pg_autoctl create formation¶
pg_autoctl create formation - Create a new formation on the pg_auto_failover monitor
This command registers a new formation on the monitor, with the specified kind:
usage: pg_autoctl create formation [ --pgdata --monitor --formation --kind --dbname --with-secondary --without-secondary ] --pgdata path to data directory --monitor pg_auto_failover Monitor Postgres URL --formation name of the formation to create --kind formation kind, either "pgsql" or "citus" --dbname name for postgres database to use in this formation --enable-secondary create a formation that has multiple nodes that can be used for fail over when others have issues --disable-secondary create a citus formation without nodes to fail over to --number-sync-standbys minimum number of standbys to confirm write
A single pg_auto_failover monitor may manage any number of formations, each composed of at least one Postgres service group. This commands creates a new formation so that it is then possible to register Postgres nodes in the new formation.
The following options are available to
pg_autoctl create formation:
Location where to initialize a Postgres database cluster, using either
pg_basebackup. Defaults to the environment variable
Postgres URI used to connect to the monitor. Must use the
autoctl_nodeusername and target the
pg_auto_failoverdatabase name. It is possible to show the Postgres URI from the monitor node using the command pg_autoctl show uri.
Name of the formation to create.
A pg_auto_failover formation could be of kind
pgsqlor of kind
citus. At the moment
citusformation kinds are not managed in the Open Source version of pg_auto_failover.
Name of the database to use in the formation, mostly useful to formation kinds
cituswhere the Citus extension is only installed in a single target database.
The formation to be created allows using standby nodes. Defaults to
true. Mostly useful for Citus formations.
Postgres streaming replication uses
synchronous_standby_namesto setup how many standby nodes should have received a copy of the transaction data. When using pg_auto_failover this setup is handled at the formation level.
Defaults to zero when creating the first two Postgres nodes in a formation in the same group. When set to zero pg_auto_failover uses synchronous replication only when a standby node is available: the idea is to allow failover, this setting does not allow proper HA for Postgres.
When adding a third node that participates in the quorum (one primary, two secondaries), the setting is automatically changed from zero to one.