[Yandex Cloud documentation](../../index.md) > [Yandex StoreDoc](../index.md) > [Step-by-step guides](index.md) > Sharding and replication > Primary replica failover

# Primary replica failover

In a cluster with [multiple replicas](../concepts/replication.md), you can switch the primary replica if needed.

The switchover typically takes less than a minute. During the switchover, the cluster may be unwriteable for a few seconds.


{% list tabs group=instructions %}

- Management console {#console}

    1. Open the [folder dashboard](https://console.yandex.cloud).
    1. Navigate to **Yandex StoreDoc**.
    1. Click the name of your cluster and select the **Hosts** tab.
    1. Locate the `PRIMARY` host in the list, click ![options](../../_assets/console-icons/ellipsis.svg) in its row, and select **Step down**.

- CLI {#cli}

    If you do not have the Yandex Cloud CLI yet, [install and initialize it](../../cli/quickstart.md#install).

    The folder used by default is the one specified when [creating](../../cli/operations/profile/profile-create.md) the CLI profile. To change the default folder, use the `yc config set folder-id <folder_ID>` command. You can also specify a different folder for any command using `--folder-name` or `--folder-id`. If you access a resource by its name, the search will be limited to the default folder. If you access a resource by its ID, the search will be global, i.e., through all folders based on access permissions.

    To perform a primary replica switchover, run this command:

    ```bash
    yc managed-mongodb hosts stepdown <current_primary_replica_name> \
       --name=<cluster_name>
    ```

    You can get the primary replica name for the required shard from the [cluster’s host list](hosts.md#list), and the cluster name from the [list of clusters in your folder](cluster-list.md#list-clusters).

- REST API {#api}

    1. [Get an IAM token for API authentication](../api-ref/authentication.md) and put it into an environment variable:

        ```bash
        export IAM_TOKEN="<IAM_token>"
        ```

    1. Call the [Cluster.StepdownHosts](../api-ref/Cluster/stepdownHosts.md) method, e.g., via the following [cURL](https://curl.se/) request:

        ```bash
        curl \
            --request POST \
            --header "Authorization: Bearer $IAM_TOKEN" \
            --header "Content-Type: application/json" \
            --url 'https://mdb.api.cloud.yandex.net/managed-mongodb/v1/clusters/<cluster_ID>:stepdownHosts' \
            --data '{
                     "hostNames": [
                        "<current_primary_replica_name>"
                     ]
                    }'
        ```

        You can get the cluster ID from the [list of clusters in your folder](cluster-list.md#list-clusters), and the primary replica name for the required shard from the [cluster’s host list](hosts.md#list).

    1. Check the [server response](../api-ref/Cluster/stepdownHosts.md#yandex.cloud.operation.Operation) to make sure your request was successful.

- gRPC API {#grpc-api}

    1. [Get an IAM token for API authentication](../api-ref/authentication.md) and put it into an environment variable:

        ```bash
        export IAM_TOKEN="<IAM_token>"
        ```

    1. Clone the [cloudapi](https://github.com/yandex-cloud/cloudapi) repository:
       
       ```bash
       cd ~/ && git clone --depth=1 https://github.com/yandex-cloud/cloudapi
       ```
       
       Below, we assume that the repository contents reside in the `~/cloudapi/` directory.

    1. Call the [ClusterService.StepdownHosts](../api-ref/grpc/Cluster/stepdownHosts.md) method, e.g., via the following [gRPCurl](https://github.com/fullstorydev/grpcurl) request:

        ```bash
        grpcurl \
            -format json \
            -import-path ~/cloudapi/ \
            -import-path ~/cloudapi/third_party/googleapis/ \
            -proto ~/cloudapi/yandex/cloud/mdb/mongodb/v1/cluster_service.proto \
            -rpc-header "Authorization: Bearer $IAM_TOKEN" \
            -d '{
                 "cluster_id": "<cluster_ID>",
                 "host_names": [
                    "<current_primary_replica_name>"
                 ]
                }' \
            mdb.api.cloud.yandex.net:443 \
            yandex.cloud.mdb.mongodb.v1.ClusterService.StepdownHosts
        ```    

        You can get the cluster ID from the [list of clusters in your folder](cluster-list.md#list-clusters), and the primary replica name for the required shard from the [cluster’s host list](hosts.md#list).

    1. Check the [server response](../api-ref/grpc/Cluster/stepdownHosts.md#yandex.cloud.operation.Operation) to make sure your request was successful.

{% endlist %}