What is continuous deployment?
Definition: Continuous deployment is a software development practice of automating the building, testing, and deploying of new code changes.
The deployment process is automated, and the code is tested before its release to end users. New code changes are automatically built and deployed as soon as they are committed to the source code repository.
This allows developers to deliver software updates faster, without manual intervention, and without worrying about faulty code, as the new code is automatically tested and verified before deployment.
Continuous deployment is a key component of continuous delivery, requiring a solid foundation in continuous integration, testing, and delivery.
Continuous deployment vs. continuous delivery vs. continuous integration
Continuous Integration (CI) allows developers to write code on different machines merging their changes into one codebase that is automatically compiled and tested for errors. It helps the software run without stopping and developers to write code continuously.
Continuous Delivery (CD) is the continuation of CI and is the process of deploying code changes automatically to the testing and building environment. It automates the release process by keeping the software ready for deployment as soon as the new build is approved, but it still needs someone to push the official release.
Continuous Deployment (CDel) automatically releases every new code change that passes all tests without human intervention. It combines CI and CD, automating the process from code writing to releasing, letting the team focus on developing new features and customer feedback.
All three methods start at the same point, but the difference is where they stop, at the integration point, release, or encompass the whole process, like continuous deployment.
Continuous deployment tools
An automated system needs many tools to run efficiently, like:
- Version control is used to track changes to the codebase allowing teams to see new changes made to the project. It allows multiple developers to collaborate on the same project by merging all changes into one code repository.
- Code review uses various tools to test the new code and identify bugs or errors that need to be fixed. This improves the software quality and team efficiency by letting them spot issues before the code is passed to production.
- Continuous integration (CI) automates the process of building and testing code changes, improving efficiency by letting developers focus on writing code.
- Configuration management maintains a constant state of software and hardware components like servers, networks, databases, and storage to ensure the stability of the deployment environment and reduce downtime upon new code changes.
- Release automation automates all necessary steps until the production stage, connecting processes and ensuring developers follow all protocols before deploying code changes.
- Infrastructure monitoring is essential in an automated system of continuous deployment. It monitors the software state and infrastructure around it identifying any issues and warning the developers about them.
- Log management collects logs from every system involved in the development process and centralizes them, making tracking every new change to the software easier.
Every system will need different tools based on their needs. Still, these are the basis of a working continuous deployment system.
Continuous deployment best practices
Start manually - Before committing to building a CDel system, understand the manual release pipeline your team is using. Creating an automated system with a basis behind it will be easier.
Commit often - While writing code, make an effort to commit as soon as progress is made, even if it’s just a few lines of code. The system should test bit by bit rather than feature by feature.
Shorten test times - The idea behind CDel is the speed of deployment, and lengthy tests will slow the process down. Focus on the essential tests and use complex tests only when necessary.
Clean the environments - In between each deployment, the whole process should be cleaned for maximum efficiency for the next deployment round.
Monitor the pipeline - Set up systems for analyzing when warnings were issued to determine where the system needs more work or where the team is making the most mistakes.
Stop any manual deployment - Once the system is set up, there should be no more manual involvement to avoid any risk to the overall development system.
Example of continuous deployment
A developer is working on a new feature and just wrote 70 lines of new code.
He commits the code changes to a shared repository on GitHub.
The code changes trigger an automated build process that compiles it and runs tests to check for bugs.
If the system flags the code as faulty, the developer is notified to fix it.
If it passes all tests, the system deems the build successful and automatically deploys it to the production environment where the end-user can access it.
After submitting the code changes, the developer can start writing new code or fix the faulty one without waiting for the system to deploy it. The idea is to have seamless code changes.
