# Multiple Sombra Clusters (/docs/sombra/deploying/customizing-sombra/multiple-sombras)

Most customers only need to deploy one Sombra cluster. However, there are cases where it makes sense to deploy multiple clusters:

- If your organization uses a hybrid cloud, you may wish to deploy one Sombra in each cloud environment and one Sombra in your on-prem environment
- If your organization uses multiple cloud providers, you may wish to deploy one Sombra cluster in each cloud environment.
- If your organization employs multiple VPCs that you want to keep separate, you may map one Sombra cluster to each VPC. Alternatively, you could apply [VPC Network Peering](https://www.kentik.com/kentipedia/what-is-vpc-peering/) to give one Sombra cluster access to resources across multiple VPCs.

<Callout type="info">
  **Looking for auto-scaling within a cluster?**

  This guide is specific to deploying multiple Sombra _clusters_. If you are looking for information about adding additional Sombra nodes within a cluster, please refer to [this guide](../../architecture.mdx#sombra-is-highly-available).
</Callout>

### How to specify your primary Sombra cluster [#how-to-specify-your-primary-sombra-cluster]

If you choose to deploy multiple Sombra clusters, you will need to specify the primary Sombra cluster [in the Admin Dashboard](https://app.transcend.io/infrastructure/sombra/sombras). By default, your integrations will route through your primary Sombra cluster.

![Setting the primary Sombra](/images/screenshot/2025-03-14-primary-sombra.png)

### Configuration requirements for multiple Sombra setups [#configuration-requirements-for-multiple-sombra-setups]

#### SOMBRA_ID [#sombra_id]

For each self-hosted Sombra cluster, you will need to retrieve the Sombra ID from the [Admin Dashboard -> Sombra settings](https://app.transcend.io/infrastructure/sombra/sombras), and set the `SOMBRA_ID` environment variable to it within the Docker container that is running Sombra.

![Getting a Sombra ID](/images/screenshot/2025-03-14-getting-the-sombra-id.png)

#### JWT_ECDSA_KEY [#jwt_ecdsa_key]

The environment variable `JWT_ECDSA_KEY` should be set to the same value for each Sombra cluster.

#### CONSENT_IDENTIFIER_ENCRYPTION_KEY [#consent_identifier_encryption_key]

If you use Preference Management across multiple Sombra clusters, the environment variable `CONSENT_IDENTIFIER_ENCRYPTION_KEY` should be set to the same value for each Sombra cluster. This key encrypts and decrypts consent identifiers; mismatched keys prevent Sombra from decrypting identifiers when querying preferences. See [Consent Identifier Encryption Key](../../environment-variables.mdx#consent-identifier-encryption-key) for details.

### Specifying which integrations route to different Sombra Gateways [#specifying-which-integrations-route-to-different-sombra-gateways]

In the Admin UI, use the `Associated Integrations` dropdown in the Admin Dashboard to select which integrations should route to your non-primary Sombra cluster(s).

Alternatively, you can specify which Sombra cluster each integration should route through using the `sombra_id` parameter in [Terraform](https://registry.terraform.io/providers/transcend-io/transcend/latest/docs/resources/data_silo). The value for `sombra_id` can be obtained in the Admin Dashboard.