Multi-Cluster Ops Manager Architecture

Single- and Multi-Cluster Mode

The following settings in the Ops Manager Resource Specification define the mode in which you deploy the Ops Manager Application and the Application Database custom resources:

• Multi-cluster mode. To deploy the Ops Manager Application and the Application Database on multiple Kubernetes clusters, set spec.topology and spec.applicationDatabase.topology to MultiCluster.

  If you define spec.topology and spec.applicationDatabase.topology as MultiCluster, this allows you to begin with a single-member Kubernetes cluster and scale your multi-cluster deployment as needed. In particular:

  • You can create a deployment in a multi-cluster mode that has only one member cluster.

  • You can have the replica set of a minimum 3 mongod processes for the Application Database deployed on a single member cluster in a multi-cluster mode. To increase resilience of the Application Database, you can expand the replica set to span across multiple Kubernetes clusters and redeploy the configuration.

  • You can have a single Ops Manager Application instance deployed on a single member cluster in a multi-cluster mode. To increase resilience of the Ops Manager Application, you can add more Kubernetes clusters, add the Ops Manager Application instances on them and redeploy the configuration.

• Single cluster mode. To deploy the Ops Manager Application and the Application Database on a single Kubernetes cluster, omit specifying the values for the following settings, or set spec.topology and spec.applicationDatabase.topology to SingleCluster.

Limitations

Deploying the Ops Manager Application and the Application Database on multiple Kubernetes clusters has the following limitations:

• You can't change the topology of an existing Ops Manager deployment from single to multi-cluster. You can set spec.topology and spec.applicationDatabase.topology to MultiCluster only for new deployments of the Ops Manager Application.

• You can't use the Kubernetes Operator to deploy the Ops Manager Application and the Application Database without a service mesh. To learn more, see Service Mesh.

• You can't use HashiCorp Vault in any multi-cluster Kubernetes deployments. This includes multi-cluster deployments of Ops Manager resources, the Application Database resources, and MongoDBMultiCluster resources.

Differences between Single and Multi-Cluster Ops Manager Deployments

The following table lists the differences between single and multi-Kubernetes cluster deployments of the Ops Manager Application and the Application Database. All other features not listed in this table are equivalent for single and multi-cluster deployments.

Use the following resources to help you learn about the architecture and performance of a multi-Kubernetes cluster deployment, and to configure networking:

• Architecture Diagram

• Networking, Load Balancer, Service Mesh

• Performance