Stacking more than two 3750x-48p

[kawhite_MB]

I am fairly new to stacking switches but I think I have a good handle on it so far. We have a bunch of 3750x-48P that we are using to replace some old 2950's. I have no issues stacking the first two switches but when I connect the third it seems to be a huge headache to get it to stack. 

All the switches are running the latest OS 15.2(4)E10. 

My process is as follows:

After first two are stacked successfully, I power on switch 3 (not stacked) and make sure the OS is correct.

I provision a third switch in the stack: switch 3 provision WS-C3750X-48P

Power off switch 3

Connect stack cables to switch 3

power on switch 3

At this point switch 3 boots but does not join the stack.

I have tried setting the priorities (Switch 1 - 15, Switch 2 - 14, Switch 3 - 12) but it still doesn't work.

Stack cables are configured in full ring:

Switch 1 stack port 1 connects to switch 2 stack port 2

Switch 2 stack port 1 connects to switch 3 stack port 2

Switch 1 stack port 2 connects to switch 3 stack port 1

Checking the stack it still shows switch 3 as provisioned.

Switch 3 still only shows itself when running "show switch"

Any help is appreciated.

[balaji.bandi]

Can you post exiting stack running show switch output

Technical you did the steps as expected, if you mentioned the switch running standalone still, that means it not have any contact with exiting stack, so first place i switch of the new device, check the Physical cables, make sure you plugged in right ports cross check.

always check the Logs on Live stack any issue, show switch give you on going stack join device if detected.

here is guide for reference :

https://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/71925-cat3750-create-switch-stks.html

still issue post the config of

show run from Live stack

and new device show run

[kawhite_MB]

All the cables have been checked many times. 

Here is the "show switch" outputs from the stack and from switch 3:

Switch/Stack Mac Address : b838.6137.ac00
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master b838.6137.ac00 15 3 Ready
2 Member 6c99.89b2.7d00 14 3 Ready
3 Member 0000.0000.0000 0 0 Provisioned

Switch/Stack Mac Address : c067.af82.d380
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master c067.af82.d380 12 3 Ready

There is no config on switch 3. It has been reset to factory default after the OS upgrade. When it completed booting it comes up with the Initial Config prompt.

The stack will eventually work, but only after a number of random reloads of switch 2 and 3.

From what I understand, I should not have to reload switch 2 in order to add a switch 3. It should be plug it into the stack and power it on.

[balaji.bandi]

yes, there is no requirement for a stack member to reload to add a new stack member.

so is this resolve now, or still have an issue?

[kawhite_MB]

This particular stack is working now but I have had this issue with every stack of more that two switches that I have setup (3 or 4). I just don't know why it isn't working like it should. I've had to reboot other switches in the stack before the new stack member will join. If we have a stack switch go bad, I want to know that I can replace it without having to reboot the other switches in the stack and so far, this has not been the case.

[balaji.bandi]

My self done many on stacking on 3750X  and new cat 9K, i have never seen this issue you mentioned, i still stick with my comment done before there is no requirement to reboot for the stack to add new member.

since you having issue, i would like to review your config how it was setup

the one you have not yet done and going to be done, Like to see below output.

show run

show version

[Joseph W. Doherty]

I recall (?) when you pre-provision switches, you need to both do so on the stack and the stack member to be added.

If you don't pre-provision, I further recall (?) the switch member to be added still should be "configured" to be a switch ready to be added to the stack for the first time.

[kawhite_MB]

Joseph,

So, I provision the third switch in the stack using

#switch 3 provision WS-3750x-48P.

Would I need to provision both switches that are already in the stack on the third?

switch1(config)#switch 1 provision WS-3750x-48P

switch1(config)#switch 2 provision WS-3750x-48P

In order to do that, I would need to renumber the switch to 3 due to it being switch 1 in it's own stack

switch1(config)#switch 1 renumber 3

That would require a reload. 

After the reload, I could set the priority on switch 3 to lower than the other two and provision switches 1 and 2.

switch3(config)#switch 3 priority 12

switch3(config)#switch 1 provision WS-3750x-48P

switch3(config)#switch 2 provision WS-3750x-48P

Then reload switch 3 again.

Seems like a lot of extra steps. I don't believe I have read anywhere about having to provision the other switches in the stack on the new member.

If someone else can verify this, I will give it a try on the next stack.

[balaji.bandi]

The docment i have shared very clear steps. if you get 5min that document cover the steps.

[Joseph W. Doherty]

One of the features of provisioning switches, is you can configure (I recall) ports for the stack member (on the existing stack) before the stack member joins the stack.  In other words, when the "new" stack member joins a stack it's like if it were already a member of the stack that lost power and then regained it.

[cmcclinton]

If you are just building the stacks you can skip the provisioning config when the new switch (3rd) is added to the stack of 2 it will become switch 3. The provisioning command allows you to add config to stack for new switch before it is installed by creating the logical entity in the config.

If the switches have been used previously in stacks as well as erasing the config you might also want to check the switch number as it may still think that it was perhaps switch 3, 4, 5 etc in a previous life. So erase the config and check the switch number and priority value before introducing it to the new stack. 

[kawhite_MB]

Just ran into this same issue again. Switch 3 has never been plugged in and still wont stack.

Output from stack:

swmdc120#sho switch
Switch/Stack Mac Address : 10f3.11d4.cb00
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 10f3.11d4.cb00 15 3 Ready
2 Member 3c08.f6f1.e400 14 3 Ready
3 Member 0000.0000.0000 0 0 Provisioned

Switch 3 is cabled the same as mentioned before but still not joining the stack.

[balaji.bandi]

 Switch 3 has never been plugged in and still wont stack.

Switch 3 is cabled the same as mentioned before but still not joining the stack.

your 2 statements still confusing here.

post-show run from the current running stack - also show version

connect the console to switch 3, post-show run, and show version also.

here is example to connect stack-cable when you introducing new switch and issue provision command on the running stack

https://networkguy.de/stackwise-configuration-with-cisco-catalyst-3750-x-series/