# 2 — Persistence

The offline store, online store, and registry each need a place to store data. The operator supports two persistence patterns for each:

* **File persistence** — a path on a volume (ephemeral or PVC-backed)
* **DB/store persistence** — an external database or managed store, wired via a Kubernetes Secret

The pattern is the same for all three services; only the store types differ.

***

## Persistence patterns at a glance

| Pattern                 | Best for                    | Data survives pod restart? |
| ----------------------- | --------------------------- | -------------------------- |
| **File — emptyDir**     | Dev / CI                    | No                         |
| **File — PVC (ref)**    | Single-node prod or testing | Yes (if PVC is retained)   |
| **File — PVC (create)** | Operator-managed storage    | Yes                        |
| **DB store**            | Production, HA, multi-pod   | Yes                        |

***

## File persistence

### Ephemeral (emptyDir)

The default when no `persistence` block is set. Data lives on the pod's local disk and is lost on restart. Suitable for development only.

```yaml
services:
  onlineStore:
    server: {}          # no persistence block → emptyDir
```

### PVC — reference an existing PVC

When you already have a PVC provisioned (e.g. by your storage team):

```yaml
services:
  onlineStore:
    persistence:
      file:
        path: online_store.db          # filename relative to mountPath
        pvc:
          ref:
            name: online-pvc           # name of the existing PVC
          mountPath: /data/online      # where the PVC is mounted in the pod
```

### PVC — let the operator create one

```yaml
services:
  offlineStore:
    persistence:
      file:
        type: duckdb                   # offline file type: file | dask | duckdb
        pvc:
          create:
            storageClassName: standard
            resources:
              requests:
                storage: 20Gi
          mountPath: /data/offline
```

Omitting `storageClassName` uses the cluster default StorageClass. Omitting `create` entirely creates a PVC with the operator's built-in defaults (1 Gi, default StorageClass).

```yaml
registry:
  local:
    persistence:
      file:
        path: registry.db
        pvc:
          create: {}                   # operator defaults: 1 Gi, default StorageClass
          mountPath: /data/registry
```

***

## DB / store persistence

For production, point the operator at an external database. The operator reads connection details from a Kubernetes Secret and writes them into `feature_store.yaml`.

### Secret format

The Secret must contain one key per store component. The **key name** is the store type (e.g. `postgres`, `sql`, `redis`). The **value** is a YAML snippet identical to what you would write under the corresponding section in `feature_store.yaml`, **minus the `type:` key** (the operator inserts it from `persistence.store.type`).

```yaml
apiVersion: v1
kind: Secret
metadata:
  name: feast-data-stores
stringData:
  # Key for online store type "postgres"
  postgres: |
    host: postgres.feast.svc.cluster.local
    port: 5432
    database: feast
    db_schema: public
    user: feast
    password: feast

  # Key for registry type "sql" (SQLAlchemy URL)
  sql: |
    path: postgresql+psycopg://feast:feast@postgres.feast.svc.cluster.local:5432/feast  #pragma: allowlist secret
    cache_ttl_seconds: 60
    sqlalchemy_config_kwargs:
      echo: false
      pool_pre_ping: true
```

Reference the Secret from the CR:

```yaml
services:
  onlineStore:
    persistence:
      store:
        type: postgres
        secretRef:
          name: feast-data-stores      # key "postgres" is read automatically
  registry:
    local:
      persistence:
        store:
          type: sql
          secretRef:
            name: feast-data-stores    # key "sql" is read automatically
```

> **Key lookup rule**: the operator looks up the Secret key that matches `persistence.store.type` (e.g. `type: postgres` → key `postgres`). Keep all stores in one Secret or split across multiple — both work.

### Injecting DB credentials into the server pod

The Secret key values in the example above hard-code passwords. For production, keep credentials in a separate Secret and inject them as environment variables using `envFrom`, then reference them with `${VAR}` substitution in the data-stores Secret value:

```yaml
apiVersion: v1
kind: Secret
metadata:
  name: postgres-creds
stringData:
  POSTGRES_USER: feast
  POSTGRES_PASSWORD: s3cr3t
---
apiVersion: v1
kind: Secret
metadata:
  name: feast-data-stores
stringData:
  postgres: |
    host: postgres.feast.svc.cluster.local
    port: 5432
    database: feast
    user: ${POSTGRES_USER}
    password: ${POSTGRES_PASSWORD}
```

```yaml
services:
  onlineStore:
    server:
      envFrom:
        - secretRef:
            name: postgres-creds      # expands ${POSTGRES_USER} / ${POSTGRES_PASSWORD}
    persistence:
      store:
        type: postgres
        secretRef:
          name: feast-data-stores
```

***

## Store types by component

### Online store

| `type`      | Secret key  | SDK docs                                                                                                                  |
| ----------- | ----------- | ------------------------------------------------------------------------------------------------------------------------- |
| `sqlite`    | `sqlite`    | [SQLite](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/sqlite.md)       |
| `redis`     | `redis`     | [Redis](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/redis.md)         |
| `postgres`  | `postgres`  | [Postgres](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/postgres.md)   |
| `cassandra` | `cassandra` | [Cassandra](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/cassandra.md) |
| `hazelcast` | `hazelcast` | [Hazelcast](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/hazelcast.md) |
| `hbase`     | `hbase`     | [HBase](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/hbase.md)         |
| `datastore` | `datastore` | [Datastore](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/datastore.md) |
| `dynamodb`  | `dynamodb`  | [DynamoDB](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/dynamodb.md)   |
| `bigtable`  | `bigtable`  | [Bigtable](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/bigtable.md)   |

> For all store-specific YAML keys (connection options, pool sizes, etc.) see the linked SDK docs — the Secret value accepts the same keys.

### Offline store

| `type` (file) | Notes                                      |
| ------------- | ------------------------------------------ |
| `file`        | Default pandas-based parquet offline store |
| `dask`        | Dask-based parallel parquet                |
| `duckdb`      | DuckDB in-process analytical engine        |

For external DB-backed offline stores (BigQuery, Snowflake, Spark, Trino, etc.), use `persistence.store.type` and a Secret with the matching key. See [Offline Stores](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/offline-stores/README.md) in the SDK docs.

### Registry

| `type`               | Secret key                      | Notes                                               |
| -------------------- | ------------------------------- | --------------------------------------------------- |
| `file`               | *(file persistence, no Secret)* | SQLite-backed file registry                         |
| `sql`                | `sql`                           | SQLAlchemy URL — supports PostgreSQL, MySQL, SQLite |
| `snowflake.registry` | `snowflake.registry`            | Snowflake-backed registry                           |

For `sql`, the Secret value is a `path:` (SQLAlchemy URL) plus optional `cache_ttl_seconds` and `sqlalchemy_config_kwargs`:

```yaml
# feast-data-stores Secret, key "sql"
sql: |
  path: postgresql+psycopg://user:pass@host:5432/feast  #pragma: allowlist secret
  cache_ttl_seconds: 60
```

***

## Common patterns

### Redis online store

```yaml
apiVersion: v1
kind: Secret
metadata:
  name: feast-data-stores
stringData:
  redis: |
    connection_string: redis.feast.svc.cluster.local:6379
---
apiVersion: feast.dev/v1
kind: FeatureStore
metadata:
  name: sample-redis
spec:
  feastProject: my_project
  services:
    onlineStore:
      server: {}
      persistence:
        store:
          type: redis
          secretRef:
            name: feast-data-stores
```

### Postgres for both online store and registry

```yaml
services:
  onlineStore:
    persistence:
      store:
        type: postgres
        secretRef:
          name: feast-data-stores     # reads key "postgres"
  offlineStore:
    persistence:
      file:
        type: duckdb
        pvc:
          create: {}
          mountPath: /data/offline
  registry:
    local:
      persistence:
        store:
          type: sql
          secretRef:
            name: feast-data-stores   # reads key "sql"
```

***

## See also

* [API reference — `OnlineStorePersistence`](https://github.com/feast-dev/feast/blob/stable/infra/feast-operator/docs/api/markdown/ref.md#onlinestorepersistence)
* [API reference — `OfflineStorePersistence`](https://github.com/feast-dev/feast/blob/stable/infra/feast-operator/docs/api/markdown/ref.md#offlinepersistence)
* [API reference — `RegistryPersistence`](https://github.com/feast-dev/feast/blob/stable/infra/feast-operator/docs/api/markdown/ref.md#registrypersistence)
* [Sample: DB persistence (Postgres)](https://github.com/feast-dev/feast/blob/stable/infra/feast-operator/config/samples/v1_featurestore_db_persistence.yaml)
* [Sample: PVC persistence](https://github.com/feast-dev/feast/blob/stable/infra/feast-operator/config/samples/v1_featurestore_pvc_persistence.yaml)
* [Sample: object store (GCS)](https://github.com/feast-dev/feast/blob/stable/infra/feast-operator/config/samples/v1_featurestore_gcs.yaml)
* [Feast SDK — Online Stores](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/online-stores/README.md)
* [Feast SDK — Offline Stores](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/offline-stores/README.md)
* [Feast SDK — Registries](https://github.com/feast-dev/feast/blob/v0.63-branch/docs/how-to-guides/reference/registries/README.md)


---

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