Cluster Linking with Private Networking

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Supported Cluster Combinations

Cluster Linking is fundamentally a networking feature: it copies data over the network. As such, Cluster Linking requires that at least one of the clusters involved has connectivity to the other cluster. Therefore, the networking situation of each cluster determines whether the two clusters can be linked, and whether the destination cluster or the source cluster must initiate the connection. By default, the destination cluster will initiate the connection. A special mode called “source-initiated links” allows the source cluster to initiate the connection of the cluster link.

The following tables show which networking combinations are possible, and whether a source-initiated link is required.

Tip

When using the Confluent Cloud Console to create cluster links, only linkable clusters are shown in the drop-down options. Clusters that cannot be linked are filtered out.

Confluent Cloud Source and Destination Clusters

Source cluster Destination cluster Possible? Notes
Confluent Cloud - A Basic or Standard cluster, or a Dedicated [1] cluster with Internet networking Confluent Cloud - Any Dedicated cluster Yes  
Confluent Cloud - A cluster with private networking Confluent Cloud - A Dedicated cluster in the same Confluent Cloud network Yes  
Confluent Cloud - A Dedicated cluster with Transit Gateway networking Confluent Cloud - A Dedicated cluster with Transit Gateway networking Yes (in Preview) [2]
  • Contact Confluent Support or your Confluent Account Team
  • Requires proper Transit Gateway configuration
  • Neither cluster can use the CIDR 198.18.0.0/15
Confluent Cloud - A cluster with private networking Confluent Cloud - A cluster with private networking in a different Confluent Cloud network No (except the Transit Gateway case above)  
Confluent Cloud - A cluster with private networking Confluent Cloud - A Dedicated cluster with public networking Yes (in Preview) [2]
  • Must use a source-initiated link
[1]Basic, Standard, and Dedicated cluster types are described in Supported Cluster Types.
[2](1, 2, 3, 4) Preview scenarios are for testing and evaluation purposes or to give feedback to Confluent. They are not suitable for production use cases and do not fall into any Confluent Support SLAs.

Confluent Platform and Confluent Cloud

Source cluster Destination cluster Possible? Notes
Confluent Platform 7.1.0 or later Confluent Cloud - Any Dedicated cluster Yes
  • Must use a source-initiated link
  • Source Confluent Platform cluster must have connectivity to the destination cluster
  • Brokers must be Confluent Server
Confluent Platform 5.4 to 7.0 with public endpoints on all brokers Confluent Cloud - Any Dedicated cluster Yes
  • If the Confluent Cloud cluster has static egress IPs, a firewall in front of Confluent Platform can filter on those IPs
  • Cluster link must use SASL/PLAIN, SASL/SCRAM, and/or mTLS
Confluent Platform 5.4 to 7.0 without public endpoints Confluent Cloud - A Dedicated cluster with private networking (all networking types) Yes (in Preview) [2]
  • Contact Confluent Support or your Confluent Account Team
  • Destination Confluent Cloud cluster must have connectivity to the source Confluent Cloud cluster
  • Cluster link must use SASL/PLAIN, SASL/SCRAM, and/or mTLS
Confluent Cloud - A Basic or Standard cluster, or a Dedicated cluster with Internet networking Confluent Platform 7.0.0 or later Yes  
Confluent Cloud - A cluster with private networking Confluent Platform 7.0.0 or later Yes
  • Destination Confluent Cloud cluster must have connectivity to the source Confluent Cloud cluster

Confluent Cloud and Apache Kafka®

Source cluster Destination cluster Possible? Notes
Kafka 2.4 or later with public endpoints on all brokers Confluent Cloud - Any Dedicated cluster Yes
  • If the Confluent Cloud cluster has static egress IPs, a firewall in front of Kafka can filter on those IPs
  • Cluster link must use SASL/PLAIN, SASL/SCRAM, and/or mTLS
Kafka 2.4 or later without public endpoints Confluent Cloud - A Dedicated cluster with private networking (all networking types) Yes (in Preview) [2]
  • Contact Confluent Support or your Confluent Account Team
  • Destination Confluent Cloud cluster must have connectivity to the source Kafka cluster

Diagrams of Supported Combinations for Private Networking

Confluent Cloud to Confluent Cloud

../../_images/cluster-link-private-net-cloud-to-cloud.png

Confluent Cloud to Confluent Platform/Apache Kafka®

../../_images/cluster-link-private-net-cloud-to-cp-kafka.png

Confluent Cloud Billing Considerations

There are cost differences associated with private vs. public networking. These are detailed under Cluster Linking in the Billing documentation. Examples are provided there for public networking, with more details about private networking to follow soon.