Integration patterns with external systems

Implement Secure Identity and Access Frameworks

Secure External Integration and Authentication

Integrating Google Cloud with external systems often relies on the handover pattern to safely pass data across environments. Under this pattern, workloads in a private data center or another cloud upload data to shared storage, such as Cloud Storage or Pub/Sub, where Google Cloud services can then process it. The physical path for this data relies on either Cloud Interconnect or a VPN, depending on your traffic volume and security needs. To make this connection secure, Workload Identity Federation is the preferred service for authenticating external systems. This service allows workloads from external environments like AWS, Azure, or GitHub to access cloud resources using short-lived credentials, such as OAuth 2.0 tokens, which eliminates the security risk of managing long-lived service account keys.

Access Management and Security Perimeters

Once identities are authenticated, administrators must enforce the principle of least privilege using Identity and Access Management (IAM). For application-to-application security, a Service Account acts as the primary identity for each workload. Instead of managing permissions for individual users, administrators can use Google Groups to perform bulk access updates. To protect sensitive data as it moves between these environments, VPC Service Controls establish a security perimeter around cloud resources. This security framework prevents data exfiltration by restricting service access to authorized networks, and you can extend this boundary to hybrid environments through a secure network connection.

When organizing access, administrators manage identities using three primary categories:

• Corporate Identities: Managed through Cloud Identity or Google Workspace for employee access.
• Workload Identities: Used by applications to interact with other cloud services securely.
• Customer Identities: Managed via Identity Platform for external users of your applications.

High Availability and Reliability

To maintain continuous operations during an infrastructure outage, architectures should distribute resources across multiple zones or regions. For network paths, HA VPN provides a highly resilient connection by using two interfaces to guarantee traffic flow even if one zone fails. Additionally, Cloud Load Balancing routes incoming traffic only to healthy instances across your deployment. Preparing for these potential failures ensures that external integrations remain highly responsive and meet your business availability goals.

Analyze Hybrid and Multi-Cloud Network Connectivity

Virtual Private Networks and Physical Connections

Connecting Google Cloud to on-premises data centers or other cloud providers requires evaluating bandwidth, latency, and reliability. For low-volume data transfers, Cloud VPN provides a simple way to connect networks over the public internet using an IPsec VPN tunnel. To achieve higher reliability over the internet, HA VPN uses multiple tunnels to offer a 99.99% service level agreement, though it remains subject to public internet performance. When a workload requires deterministic performance and bypasses the public internet entirely, Cloud Interconnect provides a private, physical link.

Architects can choose between two main types of physical interconnects based on their location and requirements:

• Dedicated Interconnect: A direct physical link between your network and Google’s network for very high-bandwidth needs.
• Partner Interconnect: A connection provided through a service provider for organizations that cannot physically reach a Google colocation facility.

Multi-Cloud and Private Service Connectivity

For companies operating across multiple cloud platforms, Cross-Cloud Interconnect is a managed service that directly links Google Cloud with other providers like AWS or Azure. This service establishes high-bandwidth dedicated connectivity without requiring your team to manage physical hardware in remote colocation facilities, which reduces the total cost of ownership. When workloads need to access Google APIs or internal services privately, Private Service Connect uses internal IP addresses to keep sensitive traffic completely off the public internet. To ensure a strong security posture, you should always protect this private data in transit using encryption methods like MACsec or TLS. Finally, operators can monitor and troubleshoot these complex hybrid connections from a single console using the Network Intelligence Center.

Differentiate Synchronous and Asynchronous Integration Patterns

Synchronous Communication and API Management

Selecting the proper communication style is critical for maintaining application performance across boundaries. Synchronous integration is a real-time communication pattern where the sender must wait for a response from the receiver before proceeding. While this pattern is straightforward, it introduces tight dependencies that can slow down or break your application if an external service fails or responds slowly. To manage these dependencies, API-driven architectures use Apigee as an API management platform. Apigee acts as a facade that hides backend complexity, unifies security policies like OAuth 2.0, and shields client applications from changes made to the backend code.

Asynchronous Communication and Hybrid Performance

To avoid the tight dependencies of real-time calls, systems can use asynchronous messaging to exchange data without waiting for an immediate response. Pub/Sub is a messaging service designed to achieve decoupling, allowing different components of your architecture to function independently. This decoupling is essential for maintaining system reliability and absorbing traffic spikes or temporary network outages without failing. In hybrid setups, using Private Service Connect provides private connectivity to keep this data flow secure. Architects should generally avoid high dependencies on synchronous calls between environments to prevent performance bottlenecks.

Integration Design Tradeoffs

Choosing between communication patterns involves balancing immediate feedback against overall system resilience:

• Synchronous Patterns: Provide immediate, real-time data exchange but risk system-wide failures if any external dependency goes offline.
• Asynchronous Patterns: Enhance scalability and resilience by letting tasks process in the background, allowing the system to handle spikes smoothly.