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Configuring Mastership of an EX Series Virtual Chassis (CLI Procedure)

Note: This topic applies to all EX Series Virtual Chassis except EX8200 Virtual Chassis. See Configuring an EX8200 Virtual Chassis (CLI Procedure) for information about EX8200 Virtual Chassis.

You can designate the role (master, backup, or linecard) that a member switch performs within any Virtual Chassis, whether or not you are using a preprovisioned configuration.

Note: A Virtual Chassis configuration has two Routing Engines—one is the switch in the master role and the other is the switch in the backup role. Therefore, we recommend that you always use commit synchronize rather than commit to save configuration changes made for a Virtual Chassis. This ensures that the configuration changes are saved in both Routing Engines.

This topic describes:

• Configuring Mastership Using a Preprovisioned Configuration File
• Configuring Mastership Using a Configuration File That Is Not Preprovisioned

Configuring Mastership Using a Preprovisioned Configuration File

1. Note the serial numbers of the switches that you want to function in the master role and backup role.
2. Power on only the switch that you want to function in the master role.
3. Edit the configuration to specify the preprovisioned configuration mode:
   [edit virtual-chassis]
user@switch# set preprovisioned

4. Specify the serial numbers of the member switches that you want to function as master and backup, specifying their role as routing-engine:
   [edit]

   
   

   user@switch# set virtual-chassis member 0 serial-number abc123 role routing-engine

   
   

   user@switch# set virtual-chassis member 1 serial-number def456 role routing-engine

   
   

   Note: You cannot directly modify the mastership priority value when you are using a preprovisioned configuration. The mastership priority values are generated automatically and controlled by the role that is assigned to the member switch in the configuration file. The two members assigned the routing-engine role are assigned the same mastership priority value (128). However, the member that was powered on first has higher priority for the master role election according to the master election algorithm. See Understanding How the Master in an EX Series Virtual Chassis Is Elected. Only two members can be configured with the routing-engine role.

5. Specify the serial numbers of any other member switches that you are including in the Virtual Chassis configuration. You can also explicitly configure their role as line-card.

Configuring Mastership Using a Configuration File That Is Not Preprovisioned

1. Power on only the switch that you want to function in the master role.
2. Configure the highest possible mastership priority value (255) for the member that you want to function in the master role:
   [edit virtual-chassis]
user@switch# set member 0 mastership-priority 255
3. Configure the same mastership priority value (continue to edit the Virtual Chassis configuration on the master) for the member that you want to be in the backup role:
   [edit virtual-chassis]
user@switch# set member 1 mastership-priority 255

   Note: We recommend that the master and backup have the same mastership priority value to prevent the master and backup status from switching back and forth between master and backup members in failover conditions.

4. Use the default mastership priority value (128) for the remaining member switches or configure the mastership priority to a value that is lower than the value specified for members functioning in the master and backup roles.