CompTIA Cloud+ Practice Test

What type of deployment methodology uses two identical configurations to avoid downtime during maintenance?

1. Rolling

2. Blue-green

3. High-availability clustering

4. DevOps

The correct answer is: Blue-green

The blue-green deployment methodology utilizes two identical environments—referred to as "blue" and "green"—that are set up in such a way that one is active while the other is idle. This approach minimizes downtime during maintenance or deployment of new features. When a new version of the application is ready, it is deployed to the idle environment (green) while the current version (blue) continues to serve users. Once the new version is verified and tested in the idle environment, the traffic is switched from the blue environment to the green, making it the live environment. If any issues arise, it's simple to switch back to the blue environment, thus ensuring high availability and seamless transitions without impacting user experience. In contrast, the other methodologies mentioned do not specifically focus on maintaining zero downtime during maintenance in the same manner. Rolling deployments gradually introduce changes to a subset of servers, which can result in temporary unavailability during updates. High-availability clustering focuses on improving uptime through redundancy, but not specifically through dual configurations for easy switching. DevOps is a cultural and operational framework that enhances collaboration between development and operations, leading to faster and more reliable deployment processes, but it doesn't define a specific deployment methodology structured for zero downtime like blue-green does.