Replacing All C9300 Stack Members

[MasonK]

I've got a stack of 4x Catalyst 9300-48P switches that I'm replacing with C9300X-48HX's, and am curious about the best approach to take. The C9300 and C9300X are supposed to be compatible with one another in a stack, so I'm wondering if it would be viable to replace the switches one at a time - I imagine I would just need to change the master switch temporarily (IE: Switch 1 is master; make switch 2 the master, replace switch 1, then make new switch 1 the master). Does that seem like a valid approach, or would I be better off just copying the config from the original stack onto the new stack of 9300X's and replacing them all at once? 

[M02@rt37 · Accepted solution]

Hello @MasonK 

If you replace one switch at a time, you will need to pin the stack master, remove a member, power it down, insert the 9300x, let it join, and verify compatibility and repeat for each switch while carefully watching stack power/stackwise links (and software versions).

This is doable, but any misstep can cause a full stack reload or split....

[MasonK]

Okay, understood. I'll just go ahead with replacing the full stack to prevent any complications.

[balaji.bandi · Accepted solution]

Look at the stack guidelines - Cat 9300 and Cat 9300X is compatible :

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/hardware/install/b_c9300_hig/Installing-a-switch.html

If you have downtime, Build offline all new switches and use same configuation and apply on the stack.

in the mainenance window, rack on top of each switch depends on space. turn off whole statck (OLD) bring new one, and connect uplink and check all uplink ok, move patch cables from old to new (make sure all ports are admin up).

Ensure all switches (old and new) run compatible Cisco IOS XE software versions (e.g., 17.6.x or newer is recommended for 

C9300X support) and the same license level. Back up the current configuration.

If no maintenance then use below steps :

show switch to confirm which switch is the active master.

Replace a Member (Not the Active):
Power off the C9300 member switch you are replacing.
Physically remove the old switch from the rack.
Install the new C9300X in its place.
Connect the stack cables and network cables.
Ensure the new switch is powered off before connecting the data stack cables to the live stack to prevent a stack merge condition.
Power on the new C9300X switch.

Do verification and Repeat the process for the remaining member switches, ensuring you still avoid removing the active switch until it's the last one.

[Joseph W. Doherty]

It may be a valid approach, but I suspect it will take much longer, overall, to swap out all 4 switches.

Another possible advantage of your proposed approach, in theory, it would be a rolling outage, i.e. usually only one switch off-line at any point in time.

If you setup the replacement set of switches, external to the existing network, and configure it, in theory, the actually physically swap should go rather rapidly.  I.e. power down existing stack, pull it out, put in replacement stack, power up.

Another possible advantage I see to your approach, you might swap out one switch at a time during 4 different maintenance periods.  Swapping out, just one switch, during a maintenance period will probably take less time than swapping all 4 switches.

[MasonK]

Thanks. Downtime isn't an issue thankfully, we've got about a 3hr window to work with. I'm thinking I'll just go ahead with the full stack swap instead of a one-at-a-time approach, but good to know others see reason behind that in case I do need to go that route with another stack in the future.