Description

This article assists you with converting a Virtual Chassis’s Role from Linecard to Back-Up. This document will help the user who prefers to make a Linecard of a Virtual Chassis to a Backup role.

This article is part of the EX Resolution Guide: KB21064 - Verifying health of Virtual Chassis and troubleshoot if the members are not all present [juniper.net] .

Symptoms

  • How do I change my Linecard to a Backup?
  • I want to make my Linecard as a Back-up Role.
  • A different member is preferred to be backup.

For example, in the 'show virtual-chassis' output below, FPC 0 - (BR0200000776) is preferred to act as Backup. 

root@EX4200-VC# run show virtual-chassis    

Virtual Chassis ID: 6eb0.0094.e64b
                                          Mastership            Neighbor List  
Member ID   Status   Serial No    	Model          priority   Role     ID  Interface
0 (FPC 0)   Prsnt    BR0200000776 	ex4200-24f     128        Linecard  1  vcp-0      
1 (FPC 1)   Prsnt    BR0200000997 	ex4200-24f     128        Master*   2  vcp-0      
                                                                            0  vcp-1      
2 (FPC 2)   Prsnt    BR0200000803 	ex4200-24f     128        Backup    1  vcp-1      

Member ID for next new member: 3 (FPC 3)

Solution

Reduce the mastership-priority parameter of the existing Backup to be lower that the expected Backup.

In the example above, reduce the mastership-priority of Member FPC 2 to be lower than the 'expected' Backup Member FPC 0 with the following command:
root@EX4100-VC# set virtual-chassis member 2 mastership-priority 127
After changing the mastership-priority, a commit synchronize needs to be executed. 
root@EX4100-VC# commit synchronize
Refer to KB12879 [juniper.net] on understanding commit synchronize .
 

The end result will be as follows: 

root@EX4200-VC# run show virtual-chassis    

Virtual Chassis ID: 6eb0.0094.e64b
                    Mastership            Neighbor List 
Member ID   Status      Serial No     Model        priority   Role        ID  Interface
0 (FPC 0)   Prsnt       BR0200000776  ex4200-24f   128        Backup       1  vcp-0     
1 (FPC 1)   Prsnt       BR0200000997  ex4200-24f   128        Master*      2  vcp-0     
                                                                             0  vcp-1     
2 (FPC 2)   Prsnt       BR0200000803  ex4200-24f   127        Linecard     1  vcp-1      

Member ID for next new member: 3 (FPC 3)

 

Related links in the Technical Documentation: 

Modification History

2021-04-06: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives
2020-08-13: Article reviewed for accuracy; no changes required.

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