that says don't cable your MGMT to a Nexus but I am wondering if any one can think of a technical issue that would prevent the MGMT network to work while cabled to a Nexus rather than a traditional switch?


Everyone's tags (3)
Cisco Employee

UCS MGMT0 and Nexus 7k

Going to ask the obvious, but have you configured the Mgmt0 1G Interface as an Access port on the N7K?  There's no trunking on the Mgmt0 interface of the 6100. 

Does the port come up on the N7K? 




UCS MGMT0 and Nexus 7k

Yes the port shows as connected on the N7k side and I am taking it at the trust of the group that configured it that it is configured as an access port. And just to get it out of the way, MTU, duplex and speed have all been confirmed on the link on the Nexus side as well.

I appreciate all comments even those considered obvious so thanks Robert.

Cisco Employee

UCS MGMT0 and Nexus 7k

Don't "trust" anyone

Can you get the switch interface config from the N7K where UCS Mgmt0 connects?  Please post it here.

An easy test, is get your N7K guys to setup an SVI on the N7K for the VLAN used for UCS management (rather than rely on pinging the default gateway).  If you can't ping this SVI address from the UCS CLI (local-management), then your problem is isolated to either one of these devices.  Could just be the management VLAN for UCS hasn't been created or trunked between your N7K and upstream network somewhere...

From the UCS CLI can you also plaste the output of:

show cluster state




UCS MGMT0 and Nexus 7k

Got the port config and it is setup in access mode. Also confirmed the VLAN is created on the switch. I am still investigating the possibility of it not being configured for the upstream connections

Eth2/16       119     eth  access up      none                       1000(D) --

Ethernet2/16 is up

  Hardware: 10/100/1000 Ethernet, address: 30e4.db0c.a53b (bia 30e4.db0c.a53b)

  Description: UCS_mgmt

  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec

  reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA

  Port mode is access

  full-duplex, 1000 Mb/s

  Beacon is turned off

  Auto-Negotiation is turned on

  Input flow-control is off, output flow-control is off

  Auto-mdix is turned on

  Switchport monitor is off

  EtherType is 0x8100

  Last link flapped 2d12h

  Last clearing of "show interface" counters never

  30 seconds input rate 0 bits/sec, 0 packets/sec

  30 seconds output rate 528 bits/sec, 0 packets/sec

  Load-Interval #2: 5 minute (300 seconds)

    input rate 0 bps, 0 pps; output rate 520 bps, 0 pps


    20 unicast packets  0 multicast packets  17 broadcast packets

    37 input packets  2748 bytes

    0 jumbo packets  0 storm suppression packets

    0 runts  0 giants  0 CRC  0 no buffer

    0 input error  0 short frame  0 overrun   0 underrun  0 ignored

    0 watchdog  0 bad etype drop  0 bad proto drop  0 if down drop

    0 input with dribble  0 input discard

    0 Rx pause


    24 unicast packets  120157 multicast packets  38 broadcast packets

    120219 output packets  16447099 bytes

    0 jumbo packets

    0 output error  0 collision  0 deferred  0 late collision

    0 lost carrier  0 no carrier  0 babble  0 output discard

    0 Tx pause

  5 interface resets

Cisco Employee

UCS MGMT0 and Nexus 7k

Thanks Kevin.

I'd do the SVI ping test next.  That will tell you if youi're problem is on UCS or northbound of your N7Ks.


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