Addt to the Salt state CARP the file /usr/local/etc/devd/carp.conf on router nodes.
This configuration allows devd to listen for CARP state changes (MASTER/BACKUP)
and automatically trigger the OVH failover script.

Ref T2276

• Applied state on router-002:
  
  salt 'router-002' state.apply roles/router test=True
  
  salt 'router-002' state.apply roles/router

• Applied state on router-003:
  
  salt 'router-003' state.apply roles/router test=True
  
  salt 'router-003' state.apply roles/router