Proposed Draft: CI/CD Process for Scalable, Multi-Tenant Application

Overview

This document outlines a high-level Continuous Integration/Continuous Deployment (CI/CD) process for a scalable, multi-tenant application. The process includes considerations for operational health monitoring, blue/green deployments, and tenant isolation. This ensures that code changes are tested thoroughly, deployed reliably, and monitored effectively while maintaining data security, application performance and scalability, and operational stability.

Considerations Given

• Solution must be scalable and meet the needs of an enterprise product.
• Operational health monitoring should be included.
• Deployments should use blue/green strategy to minimize downtime and mitigate risks.
• The application is multi-tenant and this process should include tenant isolation for security and performance.

Process Steps

(See diagram below for a visual guide to these steps)

Source Code Management

Developers commit code to a version control system like Git. Branching strategy and/or tags can be used to isolate versions of software to build and deploy from.

Continuous Integration (CI)

• Code push automatically triggers CI pipeline.
• CI pipeline runs automated tests (unit, integration, and possibly end-to-end).
• Code quality checks (linting, code formatting) should be performed here.
• If all checks pass, artifacts are packaged and stored.

Continuous Deployment (CD)

• Upon successful CI pipeline, the CD pipeline is triggered.
• Suggest using Kubernetes or similar for deployment orchestration.
• Infrastructure as Code (IaC) provisions necessary resources (containers, VMs, etc.).

Blue/Green Deployment Strategy

• Application is deployed to staging environment first.
• If health checks pass, developers test in staging to verify.
• Developers approve staging environment if tests pass.
• A portion of traffic is routed to green for testing.
• Manual testing and verification happens here to ensure the green environment is up and running and ready for full traffic.
• On successful testing, all traffic is routed to green.
• On a failure, all traffic is routed back to blue and green is rolled back.
• Once the green environment is all deployed and finished, blue may either be updated to match green and used for a backup environment, or it can be destroyed and recreated next deployment.
• Traffic routing ensures a seamless transition between blue and green environments, removing the need for server warmup time, etc.
• Rollback mechanism is in place in case of deployment or application failures.

Software Versions and Tenants

• An assumption is made that all tenants are running the same version of the application.
• If different clients require different versions, additional structure would need to be created around git branches/tags, environment configuration, tenant configuration, deployment configuration, feature toggles, etc.

Operational Health Monitoring

• Implement monitoring tools (e.g., Prometheus, Grafana) to track performance, resource utilization, and application health.
• Set up alerts and notifications for critical thresholds.
• Log aggregation and analysis (e.g., ELK stack) for troubleshooting and debugging.

Tenant Isolation

• Application architecture is ideally structured around multi-tenancy. (e.g., Use a microservices architecture so that each service can be deployed and scoped to a single tenant or a group of tenants if needed.)
• Utilize containerization and Kubernetes namespaces for resource isolation.
• Implement Role-Based Access Control (RBAC) and other Kubernetes configurations for further isolation.

Continuous Feedback

• Collect feedback from monitoring systems, user reports, and customer support.
• Use feedback to iterate and improve the application.

Process Diagram

This diagram outlines the strategy outlined above in a sequence diagram.