Blue-green deployment in Microservices - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Blue-Green Deployment Basics

In a blue-green deployment setup, what is the primary purpose of having two identical environments named 'blue' and 'green'?

A To run two different versions of the application simultaneously for load balancing

B To allow switching traffic between two identical environments for zero downtime during deployment

C To test new features in the blue environment while the green environment is offline

D To have one environment for development and one for production

💡 Hint

Think about how deployments can avoid downtime by switching traffic.

Blue-green deployment uses two identical environments so that traffic can be switched from the old version (blue) to the new version (green) instantly, ensuring zero downtime.

❓ Architecture

intermediate

Traffic Routing in Blue-Green Deployment

Which component is most critical for directing user requests between the blue and green environments in a blue-green deployment?

A Load balancer or reverse proxy

B Database replication service

C Continuous integration server

D Application logging system

💡 Hint

Consider what directs user requests to different servers.

The load balancer or reverse proxy directs user traffic to either the blue or green environment, enabling smooth switching during deployment.

❓ scaling

advanced

Scaling Challenges in Blue-Green Deployment

When scaling a microservices application using blue-green deployment, which challenge is most likely to occur?

A Load balancer failing to distribute traffic evenly across multiple instances

B Increased database write conflicts due to simultaneous writes in both environments

C Difficulty in synchronizing session state between blue and green environments

D Inability to rollback to the previous version after deployment

💡 Hint

Think about user sessions and state when switching environments.

Synchronizing session state is challenging because users might be routed to different environments, which may not share session data, causing inconsistent user experience.

❓ tradeoff

advanced

Tradeoffs of Blue-Green Deployment

What is a significant tradeoff when using blue-green deployment compared to rolling updates?

A Blue-green deployment requires double the infrastructure cost during deployment

B Blue-green deployment increases deployment time significantly

C Blue-green deployment cannot support zero downtime deployments

D Blue-green deployment makes it impossible to rollback to previous versions

💡 Hint

Consider resource usage when maintaining two environments.

Blue-green deployment requires running two full environments simultaneously, which doubles infrastructure costs temporarily during deployment.

❓ estimation

expert

Capacity Estimation for Blue-Green Deployment

You manage a microservices system with a peak load of 10,000 requests per second. Using blue-green deployment, what is the minimum infrastructure capacity you should provision to ensure smooth deployment without performance degradation?

A Capacity for 15,000 requests per second, assuming 50% traffic shift during deployment

B Capacity for 5,000 requests per second, because traffic is split evenly between environments

C Capacity for 10,000 requests per second, since only one environment handles traffic at a time

D Capacity for 20,000 requests per second, to handle both blue and green environments simultaneously

💡 Hint

Both environments must be fully provisioned to handle the peak load during deployment.

Although only one environment handles live traffic at a time, blue-green deployment requires provisioning both environments simultaneously, each capable of handling the peak load of 10,000 RPS, for a total capacity of 20,000 RPS.