This article explains why the reth interfaces show DOWN even if one of node has all interfaces as UP.
When Node0 is primary and it's physical interfaces associated with reth is Down, the reth will report down. -------------------------------------------------------------------------------- {primary:node0} user@host# show chassis cluster status Cluster ID: 1 Node Priority Status Preempt Manual failover Redundancy group: 0 , Failover count: 1 node0 100 primary no no node1 1 secondary no no Redundancy group: 1 , Failover count: 1 node0 0 primary no no node1 0 secondary no no -------------------------------------------------------------------------------- {primary:node0} user@host> show interfaces terse | match reth ge-0/0/1.0 up down aenet --> reth1.0 ge-0/0/2.0 up down aenet --> reth0.0 ge-7/0/1.0 up up aenet --> reth1.0 ge-7/0/2.0 up up aenet --> reth0.0 reth0 up down reth0.0 up down inet 10.10.10.10/24 reth1 up down reth1.0 up down inet 10.0.0.0/24 reth2 up down -------------------------------------------------------------------------------- {primary:node1} user@host> show chassis cluster interfaces Redundant-ethernet Information: Name Status Redundancy-group reth0 Down 1 reth1 Down 1 reth2 Down Not configured --------------------------------------------------------------------------------
This is expected behaviour as the cluster is active on the Node that is having its physical interfaces associated with reth DOWN.
To make the reth interfaces UP from the backup node, failover the cluster to the backup node manually.
Or configure interface monitoring to do this automatically.
Reference - https://www.juniper.net/documentation/us/en/software/junos/chassis-cluster-security-devices/topics/topic-map/security-chassis-cluster-interface-monitoring.html