03-14-2016 12:01 PM - edited 03-05-2019 03:33 AM
Dear All,
We have Nexus 93128 switches running on vPC.
Recently , we have done a network up grataion activity , during that time Nexus-9K-1 switch was powered Off.
After completion of activity. VPC role is showing like below. What exactly should be done to change the functional role of nexus switches or what need to be done to bring back these nexus switches as they were initially. for eg ,..
Nexus-9K-1 was at primary role.
Nexus-9K-2 was at secondary role.
Nexus-9K-1# sh vpc role
vPC Role status
----------------------------------------------------
vPC role : primary, operational secondary
Dual Active Detection Status : 0
vPC system-mac : 00:21:02:de:c3:5f
vPC system-priority : 4096
vPC local system-mac : ef:78:24:e7:b7:78
vPC local role-priority : 1
Nexus-9K-1#
Nexus-9K-2# sh vpc role
vPC Role status
----------------------------------------------------
vPC role : secondary, operational primary
Dual Active Detection Status : 0
vPC system-mac : 00:21:02:de:c3:5f
vPC system-priority : 4096
vPC local system-mac : e1:2e:2a:5c:4d:3b
vPC local role-priority : 2
Nexus-9K-2#
Rgds
JN
Solved! Go to Solution.
03-15-2016 02:06 AM
Hi
in the running config there should be something like below , change the priority like hsrp higher wins to flip over the roles , both switches should be identical as there vpc paired so there's no real need to flip them back I would have though unless for consistency
switch A
vpc domain 200
role priority 150
system-priority 150
peer-keepalive destination 10.x.x.x source 10.x.x.x vrf heartbeat
delay restore 90
switch B
vpc domain 200
role priority 200
system-priority 150
peer-keepalive destination 10.x.x.x source 10.x.x.x vrf heartbeat
delay restore 90
03-14-2016 12:01 PM
please reply
03-15-2016 02:06 AM
Hi
in the running config there should be something like below , change the priority like hsrp higher wins to flip over the roles , both switches should be identical as there vpc paired so there's no real need to flip them back I would have though unless for consistency
switch A
vpc domain 200
role priority 150
system-priority 150
peer-keepalive destination 10.x.x.x source 10.x.x.x vrf heartbeat
delay restore 90
switch B
vpc domain 200
role priority 200
system-priority 150
peer-keepalive destination 10.x.x.x source 10.x.x.x vrf heartbeat
delay restore 90
06-16-2016 01:56 AM
Hello,
You still have not answered the initial question - how to force operational secondary Nexus device to become operational primary one? Reloading operational primary is out of the question.
02-01-2017 01:06 PM
From all the readings I've done, it looks there're only 2 -ugly- ways to achieve this:
1- reload the secondary switch (operational as primary) or
2- flap (shut/unshut) the peer link on the secondary switch (operational as primary) -I'm assuming role priorities are configured in the right manner
And yep, a short disruption is expected
Hope someone out there is aware of a third less harsh approach
Cheers
Ps: it even looks the 2nd method is not an option (NOS5.x)! http://www.cisco.com/c/en/us/products/collateral/switches/nexus-5000-series-switches/design_guide_c07-625857.html#_Toc271759447, mentions that if the keepalive link doesn't go down, the role won't change! But bringing keep alive along with the peer link will cause a split brain condition, so it looks option 1 is the only safe option
10-25-2017 09:50 AM
If you are running ver 7 code there is this:
Complete these steps to enable hitless vPC role change.
• Ensure that the vPC feature is enabled.
• Ensure that the vPC peer link is up
• Verify the role priority of devices
This example on how to configure hitless vPC role change:
switch# show vpc rolevPC Role status ---------------------------------------------------- vPC role : secondary vPC system-mac : 00:23:04:ee:be:01 vPC system-priority : 32667 vPC local system-mac : 8c:60:4f:03:84:41 vPC local role-priority : 32668 vPC peer system-mac : 8c:60:4f:03:84:43 vPC peer role-priority : 32667 ! Configure vPC hitless role change on the device! switch(config)# vpc role preempt ! The following is an output from the show vpc role command after the vPC hitless feature is configured switch(config)# show vpc role vPC Role status ---------------------------------------------------- vPC role : primary vPC system-mac : 00:00:00:00:00:00 vPC system-priority : 32667 vPC local system-mac : 8c:60:4f:03:84:41 vPC local role-priority : 32666 vPC peer system-mac : 8c:60:4f:03:84:43 vPC peer role-priority : 32667 switch(config)#
The hitless vPC role change feature can be used in the following scenarios:
Role change request—When you want to change the roles of the peer devices in a vPC domain.
Primary switch reload—When the devices comes up after a reload and roles are defined, you can use the hitless vPC role change feature to restore the roles. For example, after a reload if the primary device takes the role of operational secondary and the secondary device takes the role of primary operational, you can change the vPC peer roles to their original defined roles using the vpc role preempt command.
![]() |
Always check the existing device role priority before switching vPC role. |
Dual-active recovery—In a dual-active recovery scenario, the vPC primary switch continues to be (operational) primary, but the vPC secondary switch becomes the targeted primary switch and keeps its vPC member ports up. You can use the vPC hitless feature and restore the device roles. After the Dual-active recovery, if one side is operational primary and the other side operational secondary, then you can use the vpc role preempt command to restore the device roles to be primary and secondary
11-21-2019 01:42 AM
Simply execute the following command
AGPRI# vpc role preempt
Please ensure peer-switch is enabled and operational('show spanning-tree summary'). Continue (yes/no)? [no] yes
AGPRI#
07-13-2020 08:03 AM - edited 07-13-2020 08:43 AM
Tried this in config mode on 5596s and get a "service not responding" message. I am disappointed they don't support the command.
07-04-2019 03:12 AM
11-06-2017 03:44 AM
Hi,
Cisco's recommendation is to match the vPC (operational) primary role with the root of STP & HSRP active.
If you want to change the operational role from one box to the other change the vpc domain role priority (lower wins the election). This is not preemptive.
!!During a maintenance window!! the steps should be (you want to make A primary operational; B is currently primary operational):
1. change role priority on the A box;
vpc domain 1
role priority lower_value_than_B_priority
2. Check the sticky bit on both boxes
"show sys internal vpcm info all | i i stick"
Example output:
N7K# show system internal vpcm info all | i i sticky
Sticky Master: FALSE
The B switch should have the value FALSE and A should be TRUE.
3. If B still has the TRUE value re-apply on it the current configured value - This means to reapply the original configuration for the role priority. If the role priority is default, then reapply the default. This operation will re-initiate the Sticky bit.
vpc domain 1
role priority same_priority_as_before
4. Check the output of "show sys internal vpcm info all | i i stick" again. Now the value should be FALSE on B and TRUE on A
5. shut vPC peer link (NOT the keep-alive link).
6. Check to see if role has changed with show vpc brief
7. Bring back up the vPC peer link.
Reference
- check Sticky bit Check paragraph 'option 1. phased approach' in this doc https://www.cisco.com/c/en/us/support/docs/interfaces-modules/nexus-7000-series-supervisor-1-module/119033-technote-nexus-00.html#anc7
- "You can also configure which of the vPC devices is the primary device. Changing the priority of the vPC peer devices can cause the interfaces in your network to go up and down. If you want to configure the role priority again to make one vPC device the primary device, configure the role priority on both the primary vPC device with a lower priority value and the secondary vPC device with the higher value. Then, shut down the port channel that is the vPC peer link on both devices by entering the shutdown command, and finally reenable the port channel on both devices by entering the no shutdown command." taken from here
https://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/nx-os/interfaces/configuration/guide/b-Cisco-Nexus-7000-Series-NX-OS-Interfaces-Configuration-Guide-Book/configuring-vpcs.html
11-12-2020 07:33 PM
this post seems to be too old and hope you have found a solution, if not, according my experience ( we had the same issue ) you have to follow what Jevgeni Rõžov mentioned,
1. either reload the secondary switch
2. or shut/no shut the peer links.
in our case, we were doing sofware updates, both switches had to reboot.
10-18-2021 10:41 AM
Stumbled across this thread in a google search. The OP was experiencing the issue of having the configured secondary switch (Nexus-9K-2, vPC role-priority 2) operating as primary despite clearly having a HIGHER priority number than Nexus-9K-1 (vPC role-riority 1). This usually happens during software upgrades when the secondary switch is rebooted first, takes over when the primary reboots, and stays that way once the primary comes back up. The reason for this is because (unlike with HSRP or VRRP) Nexus vPC roles DO NOT preempt automatically.
Thankfully there's an easy fix (as mentioned by Abhi_d_koenig ), you simply enter the command "vpc role preempt" in Privileged EXEC mode on the configured primary switch. It will query the configured vPC role-priorities on both switches and confirm that it can preempt. You should see a warning about spanning-tree summary and confirming that peer-switch is enabled and operational, if so you're good to go. This is also part of the graceful (hitless) vPC role change procedures.
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