Cat 9300 Master switch replace from Stack

[SKVN]

Hi Expert,

I've some issue with stack switch. I've currently 9300 3 stack switch. The Master switch has some PSU issue and we are planning to replace the switch with brand new one. I would like to know what is the best practice to replace the Master switch with new one 

H/W Current
Switch# Role Mac Address Priority Version State
-------------------------------------------------------------------------------------
*1 Active 2c01.b585.3b80 1 V02 Ready
2 Standby 2c01.b59e.1380 1 V02 Ready
3 Member 2c01.b5a4.c300 1 V02 Ready

[M02@rt37]

Hello @SKVN 

Please follow that: https://video.cisco.com/detail/video/6316271140112

[Flavio Miranda]

@SKVN 

 Prepare the switch before connecting to the stack. Put it on the same version as the others, configure it with high priority in order for the switch take over as master and upload the last config to it.

 After that, just replace the switch and wait for the stack to be formed. Do it in maintenance windows.

[SKVN]

@Flavio Miranda Thanks for your response. But i've another question on this 

As per your answer i do understand we need to connect new switch as 4th stack on this existing setup, But we do not have the dala stack cable to connect 

What my plan is for remove the master then connect existing one, But i believe before that i may need to make the current standby switch as Master, But i'm confused . Is that the right way ?

[M02@rt37]

@SKVN 

In détail:

If you do not have a spare stack cable to temporarily add the replacement switch as a fourth member, your approach of removing the faulty master and promoting the current standby to master is correct. 

First, ensure the current standby switch (Switch 2) is prepared to take over as the master. In a Cisco Catalyst stack, the standby automatically assumes the master role if the active switch fails or is removed. However, to ensure a smooth transition, you should manually increase the priority of Switch 2 to ensure it is the designated master during this process. This step avoids any ambiguity in stack role election during the transition.

Next, you can safely power down and remove the faulty master switch (Switch 1) from the stack. Disconnect its stack cables and any other physical connections. Once this is done, verify that the standby switch (Switch 2) has become the new master. You can confirm this using the appropriate show commands to check the stack roles and statuses.

After removing the faulty switch, you can introduce the new switch to the stack in its place. Before connecting it, ensure the replacement switch has the same software version as the stack. If the software version differs, upgrade or downgrade it to match the stack. This step prevents version mismatch issues and ensures smooth integration into the stack. Once aligned, connect the replacement switch to the stack using the existing stack cables and power it on. The replacement switch will inherit the configuration from the master (Switch 2) and join the stack as a member.

Finally, if you want the replacement switch to eventually serve as the master, you can set its stack priority higher than the other switches. This ensures that in the event of a stack reload, the replacement switch will assume the master role.

[Flavio Miranda]

No,you got me wrong.  Prepare the new switch but do not connect it to the stack just yet. Use console cable, ethernet cable and PC to upgrade, transfer the config file and make it master by assigning higher priority

switch stack-member-number priority new-priority-value

 After this process you disconnect the faulty switch and connect the new one.

[SKVN]

M02@rt37 Appreciate the details explanation. 

I believe once we change the priority for the second switch it need reboot the entire stack to take it as Master right?

Correct me if i'm wrong

[M02@rt37 · Accepted solution]

@SKVN 

Correct! Simply changing the priority of the second switch (Switch 2) does not immediately make it the master. The priority determines which switch is preferred to become the master during the next election, but a master election only occurs under specific circumstances such as a stack reload, the failure or removal of the current master, or when a new switch with a higher priority joins the stack and the stack is reloaded. If you want Switch 2 to immediately take over as the master after changing its priority, you would need to reload the entire stack, which reboots all switches and causes downtime. However, in your case, since the current master (Switch 1) has a PSU issue and needs to be replaced, the better approach is to manually remove or power down the faulty master. This will automatically trigger a master election, during which Switch 2, with its higher priority, will take over as the new master without requiring a full stack reload. Once the election is complete, the stack will continue to operate with minimal disruption. After removing the faulty switch, you can connect the replacement switch to the stack, ensuring it has the same IOS version as the other members, and it will inherit the configuration from the new master. By removing the current master instead of reloading the entire stack, you avoid unnecessary downtime while ensuring that the new priority settings take effect and that Switch 2 becomes the active master. This method is more efficient and ensures the network remains operational during the transition.

[SKVN]

Thanks @Flavio Miranda 

[Leo Laohoo]

Before starting, please check if this command is present in the config of the stack: 

software auto-upgrade enable 

Let me explain what this command do:  The switch master will push the firmware to any new switch member of the stack.  

1. To replace the switch master, make sure the new switch has no config.  I prefer using the command "factory-reset config" to clean up switch config.  
2. Next, power down the switch master, remove the stacking cables (including power-stack cables) and remove the master. 
3. DO NOT POWER UP the new switch member. 
4. Install the new switch master. 
5. Attach the data stacking-cable ONLY.  
6. Insert the power supply and energize.  
7. Attach the power-stacking cable.  
8. Configure switch priority