Description

On a router that supports multiple Routing Engines, if you want different configurations to be applied to Routing Engine 0 and Routing Engine 1 using group configuration, then use special group names re0 (for routing engine 0) and re1 (for routing engine 1).

This article provides more details and also gives the configuration to change the group names accordingly.

Symptoms

If the group names for routing-engine 0 and routing-engine 1 are not configured as re0 and re1, then the configuration may not be applied to the backup RE.

The following is an example when configuring different hostnames under the two REs: 

groups {
    test-re0 { 
        system {
            host-name RE0; 
        }
    }
    test-re1 {  
        system {
            host-name RE1; 
        }
    }
}
apply-groups [ test-re0 test-re1 ];

If the above is configured on a dual-RE router and no hostname is configured (apart from the groups), which overrides the configuration, then the test-re1 configuration will not be applied to the backup RE. Both the REs show the hostname as "RE0." 

{MASTER}  
labroot@RE0> 

{MASTER}
labroot@RE0> request routing-engine login other-routing-engine 
Last login: Mon Mar 15 11:36:44 from re0

--- JUNOS 16.1X8.1 Kernel 64-bit  JNPR-10.3-20180310.ba55661_buil

{BACKUP} 
labroot@RE0>

Solution

On routers that support multiple Routing Engines, use the following two special group names:

  • re0: Configuration statements that are to be applied to the Routing Engine in slot 0

  • re1: Configuration statements that are to be applied to the Routing Engine in slot 1

Using different group names for the same purpose will not work. The same rule applies to all dual RE environments, including guest network functions (GNF) in Junos Node Slicing.

To change the group names to re0 and re1, use the following configuration: 

groups {
    re0 {    
        system {
            host-name RE0;
        }
    }
    re1 {
        system {
            host-name RE1;
        }
    }
}
apply-groups [ re0 re1 ];

Now, the backup RE has the correct hostname: 

{MASTER}
labroot@RE0> 

{MASTER}
labroot@RE0> request routing-engine login other-routing-engine 
Last login: Mon Mar 15 12:09:34 from re0

--- JUNOS 16.1X8.1 Kernel 64-bit  JNPR-10.3-20180310.ba55661_buil

{BACKUP}
labroot@RE1>

Modification History

2021-05-12: Minor spelling correction made, related links to technical documentation added

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