9300-48T stack conversion questions

[JaganV]

Hello guys,

i have a question on converting existing live switches into stack.

i have 3 units of 9300-48T working independently now.(same model, version 17.12.5 and same license)

Is there a way I can do this without ever reloading sw-1? Sw-2 and sw-3 can be reloaded or powered off.

Planning to do it this way.

1) provision the 3 switches in sw1 via provision command.

2) preconfigure members 2 and 3 port configuration on sw1 (will this work without the member joined?)

3) set priority sw-1 to 15

4) renumber sw2 and sw3, and reload. Once they come up, power down 2 and 3.

5) connect stack cables, and power on 2 and 3.

Will this work?

[M02@rt37]

Hello @JaganV 

You cannot form a new c9300 stackwise480 stack without reloading SW1 at least once....

You can provision members and pre-build configs on SW-1, yes, and you can renumber and power down SW-2/3 in advance, but the initial creation of a stack require all members to boot together while physicaly cabled in a ring so that master election and stack initialization can occur...

If sw1 stays up, it will remain a standalone switch and the others will not join it when powered on, likely resulting in join failures or "split-master" behavior.

So, the minimum disruption method is to preconfigure everything, power off all three switches, cable them, then power on SW1 first (it will become master) followed by SW2 and SW-3...

[balaji.bandi · Accepted solution]

At some point, you need to allow downtime because the port configuration changes during stack build.

I follow the steps below:

Switch1

switch 1 priority 15
switch 2 provision c9300-48t
switch 3 provision c9300-48t
Apply your port configs (e.g., interface gi2/0/1, gi3/0/1)

On SW-2 & SW-3 (Offline):
switch 1 renumber 2 (on SW-2) and switch 1 renumber 3 (on SW-3).
Reload these two so the new numbers take effect.
Once booted and verified as Switch 2 and Switch 3, power them off.
Physical Connection:
Connect the StackWise cables while SW-2 and SW-3 are powered OFF.
Power on SW-2 first, wait for it to join (verify with show switch on SW-1), then power on SW-3

Check my post for more steps :

https://community.cisco.com/t5/switching/basic-steps-to-creating-a-switch-stack-by-adding-second-switch/td-p/5014915

Since you have not mentioned the uplink, use Switch 1 and switch2 uplink modules to connect to the Core or Distribution switch.,

[Leo Laohoo]

Renumbering a switch, for example Switch 3 to become Switch 1, will require a reboot.

Adding new members to a stack will require the member switches to be powered off or else the entire stack will reboot.

[pieterh]

>>> You cannot form a new c9300 stackwise480 stack without reloading SW1 at least once.... <<<
I'm quite sure this is not how forming a stack is intended to behave

there is no need to reboot switch1, but of course accidents can happen, so maintainance window is preferred.
The operation of the switch stack continues uninterrupted during membership changes unless you remove the active switch or you add powered-on standalone switches or switch stacks.
NB! you allready have covered that  the new switches have same IOS version and license

- leave switch1 running
- erase the config of intended switch2 , but leave the switch number as "1"
- add it to the stack and power up
  it will join the stack and will be assigned number-2 and switch-1 will remain switch-1
  in the config the line "switch2 provision..." will automatically be added
  and the interfaces for switch2 will be added
- do same with intended switch3
- configure the new switchports
(- you can configure switch priority and premption to preserve that switch1 is the preferred stack master)
(- save the configuration)

alternatively you can preprovision switch2 and switch3 by adding the switch provision statements and creating the interfaces in advance.

• Offline Configuration to Provision a Stack Member

from there switch-1 handles this the same as replacing a defective stack member