# Postgres reference > **Preview** > Postgres is in preview. Use it with care; the API and supported workflows may change. > See the [Postgres overview](/persistence/postgres.md) for current availability. This document describes the configuration values in the `Postgres` spec, commonly known as the `postgres.yaml` file. Each `Postgres` starts with a branch named `main`. `spec.activeBranch` selects the branch for workloads without an explicit `uses.postgres[].branch`; `status.activeBranch` reports the branch that is active now. Switching branches is not instant. See [Postgres branches](/persistence/postgres/explanations/branches.md) for the branch model. ## 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 to enable in the Postgres database. See [available extensions](/persistence/postgres/reference/extensions.md) for names included in the PostgreSQL image. Type: `array`
Required: `false`
> **Example** > ```yaml > spec: > extensions: > - name: vector > ``` ### extensions[].name Name of the Postgres extension to enable. Type: `string`
Required: `true`
> **Example** > ```yaml > spec: > extensions: > - name: vector > ``` ## 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. Only PostgreSQL 18 is available in preview. The schema also accepts 16 and 17, but the platform image catalog does not provide those versions. Type: `enum`
Required: `true`
Allowed values: `16`, `17`, `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. Use CPU cores or millicores: `1` is one core, `500m` is half a core, and `100m` is one tenth of a core. Type: `integer` or `string`
Required: `false`
> **Validation pattern** > ```regex > ^(\+|-)?(([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. Use a Kubernetes quantity, for example `10Gi` (10 gibibytes) or `100Gi`. Disk size can only increase. Type: `integer` or `string`
Required: `false`
> **Validation pattern** > ```regex > ^(\+|-)?(([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. Use a Kubernetes quantity, for example `512Mi` (512 mebibytes) or `1Gi` (1 gibibyte). Type: `integer` or `string`
Required: `false`
> **Validation pattern** > ```regex > ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$ > ``` > **Example** > ```yaml > spec: > resources: > memory: 512Mi > ```