Application traffic splitting in Google Cloud Platform is a powerful feature primarily used with App Engine that allows you to distribute incoming requests across multiple versions of your application. This capability is essential for performing gradual rollouts, A/B testing, and canary deployments…Application traffic splitting in Google Cloud Platform is a powerful feature primarily used with App Engine that allows you to distribute incoming requests across multiple versions of your application. This capability is essential for performing gradual rollouts, A/B testing, and canary deployments.
To adjust traffic splitting, you can use the Google Cloud Console, gcloud CLI, or the Admin API. In the Console, navigate to App Engine > Versions, select the versions you want to include, and click 'Split Traffic.' You can then specify the percentage of traffic each version should receive.
Using gcloud CLI, the command is: gcloud app services set-traffic [SERVICE] --splits [VERSION1]=[WEIGHT1],[VERSION2]=[WEIGHT2]
For example: gcloud app services set-traffic default --splits v1=0.5,v2=0.5 would send 50% of traffic to each version.
Three splitting methods are available:
1. IP Address Splitting: Routes users based on their IP address hash. This ensures users consistently reach the same version but may be less accurate behind proxies.
2. Cookie Splitting: Uses the GOOGAPPUID cookie to maintain user-version affinity. This provides more accurate splitting and is recommended for applications requiring session consistency.
3. Random Splitting: Distributes requests randomly based on specified weights. This is useful when session affinity is not required.
To specify the splitting method via CLI, use the --split-by flag with values: ip, cookie, or random.
Best practices include starting with small traffic percentages to new versions, monitoring error rates and latency during transitions, and having rollback plans ready. You should also ensure your application handles traffic from multiple versions gracefully, particularly regarding database schemas and API compatibility.
Traffic splitting enables zero-downtime deployments and reduces risk when releasing new features to production environments.
Traffic splitting is a critical capability for modern cloud applications that allows you to distribute incoming requests across multiple versions of your application. This is essential for:
• Canary deployments - Testing new versions with a small percentage of users before full rollout • A/B testing - Comparing different application versions to measure performance or user engagement • Gradual migrations - Slowly shifting traffic from legacy to new versions to minimize risk • Blue-green deployments - Enabling quick rollbacks if issues are detected
What is Traffic Splitting?
Traffic splitting in Google Cloud Platform refers to the ability to route percentages of incoming traffic to different versions of your application. This feature is primarily available in:
• Google App Engine - Native traffic splitting between application versions • Cloud Run - Traffic management between revisions • Google Kubernetes Engine (GKE) - Using Istio or Gateway API for traffic management
How Traffic Splitting Works
In App Engine: You can split traffic using three methods: • IP address splitting - Routes users to versions based on their IP address hash • Cookie splitting - Uses GOOGAPPUID cookie for consistent user experience • Random splitting - Distributes traffic randomly based on configured percentages
For example: gcloud app services set-traffic default --splits v1=0.7,v2=0.3 This sends 70% of traffic to v1 and 30% to v2.
In Cloud Run: Traffic can be split between revisions using: • Console - Adjust percentages in the Revisions tab • gcloud - Use gcloud run services update-traffic command • YAML configuration - Define traffic splits in service specifications
Key Commands to Remember
• gcloud app services set-traffic - Set traffic allocation for App Engine • gcloud app services describe - View current traffic allocation • gcloud run services update-traffic - Modify Cloud Run traffic splits • --migrate flag - Gradually migrate traffic to a new version • --split-by flag - Specify splitting method (ip, cookie, or random)
Exam Tips: Answering Questions on Adjusting Application Traffic Splitting
Key Concepts to Master:
1. Know the splitting methods - Understand when to use IP-based vs cookie-based vs random splitting. Cookie-based ensures users consistently see the same version.
2. Understand percentage allocation - Traffic percentages must total 100%. Be prepared to calculate splits for scenarios.
3. Remember the commands - Focus on gcloud commands for both App Engine and Cloud Run traffic management.
4. Recognize use cases - Questions often present scenarios where you must identify if traffic splitting is the appropriate solution.
5. Migration scenarios - The --migrate flag enables gradual traffic shifting, which is useful for zero-downtime deployments.
Common Exam Scenarios:
• Rolling out a new feature to 10% of users - Use traffic splitting with 90/10 ratio • Ensuring users see consistent versions - Choose cookie-based splitting • Quick rollback needed - Shift traffic back to previous version using set-traffic command • Testing performance of new code - Implement canary deployment with small traffic percentage
Watch Out For:
• Questions that confuse traffic splitting with load balancing - they serve different purposes • Scenarios requiring sticky sessions - cookie-based splitting is the answer • Version naming conventions in commands • Understanding that traffic splitting happens at the service level, not project level