What routing and failover policies protect workloads on Google Cloud from regional cable cuts?

To proactively spot latency spikes on Google Cloud before customers do, SREs should use a multi-layered approach, creating custom dashboards in Cloud Monitoring that combine platform-wide network intelligence with deep, service-specific metrics. Early warnings can come from either a degradation of the underlying network or from saturation in a specific application service.

• Layer 1: Network Intelligence Center

The Google Cloud Performance Dashboard provides a high-level view of network health. It's the first place to look for signs of a broader network issue, which can often precede application-level problems. 

• Layer 2: Application-layer observability

Custom dashboards in Cloud Monitoring should be configured to capture fine-grained metrics for your specific workloads. This provides early warnings of application-level saturation that can cause user-facing latency.

• Layer 3: Tracing and logging

For deeper analysis during an incident, integrate and analyze data from Cloud Trace and Cloud Logging.

Following recent incidents affecting cloud providers, including Google Cloud (GCP) networking issues, disaster recovery (DR) testing for critical GCP services must evolve to simulate complex, multi-layered failures. Testing should focus on validating cross-regional failover, application resilience during partial degradation, and hybrid cloud strategies, moving beyond simple single-zone outage scenarios.

• Validate cross-regional failover (Game Day)
• Verify application behavior during partial degradation
• Conduct multi-cloud or hybrid failover testing
• Practice communication and documentation

In light of recent, multi-regional connectivity disruptions, such as the July 2024 issue impacting Google Cloud Networking, runbooks for Google Cloud Platform (GCP) must shift from reactive, single-failure responses toward proactive detection and multi-layered, hybrid failover strategies. A passive approach assuming regional isolation is no longer sufficient.