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Percona Operators Documentation

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Plan your multi-cluster or multi-region deployment

Requirements

Regardless of topology, successful deployments share several technical requirements:

  • Network connectivity: Every node in both the Main and the Replica sites must be able to reach each other over the network, like in full mesh:

    image

    To make this happen in Kubernetes clusters, you need to expose all Replica Set nodes (including Config Servers) on both sites through a dedicated Service. To learn more, see the Service per Pod section in the Exposing the cluster chapter.

  • User credentials must be the same in both clusters.

  • TLS certificates must be the same in both clusters.

You must have a single Main cluster but you can have multiple Replica clusters as long as you don’t have more than 50 members in the Replica Set. This limitation comes from MongoDB itself, for more information please check MongoDB documentation .

Topologies

The Operator automates configuration of Main and Replica MongoDB sites when you run them on Kubernetes. However, multi-cluster or multi-region deployment is not bound to Kubernetes. Either Main or Replica can run outside of Kubernetes, be regular MongoDB and be out of the Operator’s control.

The following topologies are supported:

Main and Replica clusters on Kubernetes.

This is the Kubernetes-native deployment. You can automate the cluster management using the Multi-Cluster Services.

The Deployment section focuses on this topology and provides the setup steps.

Main cluster on Kubernetes and Replica cluster outside of Kubernetes.

You can deploy or reuse an existing cluster on Kubernetes as the Main site and have the Replica cluster outside of Kubernetes.

The setup steps are:

  1. Deploy the Main cluster on a Kubernetes cluster (or use an existing one)
  2. Export TLS certificates and user Secrets from the main site and use them to configure the Replica site.
  3. Deploy the Replica cluster wherever you want.
  4. Interconnect sites by adding nodes from the Replica cluster to the Main cluster as external nodes.

Main cluster outside of Kubernetes and Replica cluster on Kubernetes

You can deploy or reuse an existing cluster outside of Kubernetes as the Main site and run the Replica cluster on Kubernetes.

The setup steps are:

  1. Deploy the Main cluster wherever you want (or use an existing one)
  2. Export the TLS certificates and user credentials from the main site.
  3. Create the Kubernetes Secrets objects: for TLS certificates and for User secrets. You will use these Secrets to deploy the Replica site.
  4. Deploy the Replica cluster on a Kubernetes cluster using the Secrets you created.
  5. Interconnect sites by adding nodes from the Replica cluster to the Main cluster using the MongoDB client.

Next steps

Multi-cluster services Deploy the Main site

Last update: 2025-10-01