After checking the system commits, we noticed that RE0 had its last commit in 2018, while RE1 had a recent commit on March 12, 2024. The customer mentioned they rebooted the device on March 12.
Further examination showed RE0 came up with alternate media (OAM), even though the customer confirmed they're not in the middle of maintenance work. They plan to arrange a maintenance window and onsite technical support.
Currently, RE0 is serving as the master, but we need to perform a mastership switchover. Then, we'll attempt JUNOS recovery for RE0 to bring it up from the JUNOS volume using the commands:
request system recover junos-volume
request system reboot junos
After the reboot, we'll ensure RE0 comes up with the JUNOS volume by checking the system alarms. If RE0 is up with the JUNOS volume, we'll verify the configuration on both RE0 and RE1. If synchronisation is needed, we'll perform it. In case of configuration loss, the customer will provide the backup configuration.