Nexus Reload peer-link do not come up

[jcarvalh]

Hello,

I am doing some tests with 2 Nexus 7010 and I got the following behaviour

1- put peer-keepalive down (all continues to work)

2- after I put peer-link down (both switch become primary)

3- after I put peer-link up (all back to normal)

4- after I put peer-link down again (split brain)

5- then I reload one of the VDC and connect peer-link during reload (reloaded switch does not form peer with neighbor unless I connect peer-keepalive; after 6 minutes it will start working as primary since I have auto recovery configured)

Is this the normal behaviour? Do I need peer-keepalive at startup? What I find odd is that I do not peer-keepalive for step 3 (reconnecting peer-link without keepalive)

Can't find any doc with explanation for this behaviour.

Any help is appreciated.

Thanks and regards.

Joao

[Mark Malone]

Hi Joao

Yes if the keep-alives is not in place peer-link will not come back up, peer-link will stay up without keep-alives once it was there to begin with but if you take it down and reboot peer-link will stay down , that's why its best practice to have it in place with peer-link , always have the keep-alives in place

theres 3 ways to do it as best practice I went through it with TAC before in our DC I will try find the doc they sent me ,using the mgmt. I think was preferred first if possible

EDIT:Found one of the dosc we were supplied page 30

http://www.cisco.com/c/dam/en/us/td/docs/switches/datacenter/sw/design/vpc_design/vpc_best_practices_design_guide.pdf

Strong Recommendations: When building a vPC peer-keepalive link, use the following in descending order of preference:

1. Dedicated link(s) (1-Gigabit Ethernet port is enough) configured as L3. Port-channel with 2 X 1G port is even better.
2. Mgmt0 interface (along with management traffic)
3. As a last resort, route the peer-keepalive link over the Layer 3 infrastructure

WARNING: Do not configure vPC peer-keepalive link on top of vPC peer-link; peer-keepalive messages must not be carried over vPC peer-link to avoid fate sharing in case peer-link goes down