ISSU/Dual SUPs for 9500 in ACI mode

[cowser1979]

Is there a way to take advantage of ISSU/dual sup failover in a 9500 in ACI mode?  I am thinking in terms of firmware management.  I have a fabric of multiple 9500 spines, and it would be helpful if i didn't not have to take a dataplane outage when upgrading FW.

thanks

[Tomas de Leon · Accepted solution]

In ACI, the 9500 Spine switches dual supervisors in "warm standby" mode.

Information from Release Notes:
The Cisco Nexus 9508 ACI-mode switch supports warm (stateless) standby where the state is not synched between the active and the standby supervisor modules. For an online insertion and removal (OIR) or reload of the active supervisor module, the standby supervisor module becomes active, but all modules in the switch are reset because the switchover is stateless. In the output of the show system redundancy status command, warm standby indicates stateless mode

In earlier releases of ACI code, admin users would need to upgrade the firmware, FPGAs, and BIOS individually.  There was no communication or firmware upgrades across the EOBC.  In later releases of ACI firmware versions, the standby supervisor is upgraded during a "Policy" upgrade task.  Manual upgrades on the Primary supervisor will not upgrade the warm standby supervisor.

After you perform an "Policy" upgrade, you can go to the CONSOLE of the warm standby supervisor and verify the supervisor has been upgraded also.

ie.

(none)# show system redundancy status
Redundancy mode
---------------
administrative: Warm
operational: Warm

(none)# cd /bootflash
(none)# ls
aci-n9000-dk9.12.0.2f.bin

(none)# cat /mnt/cfg/0/boot/grub/menu.lst.local
boot aci-n9000-dk9.12.0.2f.bin

(none)# cat /mnt/cfg/1/boot/grub/menu.lst.local
boot aci-n9000-dk9.12.0.2f.bin

Thank  you for using the Cisco Support Community for ACI!

T.

[Steev112]

Hi Tomas,

i just want to confirm what i understood, if i have two supervisors and the active one goes down, is the standby will not carry traffic as normal switches? if what i understood right, what is the benefit for dual supervisors in ACI

[cweinhold]

As an FYI,  as of the latest ACI 4.0 code, Nexus 9500 spines with dual supervisors still don't support any sort of stateful switchover (SSO or RPR). Today, a primary supervisor failure causes the switch to reboot to the secondary supervisor, taking it offline for several minutes.

This is no problem since ACI fabrics are built to tolerate outages of every spine or leaf (after all, code upgrades also cause these devices to reload).

What it really means is that there is zero reason to have dual supervisor engines in an ACI spine. Save yourself the money and stick to a single supervisor engine.