Today, i got refreshed on Blue Green Deployment from a podcast https://open.spotify.com/episode/03p86zgOuSEbNezK71CELH. Deployment designing is a plate i haven’t touched yet. In this blog i jot down the notes on blue green deployment for my future self.

What is Blue-Green Deployment?

Blue-Green Deployment is a release management strategy that involves maintaining two identical environments, referred to as “Blue” and “Green.” At any point in time, only one environment is live (receiving traffic), while the other remains idle or in standby. Updates are deployed to the idle environment, thoroughly tested, and then switched to live with minimal downtime.

How It Works

• This approach involves setting up two environments: the Blue environment, which serves live traffic, and the Green environment, a replica used for staging updates.
• Updates are first deployed to the Green environment, where comprehensive testing is performed to ensure functionality, performance, and integration meet expectations.
• Once testing is successful, the routing mechanism, such as a DNS or API Gateway or load balancer, is updated to redirect traffic from the Blue environment to the Green environment.
• The Green environment then becomes live, while the Blue environment transitions to an idle state.
• If issues arise, traffic can be reverted to the Blue environment for a quick recovery with minimal impact.

Benefits of Blue-Green Deployment

• Blue-Green Deployment provides zero downtime during the deployment process, ensuring uninterrupted user experiences.
• Rollbacks are simplified because the previous version remains intact in the Blue environment, enabling quick reversion if necessary. Consideration of forward and backwar capability is important. eg, Database.
• It also allows seamless testing in the Green environment before updates go live, reducing risks by isolating production from deployment issues.

Challenges and Considerations

• Maintaining two identical environments can be resource intensive.
• Ensuring synchronization between environments is critical to prevent discrepancies in configuration and data.
• Handling live database changes during the environment switch is complex, requiring careful planning for database migrations.

Implementing Blue-Green Deployment (Not Yet Tried)

• Several tools and platforms support Blue-Green Deployment. Kubernetes simplifies managing multiple environments through namespaces and services.
• AWS Elastic Beanstalk offers built-in support for Blue-Green Deployment, while HashiCorp Terraform automates the setup of Blue-Green infrastructure.
• To implement this strategy, organizations should design infrastructure capable of supporting two identical environments, automate deployments using CI/CD pipelines, monitor and test thoroughly, and define rollback procedures to revert to previous versions when necessary.

Reference:

• AWS – https://docs.aws.amazon.com/whitepapers/latest/overview-deployment-options/bluegreen-deployments.html