[rancid] Nexus 1000v switch-router

[heasley]

Thu, Jun 30, 2016 at 04:59:05PM +0000, Charles T. Brooks:
> When you use device-type cisco with an NX-os device like a Nexus switch, each time a port is assigned you will get a great deal of spurious output.  This is because the NX-os devices report VLAN configurations like this:
> 
> 
> VLAN Name                             Status    Ports
> ---- -------------------------------- --------- -------------------------------
> 1    default                          active
> 100  VLAN0100                         active    Po3, Po4, Po5, Po6, Po7, Po8
>                                                 Veth1, Veth2, Veth4, Veth7
>                                                 Veth9, Veth10, Veth13, Veth14
>                                                 Veth15, Veth16, Veth17, Veth18
>                                                 Veth21, Veth22, Veth23, Veth24
>                                                 Veth25, Veth26, Veth29, Veth30
>                                                 (etc. to arbitrary number of ports)
> 
> If, in the example above, I delete virtual ethernet port #2 (Veth2) it will cause changes in roughly 24 lines, because NX-os will rejigger every single line for this vlan by "bumping up" the ports into the four-ports per line form.  Does that make sense?  Anyway, somebody moves one or two ports, and instead of getting the actual one or two line config change I get 40 or fifty lines of noise emailed to all the netadmins.

ios does the same thing and the same format on 6500/etc.  rancid mostly just
takes the output of the commands as-is.

> The cisco-nx device type addresses this problem (although frankly I don't know how;  I suspect it just doesn't do a "show vlan" command).

the command is there; see etc/rancid.types.base or rancid -t cisco-nx -C
but it is not reformatting or filtering in any special manner, so the
behavior should be the same.