Form stack with production single switch

[MK2]

Good morning,

short and certainly simple question to which I have not found anything in the documentation:
I have a switch, this is in operation and configured. Now comes a second switch in the same cabinet and should be stacked with the first.

What is the procedure.
Switch off both and connect with the stacking cables, switch on again and form a stack from the potential stack in the dashboard? Do I need a downtime?

[cmr · Accepted solution]

@MK2 it is best to connect the cables with the switches off (pre-stage the new one first so it registers to the dashboard), but we have built quite a few stacks 'on the fly' and it usually works.  The process that we follow (when we can't find a downtime slot) is:

1. Configure stack in dashboard of old + new switch
2. Connect stacking cables from new to old switch
3. Power on new switch with a front port connection to the existing switch to give it access to the dashboard
4. Wait an hour for firmware upgrades/downgrades, registration and config to complete
5. If the stack port lights are both green and the front port connection now shows spanning tree blocking on the old switch end then the stacking has worked
6. Wait up to another hour for any stacking error messages to go away
7. Unplug front port connection and start using new switch in the stack.

This has worked multiple times with MS225/210 stacks and usually works with MS355 stacks, though occasionally a new switch needs a manual reboot to clear the stacking messages.  I have never had to reboot the existing switch so far...

[BrandonS]

I love step 4 and 6 being to wait for an hour 😉 My lack of patience often costs me time and causes headaches..

[cmr]

@BrandonS me too, hence I write the waiting into the procedure, as I'll always tend to not give enough time!!

[MK2]

Good morning,

first of all many thanks to all for the many feedbacks 😀

just tried this morning with a downtime, all switches off, new and old, switches connected with stack cable and switched on again.........no connection to the cloud. Stack cable pulled, the old switch was back online. the old switch has the uplink via an sfp. I was surprised. In the event log, I find strange SPT entries...... Previously, I had always created stacks only from scratch.

I try then times like online-provison variant one downtime the next days.

[MK2]

So, another early shift shows that I'am more confused than ever . Powered of all switches and pushed in the stack cables.
And see there, TADAAAA a potenial stack was detected.
Wondering why it not worked the day before....
After creating the stackit takes so many minutes till it came back online, while the stack was created the switches went to a reboot I suspect.

The old switch is connected to an upstream nexus 5672UP with an two port AGGR, since the stack is online one port is in blocking state to LOOP-GUARD.

While troubleshooting this things, a console would be nice, the status page show only the boring "trying to find a working ethernet connection" 😄

I'll check this next week to figure out what is causing the loop.