# Nais Postgres reference > **Experimental feature** > This feature is an alpha feature, and is subject to API change, instability or removal. > See the [main Postgres page](/persistence/postgres.md) for more information. This document describes all possible configuration values in the `Postgres` spec, commonly known as the `postgres.yaml` file. A `Postgres` is a logical database: pgrator creates its default `main` branch as a separate CNPG cluster. `spec.activeBranch` requests a local branch name; `status.activeBranch` is the observed selection. A requested branch must have an initialized, Ready, non-terminating CNPG cluster before pgrator updates observed status. This check is not an atomic cutover guarantee; verify workload connections when switching branches. ## activeBranch ActiveBranch selects the local branch name within this Postgres for normal workloads. When omitted, pgrator retains the current active branch. Type: `string`
Required: `false`
> **Example** > ```yaml > spec: > activeBranch: main > ``` ## extensions Extensions mounts additional extension images from the configured CNPG image catalog. Extensions bundled with the Postgres image do not need to be listed here. Mounting an extension does not activate it in a database; use CREATE EXTENSION separately. Type: `array`
Required: `false`
> **Example** > ```yaml > spec: > extensions: > - name: postgis > ``` ### extensions[].name Name of the extension image to mount from the configured CNPG image catalog. Type: `enum`
Required: `true`
Allowed values: `postgis`, `timescaledb-oss`
> **Example** > ```yaml > spec: > extensions: > - name: postgis > ``` ## highAvailability HighAvailability adds a third instance and enables synchronous replication. A cluster always runs a primary and a standby, so failover is available either way. What this adds is the guarantee that an acknowledged commit survives losing the primary, at the cost of write latency. Type: `boolean`
Required: `false`
> **Example** > ```yaml > spec: > highAvailability: true > ``` ## majorVersion MajorVersion of Postgres to use. Type: `enum`
Required: `true`
Allowed values: `18`
> **Example** > ```yaml > spec: > majorVersion: "18" > ``` ## resources Resources configures compute and disk for the Postgres cluster. Type: `object`
Required: `false`
> **Example** > ```yaml > spec: > resources: > cpu: 100m > diskSize: 10Gi > memory: 512Mi > ``` ### resources.cpu Cpu is the CPU resources for the Postgres cluster. Type: `integer` or `string`
Required: `false`
Pattern: `^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$`
> **Example** > ```yaml > spec: > resources: > cpu: 100m > ``` ### resources.diskSize DiskSize is the disk size for the Postgres cluster. Type: `integer` or `string`
Required: `false`
Pattern: `^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$`
> **Example** > ```yaml > spec: > resources: > diskSize: 10Gi > ``` ### resources.memory Memory is the memory resources for the Postgres cluster. Type: `integer` or `string`
Required: `false`
Pattern: `^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$`
> **Example** > ```yaml > spec: > resources: > memory: 512Mi > ```