After a maintenance window to add JSU packages to both Routing Engines on router labrouter, the customer noticed that the router no longer has IRB interfaces, even though the relevant configurations are present. 

The following steps were performed by the customer:

• Disabled GRES, NSR, and other features on the master Routing Engine (RE0)
• Restarted chassis-control on the backup RE (RE1) after the installtion of JSU Package 
• Mastership switched to RE1 (without GRES)
• Restarted chassis-control on RE0 after the installtion of JSU Package 
• Enabled GRES, NSR, and other features on RE1 (now master)
• Mastership switched to RE0
• Mastership switched to RE1
• Mastership switched to RE0
• Mastership switched to RE1
• Disabled GRES/NSR on RE1 (master)
• Mastership switched to RE0 (without GRES/NSR)
• GRES/NSR activated on master Routing Engine (RE0).

Hostname: re0.labrouter

Model: mx960

Junos: 21.2X8.1

JUNOS Selective Update J1.1 (for: /usr/share/pfe/mpc-2e-3e-ng.jbf /usr/share/pfe/npc.jbf /usr/share/pfe/rmpc.jbf /usr/share/pfe/smpc.elf /usr/share/pfe/smpc_re.elf) [21.2X8-J1.1]

{master}

[email protected]> show interfaces terse irb

Oct 02 12:36:15

error: device irb not found

The recommended restoration step is to perform a graceful mastership switchover.

• Deactivate GRES/NSR
• Reboot the backup Routing Engine (RE)
• Reactivate GRES/NSR
• Perform a graceful mastership switchover