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opentf/website/docs/language/settings/backends/pg.html.md
Chris Arcand f521ba6cd7 Remove 'enhanced' backend type distinction
As explained in the changes: The 'enhanced' backend terminology, which
only truly pertains to the 'remote' backend with a single API (Terraform
Cloud/Enterprise's), has been found to be a confusing vestige which need
only be explained in the context of the 'remote' backend.

These changes reorient the explanation(s) of backends to pertain more
directly to their primary purpose, which is storage of state snapshots
(and not implementing operations).

That Terraform operations are still _implemented_ by the literal
`Backend` and `Enhanced` interfaces is inconsequential a user of
Terraform, an internal detail.
2021-12-07 16:29:51 -06:00

3.6 KiB

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language Backend Type: pg docs-backends-types-standard-pg Terraform can store state remotely in a Postgres database with locking.

pg

Stores the state in a Postgres database version 10 or newer.

This backend supports state locking.

Example Configuration

terraform {
  backend "pg" {
    conn_str = "postgres://user:pass@db.example.com/terraform_backend"
  }
}

Before initializing the backend with terraform init, the database must already exist:

createdb terraform_backend

This createdb command is found in Postgres client applications which are installed along with the database server.

We recommend using a partial configuration for the conn_str variable, because it typically contains access credentials that should not be committed to source control:

terraform {
  backend "pg" {}
}

Then, set the credentials when initializing the configuration:

terraform init -backend-config="conn_str=postgres://user:pass@db.example.com/terraform_backend"

To use a Postgres server running on the same machine as Terraform, configure localhost with SSL disabled:

terraform init -backend-config="conn_str=postgres://localhost/terraform_backend?sslmode=disable"

Data Source Configuration

To make use of the pg remote state in another configuration, use the terraform_remote_state data source.

data "terraform_remote_state" "network" {
  backend = "pg"
  config = {
    conn_str = "postgres://localhost/terraform_backend"
  }
}

Configuration Variables

The following configuration options or environment variables are supported:

  • conn_str - (Required) Postgres connection string; a postgres:// URL
  • schema_name - Name of the automatically-managed Postgres schema, default terraform_remote_state.
  • skip_schema_creation - If set to true, the Postgres schema must already exist. Terraform won't try to create the schema, this is useful when it has already been created by a database administrator.
  • skip_table_creation - If set to true, the Postgres table must already exist. Terraform won't try to create the table, this is useful when it has already been created by a database administrator.
  • skip_index_creation - If set to true, the Postgres index must already exist. Terraform won't try to create the index, this is useful when it has already been created by a database administrator.

Technical Design

This backend creates one table states in the automatically-managed Postgres schema configured by the schema_name variable.

The table is keyed by the workspace name. If workspaces are not in use, the name default is used.

Locking is supported using Postgres advisory locks. force-unlock is not supported, because these database-native locks will automatically unlock when the session is aborted or the connection fails. To see outstanding locks in a Postgres server, use the pg_locks system view.

The states table contains:

  • a serial integer id, used as the key for advisory locks
  • the workspace name key as text with a unique index
  • the Terraform state data as text