3650 Stacked Firmware Upgrade

Brad.Bird · ‎05-08-2018

Hey everyone, I plan on upgrading our core switches from some very old firmware to cat3k_caa-universalk9.16.03.06.SPA.bin

2 switches are stacked, SSO failover set up, both in install mode.

I am wondering if it is possible to do this with some amount of fault tolerance as we don't have a spare switch incase it gets messed up. Ideally I can upgrade one of the switches in the stack, test that everything works fine on that switch and the upgrade the second and have the switch numbers not change.

These are our corse switches and we don't have (another) spare so if I mess something up by upgrading them both at the same time I am kind of screwed.

Thanks in advance for the knowledge.

Leo Laohoo · ‎05-08-2018

Not possible.
If the switch are in a stack then both must be rebooted simultaneously.

Brad.Bird · ‎05-09-2018

Would it be advisable at all to unstack the switches, upgrade the firmware on one, test, then upgrade the other and restack? Is this overkill? What are the chances a firmware update will have adverse effects on our network?

Reza Sharifi · ‎05-09-2018

No, I don't recommend unstacking the switches. If you have a maintenance window, there is no need to complicate things by breaking the stack and upgrading them. Also, in the end, it will probably take you longer and cause downtime anyway. Rebooting the whole stack is so much easier. Also, since you are going from an old version to 16.03.06, I recommend you have someone at that location in case the switches hang or go to Rommon mode after the reboot and need to be unplugged from the power.

HTH

Leo Laohoo · ‎05-09-2018

@Brad.Bird wrote:
Would it be advisable at all to unstack the switches, upgrade the firmware on one, test, then upgrade the other and restack? Is this overkill? What are the chances a firmware update will have adverse effects on our network?

No, this is not recommended. It will only cause more issues and one of them is called "split brain".

As what Reza said, it will only make the boot-up of the entire stack more complicated.