Force Consistency Check??

Question

I'm trying to create a VPC between two 5ks to a single server but when I bring them up the VPC never changes from the down state.... Below shows the config of each and some show commands. It seems like 5k2 hasn't performed a consistency check but 5k1 has and it shows successful.
5k1
int eth 1/12
channel-group 204 mode active
interface port-channel204
  switchport access vlan 1072
  speed 10000
  vpc 204
5k1# show port-channel summary
Flags:  D - Down        P - Up in port-channel (members)
        I - Individual  H - Hot-standby (LACP only)
        s - Suspended   r - Module-removed
        S - Switched    R - Routed
        U - Up (port-channel)
        M - Not in use. Min-links not met
Group Port-       Type     Protocol  Member Ports
      Channel
1     Po1(SU)     Eth      NONE      Eth1/31(P) 
204   Po204(SD)   Eth      LACP      Eth1/12(I)
5k1# show vpc br
Legend:
                (*) - local vPC is down, forwarding via vPC peer-link
vPC domain id                   : 5  
Peer status                     : peer adjacency formed ok     
vPC keep-alive status           : peer is alive                
Configuration consistency status: success
Per-vlan consistency status     : success                      
Type-2 consistency status       : success
vPC role                        : secondary                    
Number of vPCs configured       : 9  
Peer Gateway                    : Disabled
Dual-active excluded VLANs      : -
Graceful Consistency Check      : Enabled
vPC Peer-link status
id   Port   Status Active vlans   
1    Po1    up     1-9,33,36,43,46,329,1050-1059,1070,1072-1073,1101-       
                   1116,1997                                                
vPC status
id     Port        Status Consistency Reason                     Active vlans
204    Po204       down*  success     success                    -          
5k2
5k2# show run int port 204
!Command: show running-config interface port-channel204
!Time: Tue Dec 17 09:35:46 2013
version 5.1(3)N1(1a)
interface port-channel204
  switchport access vlan 1072
  speed 10000
  vpc 204
interface Ethernet1/12
  channel-group 204 mode active
5k2# show port-channel summary
Flags:  D - Down        P - Up in port-channel (members)
        I - Individual  H - Hot-standby (LACP only)
        s - Suspended   r - Module-removed
        S - Switched    R - Routed
        U - Up (port-channel)
        M - Not in use. Min-links not met
Group Port-       Type     Protocol  Member Ports
      Channel
1     Po1(SU)     Eth      NONE      Eth1/32(P)  
204   Po204(SD)   Eth      LACP      Eth1/12(I)  
5k2# show vpc brief
Legend:
                (*) - local vPC is down, forwarding via vPC peer-link
vPC domain id                   : 5  
Peer status                     : peer adjacency formed ok     
vPC keep-alive status           : peer is alive                
Configuration consistency status: success
Per-vlan consistency status     : success                      
Type-2 consistency status       : success
vPC role                        : primary                      
Number of vPCs configured       : 41 
Peer Gateway                    : Disabled
Dual-active excluded VLANs      : -
Graceful Consistency Check      : Enabled
vPC Peer-link status
id   Port   Status Active vlans   
1    Po1    up     1-9,33,36,43,46,329,1050-1059,1070,1072-1073,1101-       
                   1116,1997                                                
vPC status
id     Port        Status Consistency Reason                     Active vlans
204    Po204       down*  Not         Consistency Check Not      -          
                          Applicable  Performed                             

Answer 1

Hi Justin,
The Link Aggregate you've configured is what's referred to as dynamic, and as such it will use the Link Aggregation Control Protocol (LACP) to negotiate with the link partner i.e., the server, on a number of parameters to use for the forming and control of the aggregate.
What we can see from the show port-channel summary command is that the links are in the Individual (I) state. This is usually an indication that the remote device is not sending LACPDU frames. You should be able to see this by checking the Recv column in the output of show lacp counters interface port-channel 204 command. It will most likely be 0.
If that's the case you'll need to check with the server guys how they have the aggregate configured. It must be using NIC teaming software supporting something along the lines of IEEE 802.3ad Dynamic (HP), IEEE 802.3ad or mode=4 (Linux) or LACP with VMware ESXi.
If you're connecting to a server whose OS only supports static link aggregation e.g., VMware ESXi prior to version 5.1, then you should change the Nexus configuration to use static Link Aggregation with the channel-group 204 mode on command under the Ethernet1/12 interface. Note that you can't change the keywords used with the channel-group command, but have to remove it and add it back using the on keyword.
Regards