To enable ltcluster to support a replication cluster, the primary node must be registered with ltcluster. This installs the ltcluster extension and metadata objects, and adds a metadata record for the primary server:

    $ ltcluster -f /etc/ltcluster.conf primary register
    INFO: connecting to primary database...
    NOTICE: attempting to install extension "ltcluster"
    NOTICE: "ltcluster" extension successfully installed
    NOTICE: primary node record (id: 1) registered

Verify status of the cluster like this:

    $ ltcluster -f /etc/ltcluster.conf cluster show
     ID | Name  | Role    | Status    | Upstream | Connection string
    ----+-------+---------+-----------+----------+--------------------------------------------------------
     1  | node1 | primary | * running |          | host=node1 dbname=ltcluster user=ltcluster connect_timeout=2
  

The record in the ltcluster metadata table will look like this:

    ltcluster=# SELECT * FROM ltcluster.nodes;
    -[ RECORD 1 ]----+-------------------------------------------------------
    node_id          | 1
    upstream_node_id |
    active           | t
    node_name        | node1
    type             | primary
    location         | default
    priority         | 100
    conninfo         | host=node1 dbname=ltcluster user=ltcluster connect_timeout=2
    repluser         | ltcluster
    slot_name        |
    config_file      | /etc/ltcluster.conf

Each server in the replication cluster will have its own record. If ltclusterd is in use, the fields upstream_node_id, active and type will be updated when the node's status or role changes.