Confluent Cloud Private Link: Secure, Private, and Simplified Networking for Modern Data Pipelines
As organizations continue shifting toward fully managed cloud data platforms, network security and connectivity architecture have become core priorities. Confluent Cloud—powered by Apache Kafka—addresses these challenges by deeply integrating with Private Link technologies from AWS, Azure, and Google Cloud. By using Private Link, Confluent Cloud enables fully private, non-internet-exposed connections between customer environments and Kafka clusters. In this article, we explore how Confluent Cloud uses inbound and outbound Private Link endpoints, along with its Private Link Service (PLS), to deliver secure, compliant, and simplified data connectivity. What Is Private Link and Why It Matters Private Link technologies—including AWS PrivateLink, Azure Private Link, and GCP Private Service Connect (PSC)—allow organizations to establish direct, private communication paths between their VPCs/VNets and external cloud services. For Confluent Cloud users, this means Kafka clusters and connected systems can communicate without ever traversing the public internet. The result: reduced risk, simplified networking, and streamlined compliance. Important Note on Connectivity Options While Private Link provides service-level connectivity, Confluent Cloud also supports alternative private networking approaches for different architectural needs: VPC Peering: Offers full bidirectional connectivity but requires CIDR coordination AWS Transit Gateway: Simplifies multi-VPC architectures by acting as a cloud router; popular for large-scale deployments GCP VPC Peering: Similar to AWS peering for Google Cloud environments Private Link provides unidirectional, service-specific connectivity, making it ideal for organizations requiring strict access controls and simplified network architecture. Inbound Private Link Endpoints Inbound Private Link endpoints give customer applications a private IP path to Confluent Cloud Kafka clusters from within their own VPC or VNet. Why This Matters Secure Access – No public endpoints or public IP exposure Reduced Attack Surface – All traffic remains on the cloud provider’s private backbone Simplified Networking Across Regions – Eliminates the need for VPC peering, complex routing, or VPN setups Lower Latency & Higher Throughput – Direct connectivity through Private Link often results in measurably lower latency and higher throughput compared to public endpoints or complex routing architectures, improving application performance Inbound Private Link is the recommended method for securely connecting applications to Confluent Cloud. Outbound Private Link Endpoints Outbound endpoints allow Confluent Cloud services—such as managed connectors, ksqlDB, and other data processing components—to privately access systems running inside a customer’s environment. Why This Matters Secure Integration – Private access to internal databases, APIs, and applications Multi-Cloud Consistency – Works across AWS, Azure, and GCP with a uniform model. Confluent Cloud now supports cross-cloud Cluster Linking with private networking across AWS, Azure, and Google Cloud, enabling multi-region and multi-cloud strategies Compliance-Friendly – Sensitive data stays private and never requires public exposure Granular Access Control – Private Link provides granular mapping of endpoints to specific resources, restricting access to only the mapped service. In a security incident, only that specific resource would be accessible, not the entire peered network Important Operational Details Managed Connectors: Can use Egress Private Link Endpoints to access private internal systems, but they can still use public IP addresses to connect to public endpoints when Egress Private Link isn’t configured ksqlDB Provisioning: New ksqlDB instances require internet access for provisioning; they become fully accessible over Private Link connections once provisioned Schema Registry Internet Access: Confluent Cloud Schema Registry remains partially accessible over the internet even when Private Link is configured. Specifically, internal Confluent components (fully-managed connectors, Flink SQL, and ksqlDB) continue to access Schema Registry through the public internet using uniquely identified traffic that bypasses IP filtering policies. This must be accounted for in security and firewall planning Outbound Private Link is particularly valuable when connectors need to interact with internal databases or APIs securely. Private Link Service: The Core of the Architecture At the center of Confluent’s Private Link implementation is the Private Link Service (PLS). This service: Privately exposes Kafka clusters through endpoint connections Maps customer endpoints to Confluent-managed infrastructure using SNI (Server Name Indication) routing at Layer 7 Maintains stable, resilient connectivity even as brokers scale or rotate through SNI-based traffic routing, ensuring connectivity remains stable even when brokers are replaced or the underlying infrastructure changes PLS supports both inbound and outbound Private Link connections, ensuring a unified private networking model. Architecture Overview The flow below illustrates how Confluent Cloud’s Private Link model works end-to-end: All traffic remains completely private—no public ingress or egress required (except for noted Schema Registry internal component access and provisioning requirements). Key Benefits of Confluent Cloud Private Link 1. Enhanced Security Your data stays fully within the cloud provider’s private network. This dramatically reduces exposure and eliminates the need for public-facing endpoints. Private Link provides defense-in-depth through isolated service-level connections, ensuring that network access is restricted to only the specific Confluent Cloud resources you’ve explicitly configured. 2. Simplified Networking with Important Caveats With Private Link, you can avoid: VPC/VNet peering and associated CIDR coordination complexity VPNs with their associated latency and complexity NAT gateways and associated costs Traditional firewall reconfiguration for IP whitelisting Infrastructure becomes cleaner, easier to manage, and more scalable. However, simplified networking does require DNS configuration: Organizations must: Create private hosted zones in their DNS service (Route 53 for AWS, equivalent for Azure/GCP) Create CNAME records mapping Confluent domains to their VPC endpoints Ensure DNS requests to public authorities can traverse to private DNS zones While simpler than VPC peering, Private Link DNS configuration does have operational complexity that security and networking teams should account for. 3. Internet Connectivity Requirements Organizations implementing fully private networking with Private Link must understand that VPCs using Private Link still require outbound internet access for: Confluent Cloud Schema Registry access (particularly for internal component connectivity) ksqlDB provisioning and management Confluent CLI authentication DNS requests to public authorities (particularly important for private hosted zone delegation) Management and control plane operation This is a critical consideration for firewall rules and egress filtering policies. 4. Performance Improvements Direct connectivity through Private Link often results in lower latency and higher throughput compared to public endpoints or complex routing architectures. This translates to improved application performance and better data pipeline efficiency, particularly important for real-time streaming