Configuration

Each node has identity parameters that are configured through the parameters in <cluster>.hosts and <cluster>.vars.

Pigsty uses IP as a unique identifier for database nodes. This IP must be the IP that the database instance listens to and serves externally, But it would be inappropriate to use a public IP address!

This is very important. The IP is the inventory_hostname of the host in the inventory, which is reflected as the key in the <cluster>.hosts object.

You can use ansible_* parameters to overwrite ssh behavior, e.g. connect via domain name / alias, but the primary IPv4 is still the core identity of the node.

nodename and node_cluster are not mandatory; nodename will use the node’s current hostname by default, while node_cluster will use the fixed default value: nodes.

If node_id_from_pg is enabled, the node will borrow PGSQL identity and use it as Node’s identity, i.e. node_cluster is set to pg_cluster if applicable, and nodename is set to ${pg_cluster}-${pg_seq}. If nodename_overwrite is enabled, node’s hostname will be overwritten by nodename

Pigsty labels a node with identity parameters in the monitoring system. Which maps nodename to ins, and node_cluster into cls.

The following cluster config declares a three-node node cluster:

node-test:
  hosts:
    10.10.10.11: { nodename: node-test-1 }
    10.10.10.12: { nodename: node-test-2 }
    10.10.10.13: { nodename: node-test-3 }
  vars:
    node_cluster: node-test

Default values:

#nodename:           # [INSTANCE] # node instance identity, use hostname if missing, optional
node_cluster: nodes   # [CLUSTER] # node cluster identity, use 'nodes' if missing, optional
nodename_overwrite: true          # overwrite node's hostname with nodename?
nodename_exchange: false          # exchange nodename among play hosts?
node_id_from_pg: true             # use postgres identity as node identity if applicable?