This article assists you with converting a Virtual Chassis member role to the primary Routing Engine role when you are using non-provisioned configuration. This will help users who prefer to change any member in a Virtual Chassis to a Routing Engine role. The article applies to Legacy and EX Series Switches with ELS devices. 

The 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] .

• How do I change a Virtual Chassis member to the Routing Engine?

• I want to change my Linecard member to the Routing Engine role.

• I want to change my Backup member to the Primary Routing Engine role.

• A different member is preferred to be in the Primary Routing Engine role.

For example, in the show virtual-chassis output below, FPC 0 - (BR0200000776) is acting as the primary RE.

root@EX4200-VC> 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    127       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)

Increase the mastership-priority  parameter of the device that you desire to change to a  higher value than that of the current primary Routing Engine. (On all members, the mastership-priority value is 128 by default.

Important: During a Routing Engine switchover, network downtime can occur. Juniper recommends making these changes during a Maintenance Window. For more information about how the switchover affects the Virtual Chassis, refer to Understanding Graceful Routing Engine Switchover .

In the example above, the mastership-priority  parameter of Member FPC 0 is modified to be higher than the current primary Routing Engine (FPC 1) with the following command:

root@EX4200-VC# set virtual-chassis member 0 mastership-priority 129

After changing the parameter, a commit synchronize needs to be executed (unless it is already configured):

root@EX4200-VC# commit synchronize

Refer to KB12879 [juniper.net] for additional information about commit synchronize .

The 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       BR0208233776 	ex4200-24f   129        Master*      1  vcp-0      
1 (FPC 1)   Prsnt       BR0209456997 	ex4200-24f   128        Backup       2  vcp-0      
                                                                             0  vcp-1      
2 (FPC 2)   Prsnt       BR0208233803 	ex4200-24f   128        Linecard     1  vcp-1      

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

To understand the Routing Engine election process in a Virtual Chassis before making a new member as primary, refer to Understanding How the Primary in a Virtual Chassis Is Elected .

In some combinations of EX devices that form a Virtual Chassis, only certain platforms can work as Routing Engines. Review it here:  Understanding EX Series Virtual Chassis .

2022-03-10: Updated article with default mastership-priority information

2021-11-30: Article updated with new links on what devices can be REs, and links to switchover downtime

2021-03-25: Updated article terminology to align with Juniper's Inclusion & Diversity initiatives

2020-04-15: Article reviewed for accuracy. Minor changes made to reflect the stile of configuration being used for this example (non-provisioned), as well as minor corrections on the output under solution.