An SRE team manages a mission-critical, multi-region application deployed across Google Cloud. During sudden traffic surges, horizontal autoscaling operations intermittently fail when Compute Engine regional CPU allocation quotas are depleted, resulting in ResourceExhausted (HTTP 429 / gRPC 8) errors and degraded service availability. The team requires an automated, proactive capacity management solution that meets these requirements: Continuously calculates allocation quota utilization percentages across regions in real time before resource requests are rejected. Triggers an alert when allocation quota usage exceeds 85% of the configured regional limit. Automatically invokes an automated remediation pipeline to adjust quotas programmatically or reroute traffic before total exhaustion occurs. Which solution should the team implement?

Configure a Cloud Monitoring alerting policy using Metric Query Language (MQL) that joins `serviceruntime.googleapis.com/quota/allocation/usage` and `serviceruntime.googleapis.com/quota/limit`, calculates the utilization ratio using `div`, alerts when utilization exceeds 0.85, and routes notifications to Pub/Sub to trigger an automated remediation Cloud Function.: What this solution is This solution implements proactive quota monitoring and automated capacity mitigation by combining Cloud Monitoring Metric Query Language (MQL) with Google Cloud Pub/Sub and automated serverless workflows. MQL provides advanced querying capabilities that allow multiple time series—such as dynamic usage and dynamic quota limits—to be combined and evaluated mathematically. How it meets the requirements Calculates quota utilization percentage in real time: Quota limits and quota usage are stored as separate metrics in Cloud Monitoring under the consumer_quota resource. MQL fetches both serviceruntime.googleapis.com/quota/allocation/usage and serviceruntime.googleapis.com/quota/limit, aligns them across identical resource dimensions (such as quota_metric, region, and project_id), joins the streams, and uses the div operator to compute the exact utilization ratio in real time. Alerts at 85% threshold: The MQL condition condition val() > 0.85 triggers an incident as soon as consumption reaches 85% of the current limit, well before total exhaustion. Automated remediation before exhaustion: By configuring the Cloud Monitoring alerting policy to send notifications to a Cloud Pub/Sub topic, a subscriber (such as a Cloud Function or Cloud Run service) can immediately execute remediation tasks. This includes submitting an automated quota increase request via the Cloud Quotas API or dynamically adjusting regional traffic weights in the Cloud Load Balancer. Key advantages Proactive rather than reactive: Catches capacity saturation before any ResourceExhausted errors affect production traffic. Dynamic limit tracking: Automatically adapts when quotas are modified, avoiding brittle static threshold definitions. Decoupled remediation: Enables custom programmatic remediation pipelines through standard Pub/Sub event-driven architectures. Why this is optimal Monitoring quota utilization as a calculated ratio (usage / limit) is the recommended Site Reliability Engineering practice in Google Cloud. It provides complete observability into capacity constraints without requiring static threshold updates when regional limits are adjusted.