Cluster peering overview

This topic provides an overview of cluster peering, a feature that connects two or more independent clusters so that services deployed to different partitions or datacenters can communicate.

Introduction

If you have HCP Consul Dedicated clusters, you can create cluster peering connections within the same HVN, or between clusters hosted on two different HVNs or cloud providers.

You can use the HCP UI to peer HCP Consul Dedicated clusters in the same HCP project.

For more information about cluster peering, including general usage and Kubernetes-specific information, refer to the cluster peering overview in the Consul documentation.

Multi-region and multi-cloud support

The HCP cluster tier determines whether the Consul cluster can peer to clusters across multiple regions or clouds.

For testing purposes, the development tier supports all cluster peering features. To use cluster peering in production environments, you must have an annual subscription through either an annual entitlement contract or Flex billing.

For more information about how tiers differ in their support for multi-region and multi-cloud cluster peering, refer to HCP Consul Dedicated tiers. For information about the features available on each tier, refer to HCP Consul features.

Tier limitations

When using cluster peering, be aware of the following limitations and technical constraints.

• Cluster peering in production environments requires an account with either an annual entitlement contract or Flex billing. Refer to billing models for more information.
• Premium tier clusters are only available with annual entitlement contracts and Flex billing subscriptions.
• Plus tier clusters in Azure are only available with annual entitlement contracts and Flex billing subscriptions.

Cluster peering and WAN federation

As described in the Consul documentation, cluster peering treats each datacenter as a separate cluster, while WAN federation connects multiple datacenters to make them function as if they were a single cluster. As a result, WAN federation requires a primary datacenter to maintain and replicate global states such as ACLs and configuration entries, but cluster peering does not.

HCP does not support WAN federation in Azure environments. As a result, it is not possible to connect HCP Consul Dedicated clusters hosted on AWS and Azure with WAN federation. You also cannot federate HCP Consul Dedicated and self-managed Community and Enterprise clusters. However, HCP Consul Dedicated supports cluster peering between AWS and Azure clusters, as well as cluster peering between HCP Consul Dedicated and self-managed Community and Enterprise clusters.

Constraints and considerations

Cluster peering has the following constraints:

• The clusters must run Consul v1.14.2 or later.
• When you create a cluster peering connection externally, the connection can still operate but it cannot be edited to make it appear on the HCP platform.