A healthcare provider relies on a mission-critical patient record processing backend running on Compute Engine regional Managed Instance Groups (MIGs) behind a Global External Application Load Balancer. The engineering team is preparing to execute a blue-green deployment strategy for a major release that includes database structure updates. Which TWO technical steps must be executed to ensure zero downtime and prevent deployment failure?
- Implement an expand-contract database schema migration pattern to ensure the database layer maintains backwards compatibility with both blue and green application instances concurrently.Cevap
- Assess regional compute quotas in the target deployment region ahead of time and request quota increases to accommodate running duplicate MIG capacity during the release window.Cevap
- CApply destructive database schema modifications directly to the database immediately prior to updating load balancer backend service target groups.
- DMigrate the entire application workload from Compute Engine MIGs to a dedicated GKE cluster solely to execute HTTP traffic shifting.
Cevap
The engineering team must implement an expand-contract database schema migration pattern to ensure schema compatibility across versions, and assess and request regional compute quota increases prior to deployment to support running concurrent blue and green environments.
Blue-green releases require two key safeguards when handling stateful or database-backed applications: first, database schema changes must be backward-compatible (expand-contract method) so both application revisions run cleanly against the shared database. Second, because blue and green MIGs run simultaneously at 100% capacity during validation, regional resource quotas must be checked and increased prior to initiating the deployment.
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Anahtar Kavram
Executing zero-downtime blue-green deployments requires database schema backward compatibility and pre-provisioned regional infrastructure quotas for concurrent environments.