What Is Deployment?
Deployment refers to the process of making a software system or application available for use. It encompasses activities such as packaging, building, releasing, installing, and activating the software.
Uses of Deployments
Deployments are essential for distributing new applications, services, or updates to users. This often involves halting the current application and restarting the server to implement changes. Debugging compiles the source code into an executable file, which is then deployed to the environment. The server restarts to verify functionality. If no issues arise, the deployment is considered successful.
Principles of Deployments
Deployment strategies vary, including blue/green, immutable, symbolic, and rolling deployments, each with unique approaches to updating environments while minimizing downtime and risk.
1. Blue/Green Deployment
Blue/green deployment involves maintaining two environments: the ‘blue’ current production and the ‘green’ next-stage environment. Once the ‘green’ is ready, it swaps roles with ‘blue,’ facilitating immediate updates with minimal downtime.
2. Immutable Deployment
Immutable deployment discards the original environment after successfully switching to the new one. It prevents the accumulation of changes over time, ensuring consistency and reliability.
3. Symbolic Deployment
Symbolic deployment uses symbolic links to switch between the current and new program versions, maintaining a single server environment and enabling quick rollbacks if necessary.
4. Rolling Deployment
Rolling deployment updates servers sequentially, reducing downtime but increasing complexity in managing different environment versions during the deployment.
How to Choose Deployments
The choice of deployment strategy depends on the specific needs, risk tolerance, and infrastructure of the project.
1. Blue/Green Deployment
Best for scenarios requiring high availability and minimal downtime. Although it ensures easy rollback and continuous operation, it incurs higher costs due to dual environment maintenance.
2. Immutable Deployment
Suitable for projects prioritizing environment consistency and lower maintenance costs, as it avoids leaving outdated servers running.
3. Symbolic Deployment
Ideal for smaller-scale deployments where server resources are limited. However, it carries the risk of downtime if issues arise during the switch.
4. Rolling Deployment
Favors fast deployment cycles but comes with complexities in managing transitional states between old and new versions, complicating rollbacks.