Blue Green Deployment - Definition & Overview

What is Blue/Green Deployment?

Blue/green deployment is a software deployment approach that allows organizations to release new code with minimal downtime and easy rollbacks. In this strategy, two identical environments are set up: one actively handles user requests while the other remains idle, ready to take over when needed. New updates are initially deployed to the active environment, where they are thoroughly tested for bugs. If errors are detected, the idle environment provides a fallback option, enabling traffic to be instantly redirected to it and ensuring uninterrupted service.

How Does a Blue-Green Deployment Work?

Blue-Green deployment employs a parallel deployment principle, utilizing two identical environments simultaneously. This involves duplicating every component, including the application server, user interface, database system and all other software infrastructure elements.

Two servers are maintained in this setup, with only one being live and fully operational at any given time. The active blue server is responsible for handling public traffic from the domain name system and serves as the production server, while the inactive green server remains in standby mode, acting as the staging server and ready to assume responsibility when necessary.

To better understand the blue-green deployment process, let's explore the key stages involved in its execution.

Stage 1 – Resource Duplication

While deploying two identical environments, a shared database is used to make updates smoother, reducing complexity and maintaining consistency.

Stage 2 - Server Update Process

The dormant server is upgraded with the latest features of the web application. These changes are thoroughly tested on the inactive server to validate functionality before going live, ensuring reliability while minimizing the risk of downtime and enhancing user experience.

Stage 3 – Redirecting Traffic to the Updated Server

Traffic redirection moves users from the old server to the newly updated one. This requires a routing device, such as a load balancer, to direct traffic under the same domain name. The seamless transition ensures continuous service availability for users.

Stage 4 - Backup Configuration and Deployment Cycle

The original active server transitions to become the inactive backup server. This server then serves as both a recovery option and a staging area for the next update. The cycle continues with each deployment, enabling a consistent and reliable system.

Why is it Important?

Blue/green deployment is vital for organizations needing continuous service, as it supports efficient updates and minimizes service interruptions. This approach also facilitates comprehensive testing in a live environment, ensuring new features function as intended before full release. Moreover, it improves customer experience by providing immediate access to updates, supporting CI/CD practices and maintaining operational efficiency with a built-in disaster recovery mechanism.

Advantages of Blue/Green Deployments

Blue/green deployments provide a strategic method for reducing downtime and mitigating risks during updates. By using two parallel environments, teams can test new features in real-time without affecting users, ensuring a smooth user experience and greater system dependability.

Here are the key advantages:

1. Automatic and Smooth Upgrades

Blue-green deployment automates server switching and traffic management, delivering a user-friendly experience. By gradually routing traffic with a load balancer, it prevents abrupt disconnections for users. Programmable load balancers also simplify the developers' workload, even if the full transfer requires additional time.

2. Testing in Live Environments

Testing in production lets the team evaluate product functionality once it is live on a server, offering insights from the user's perspective. This proactive testing minimizes the chance of unexpected issues during deployment, as potential glitches are identified and resolved without impacting end users.

3. Business Continuity with Standby Servers

Blue-green deployment provides a resilient system with a standby server to handle failures. This setup minimizes risks, and ensures uninterrupted service, even during challenges like malware attacks. If the live server encounters a problem, traffic is redirected instantly to the standby server to continue business operations.

4. Effortless Rollbacks

Blue/green deployments simplify rollbacks by allowing teams to quickly revert to a stable version if issues arise, safeguarding live environments. Routing adjustments enable a swift return to a reliable state, and for stateful applications, read-only modes or load balancers can be used to complete all transactions before switching.

5. Rapid Software Releases

In a CI/CD environment, blue/green deployments support rapid software releases. DevOps teams can deploy updates smoothly without delays, reducing error rates and stress by allowing ample time for the update process. This approach keeps software up-to-date while maintaining stability.

Real-Life Use Cases

Discover real-world scenarios where blue/green deployments improve uptime, streamline updates, and ensure seamless rollbacks.

Netflix

By using blue/green deployment, Netflix enhances viewer satisfaction through uninterrupted streaming, even during updates. This approach enables Netflix to confidently introduce new features without risking downtime, ensuring a stable and reliable experience for users. If any issues arise, Netflix can seamlessly switch back, maintaining consistent service quality and reinforcing its reputation for reliability.

Google

Google’s use of blue/green deployment on Google Cloud Platform (GCP) allows it to provide continuous, reliable service with minimal disruptions. This strategy enables Google to introduce updates confidently, thoroughly testing them in a separate environment before switching user traffic. By maintaining an instant fallback option, Google reduces risks and delivers a smooth, high-quality experience, reinforcing user trust and service stability.