How to Replace Failed Switch in a Cisco Switch Stack | NO OUTAGE OR STACK REBOOT

Replacing a failed switch in a cisco switch stack is one of the frequently done task in the network world. This must be done properly without rebooting entire switch stack that can cause major network outage in a production environment, especially with a large switch stack. This video explains how this can be done.

[@afterbirthbob]

Thanks for the demo. I need to do one next week so good to see. I will need to reboot to make the replacement master again though.

[@networktutor640]

Any time!

[@tammineedimahesh3738]

Thanks for the demo and good explanation

[@networktutor640]

Glad it was helpful!

[@CRK1918]

Thank you for your video😁, because this kind of cool you can set ether-channel between them, if the device using the etherchannel LACP technically the device will never down during that one switch outage.

[@networktutor640]

Yes, you are right

[@shivanarayana4976]

very nice and clear explanation sir

[@networktutor640]

Thanks and welcome

[@akhileshtiwari2425]

GOOD DEMONSTRATION!!

[@networktutor640]

thank you !!

[@vinodvv613]

It was very helpful. Could you please upload a video how to do a stack configuration with two new switches. My requirement was I have two switches in stack both are faulty and i need to configure two switches in stack.

[@networktutor640]

if you have both switches bad, you need to install the first switch and copy the backed up config ot its startup config. so you have the stack running with one switch. Then add the second switch (just a blank switch with no config - make sure you set the switch number and priority correctly). Second switch will get the config automatically from the master/active. Hope this helps.

[@vinodvv613]

Thanks for your explanation
Please share how can we set new switch master, we set priority 15 but still Secondary acting as master.

[@networktutor640]

Did you reboot the stack? how many switches in your stack?

[@vinodvv613]

​@@networktutor640 In this video the Low priority switch acting as a Master...First switch priority was 15 and how we can set the first switch back to master. Beginning of this video first switch (Faulty one) was master.

[@neosmith7272]

use "CTRL + SHIFT + 6 + X" to break that ping; Also I don't think its recommended way to configure the new switch priority prior as master; you can do it post configuration pull up after switch is stacked

[@networktutor640]

Thanks for the keyboard short cut. I will try. With regards to setting priority, it doesn't matter when you set the priority. Because, when you boo the replacement switch it won't become as master until next reboot. Best practice is do it before.

[@ashwinadith8072]

But the priority hight value switch should become master right ?

[@networktutor640]

Yes. Only when there is reboot.

[@shawnphillips1220]

What I thought you said no outages? You reload the switch and it rebooted so wouldn't that be an outage if it were live?

[@networktutor640]

think about if this stack has 9 switches and only one went bad. Obviously there is an outage for those who were connected to that switch, but after replacing the failed switch in the stack, you are not rebooting the entire stack to cause a massive outage. that is what i meant without an outage. sorry that my languge is not that clear enough.

[@shawnphillips1220]

@@networktutor640 no worries thank you for explaining.

[@vinaygupta2436]

You have given priority 15 to the new switch means your existing configuration would be collapsed....this is going to be a massive failure in live network... You have to give least priority to the switch which you are adding so that it will take the configuration from existing MASTER. Once done change the priority to 15.

[@networktutor640]

I am replacing switch 1. So the priority should be 15?

[@networktutor640]

The way you discribed will also work but it will add more steps and longer time to get the stack back to its normal config. Let me explain you how you can make it short: First understand that your Master already failed and and the switch with priority 14 took over the master. Also it is the best practice that your master sits on top of your physical rack
1. you configure the new switch to Priority 15 and this switch will be added as a member and will get the config from the current master
2. Now reboot the stack - switch 1 will become as master now
Now your stack is back to normal - does this make sense Sir

[@aussietramp]

Question: in the startup of the stack...usually there is the config
sh run | i provision
switch 1 provision xxxx.xxxx.xxx.xxxx
switch 2 provision yyy-yyyy-yyyy-yyyy".
When you replace the switch 2 dont you need to remove the "switch 2 provision yyy-yyyy-yyyy-yyyy" line and replace it with the new command "switch 2 provision zzzz.zzzz.zzzz.zzzz"?
conf t
no switch 2 provision yyy-yyyy-yyyy-yyyy
switch 2 provision zzzz.zzzz.zzzz.zzzz

[@networktutor640]

Yes. You need to delete the old provision.