How to keep active switch of Stackwise Virtual

[DaeHeon Kang]

Hi

I've set Stackwise Virtual with different priority value(each 15 and 14) for aiming to keep one switch always-be active. 

The switch that I set priority 15 didn't become active when I later turned it on after first booting the switch with priority 14

as the below show output.

I expected the switch that has 15 priority should be active switch regardless the order of booting. 

What could cause this? And additionally, is there any command for changing over active/standby swith?

==========================================================

AAA#show switch
Switch/Stack Mac Address : 0cd0.f83b.7e00 - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
-------------------------------------------------------------------------------------
1 Standby 0cd0.f83b.5300 15 V01 Ready
*2 Active 0cd0.f83b.7e00 14 V01 Ready

[balaji.bandi]

Look at some FAQ as below :

Q Does StackWise Virtual support the SSO role preemption feature?

ANo. The SSO role selection is determined during the initial bootup process of both switches. If the SSO active switch is already in an operational state, then the other stack member will boot up in the HOT_STANDBY switch independent of its switch ID, priority, or MAC address parameters. 

 Q What are Cisco recommended best practices in building StackWise Virtual domain configuration?

A Following are recommended Cisco StackWise Virtual best practices:• StackWise Virtual domain ID: Use any range from 1 through 255. No conflict in network.• Switch ID: Supported range is 1 through 9. Renumber if needed to start in ascending number.• Switch priority: Default is 1. Recommended to increase priority for specific stack member if prefer to boot up in ACTIVE role.• Stack MAC address: Default is infinite. Recommended to keep default settings

https://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-3850-series-switches/q-and-a-c67-738577.pdf

[Tony T.]

Hey-

I was reading through the white papers on stackwise virtual and I couldn't find anything that mentions why the interface nomenclature doesn't change once you apply the "redundancy force-switchover" command. Meaning, once the standby switch becomes the primary (switch 1) after implementing the command above, the interfaces don't switch. Example:

Before Force-Switchover command:

Switch1# Fa1/0/1

Switch2# Fa2/0/1

After Force-Switchover command:

Switch1# Fa2/0/1

Switch2# Fa1/0/1

Thanks in advance for the assistance.

V/r,

Tony

[Reza Sharifi]

From the 9300 series Stackwise document:

StackWise Virtual does not support preemption capability to avoid unnecessary traffic disruption. If you need to change the StackWise Virtual role to another switch, the “redundancy force-switchover” command can be used for that purpose. This will move the active role to the other switch with very minimal traffic disruption.

link:

https://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-9000/nb-06-cat-9k-stack-wp-cte-en.pdf

HTH

[Tony T.]

Thank you, Reza.

I saw the same paragraph in the white paper. However, when I administer the command "redundancy force-switchover" the interfaces remain the same on both nodes. If I'm not understanding what Cisco means by preemption I apologize. Let me know if my original question makes sense?

Tony

[paul driver]

Hello

the stack isn’t preemptive so if you boot the switch with the higher priority after a switch with a lower value then it will not preempt and become the master - in the 3850-2960x you have around a 20 sec window for master election to take place so in theory you could have the least priority value switch becoming the master of that powered on and booted first before any other member switch 

[Tony T.]

Thanks, Paul.

I appreciate the explanation. However, what's confusing me is after both nodes (9600's) bootup and I have a active and standby node. I then perform the "redundancy force-switchover" command. So the node that was standby is now active. Unfortunately, the standby node kept the same interface nomenclature as before the force switchover. So when folks are making changes to the configurations they are geting confused. Minor issue but frustrating.  

Thanks,

Tony

[tue.dybkjaer@skat.dk]

You can set the role of the switch using this command:
sw 2 role standby
or
sw 1 role active