Tiers

In software deployment, an environment, or tier, is a computer system or set of systems in which a computer program or software component is deployed and executed.

Development System

Refers to the environment where software developers write, test, and initially run the new code. It's the initial stage in the software lifecycle and is isolated from the production environment to ensure that ongoing development does not impact end-users or the live application. This structured progression ensures that potential issues are identified and rectified in controlled environments before reaching the final users.

• Isolated Environment It provides an isolated space for individual developers or development teams to work without affecting others. Each developer may have a local development environment set up on their machine.

• Continuous Integration Support Development systems often include continuous integration pipelines that automatically build and test code as it is committed, enabling early detection of problems.

• Flexibility The development environment can be tailored to the specific needs of the developers, including preferred languages, frameworks, and libraries.

• Security Considerations While not as stringent as staging or production environments, there may still be specific security measures to protect code and intellectual property.

• Alignment with Production While maintaining its uniqueness, the development system should mirror the production environment as closely as practical, to minimize inconsistencies.

• Testing Support Developers can conduct unit testing and other low-level tests without interfering with the broader testing processes in staging or production environments..

Staging System

(often just referred to as "staging") is an environment that closely mirrors the production system, allowing teams to simulate how changes will behave before they are released to the actual live environment.

• Replica of Production The staging environment is set up to closely replicate the conditions of the production system, ensuring any tests accurately represent real-world scenarios.

• Acceptance Testing Before changes are deployed to production, they are released to the staging system to undergo various tests, identifying any potential issues.

• Safe Environment Staging provides a safe space where clients (Product Owner) can evaluate changes without the risk of affecting the end-users or the live data.

• Performance Analysis It allows teams to analyze the performance implications of their changes, ensuring that new releases won't degrade the user experience.

Production System

Refers to the environment where software applications or systems are deployed, operated, and made available to end-users for actual use. It contrasts with other environments like development, testing, or staging. In the DevOps lifecycle, once code has been developed, tested, and approved through various stages, it's deployed to the production system, making it live.

Any changes or failures in the production system are critical since they directly affect the end-users, hence the emphasis on robust deployment and monitoring practices in DevOps to maintain the integrity and reliability of the production system.

• Stability and Reliability Given that end-users interact directly with the production system, ensuring its uptime and stability is paramount.

• Monitoring and Alerting Implementing monitoring tools to track the system's health and performance, and setting up alerts for any anomalies.