Software delivery and deployment have evolved over the years from manual processes to automated processes. During the days of the manual delivery process, once the deployment to the production server is ready, a major update is done during the night or when no users are accessing the server and there would be long server downtime but using the agile continuous delivery method, small iterations of changes are added seamlessly with the automated delivery process. In this article, let us discuss the continuous delivery process in Agile.
What is Continuous Delivery (CD) in Agile?
Continuous Delivery (CD) in Agile methodology is a software delivery process of short iterations and releasing new functionality once, it is ready for release.
- This involves the seamless and automated delivery of software in a small and incremental way.
- The primary goal of continuous delivery is to enable frequent release of software into production rapidly and predictably aligned with the principles of agile methodologies.
Key Concepts and Principles of Continuous Delivery in Agile
- Sprint-based releases: In agile scrum, every sprint becomes a potential release candidate enabled by the continuous delivery process. This leads to smaller and more frequent deployments for successful releases.
- Automation of all processes: Automating the build, testing, delivery, and deployment processes is the most important step in implementing continuous delivery in Agile.
- Build Quality: The quality of process and delivery is an integrated part of every continuous delivery in agile. All new piece of delivery is passed through automated tests to ensure everything is bug-free and meets the performance metrics for the highest quality.
- Reduced Risk: The automated testing and build process helps to avoid any bugs reaching production. This leads to quality delivery, improved software stability, and higher user satisfaction.
- Faster Feedback: Continuous delivery helps software features be added to production frequently and at a faster pace, which helps to receive quick user feedback, allowing the scrum team to adapt and iterate quickly.
- Improved Team Focus: Continuous delivery enables developers to focus on development and providing solutions, while it handles the deployment and delivery.
Key Steps in the Continuous Delivery Agile
- Code Development: While implementing the continuous delivery process in Agile for software development, the developers work on small and manageable pieces of functionality like user stories and write software code to add these features.
- Continuous Integration: Continuous integration occurs before the continuous delivery, when developers integrate their code changes to a version control repository like GIT.
- Artifact Generation: When successful integration and testing are done, the continuous integration process generates the artifacts such as compiled binaries or deployable packages for deployment to the server.
- Deployment Automation: Once the artifacts are generated the automated deployment takes these and deploys to the target server environment across different stages.
- Release to Production: In the continuous delivery process, once the automated tests in staging environment pass for the changes completed, the software changes are released to the production environment using different deployment methods to avoid any downtime.
- Monitoring and Feedback: After deployment is completed in production for particular release, continuous monitoring is done to gather any issue logs and other metrics to gather feedback on the performance and behavior of the application.
- Continuous Improvement: The continuous delivery in agile emphasizes continuous improvement and delivering value to customers continuously and in a more effective way.
Tools and Practices for Successful Continuous Delivery
Tools
- Version Control: GIT, SVN, Bitbucket, GitLab, GitHub and Mercurial are some of the version control tools that aids in the continuous delivery process. The version control tools help to track code changes, manage versions and collaborate with team for all code updates.
- CI/CD Tools: Jenkins, GitLab CI/CD, Azure DevOps and CircleCI are some of the best CI/CD tools, which help to navigate development delivery.
- Testing Tools: Selenium, Jira, Bugzilla, JMeter and LoadRunner are some of the testing and bug tracking tools.
Other Tools
- Ansible: It is used for configuration management, software deployment and task automation.
- Chef and Puppet: They are configuration management tools used for automation of infrastructure management.
Best Practices
- Automate everything: Automation of continuous delivery process is the key to reducing human errors, saving time, and ensuring consistency of continuous delivery.
- Use Version Control: Using the version control helps to track and manage changes to code base and roll back to previous versions, if situations arise. So version control tools should be used for code, scripts, configurations and documentation.
- Implement Testing strategy: Testing of the code is very essential to ensure quality and reliability before delivery. Testing strategy should be implemented to cover different types of tests like Unit test, Integration Test, Functional and Performance Tests. Testing tools should be used to run tests frequently
- Infrastructure as Code (IaC): Implement the IaC to define and manage infrastructure using code for consistent and continuous deployment.
- Monitoring and Feedback: To make the Continuous Delivery successful, continuous monitoring of the deployed applications and gathering feedback from users is very crucial.
- Adopt a Culture of Collaboration: For successful continuous delivery, fostering a culture of collaboration and continuous improvement is the key within the team members, stakeholders, and users.
Challenges and Considerations in Continuous Delivery
1. Tool Integration
- Using various tools for code build, testing and deployment can be complex and need lot of effort from DevOps team.
- Using the right tools and processes with significant effort for successful integration makes the CD process a success.
2. Security Risks
- Security can be an issue throughout the CD process which could derail the complete process.
- Security shouldbe a top priority by implementing the security measures like access control, vulnerability scanning and incident response plans.
3. Testing Bottlenecks
- Continuous and in-depth testing is crucial for continuous delivery but these can also slow down the process significantly.
- The CD process should ensure efficient and comprehensive testing using the right test automation tools.
4. Resistance to Change
- There can be stiff resistance to changes in implementing the CD process.
- Educating the team members and helping them understand the benefits of implementing the Agile CD process will help to overcome the resistance.
5. Communication and Collaboration
- There could be misunderstandings between teams which can hinder the process.
- An effective communication and collaboration between teams are essential for a successful CD implementation.
6. Frequent Code Changes
- Developers can be put at considerable pain due to frequent changes and due to that making code changes frequently.
- Avoid changes frequently without valid reason and help developers plan well in advance to handle changes when necessary.
Case Studies
1. BH-EHR Application
Challenge:
When the BH-EHR application was initially developed, it followed the manual process and waterfall method with large code delivery. This leads to longer wait times for customers before they can view the product progress. Also, the deployment process was very time-consuming and after every change, the complete code had to be built and deployed for the server. This causes lot of time to be taken and delays to occur frequently occurring.
Solution:
The development of the BH-EHR application was moved to implement the continuous delivery process using agile. This helped to cut down wait time for the customers to view each change and new features. The build and deployment process became easy with automated tools and testing tools made the code reliable and consistent using tools like GIT, Sourcetree and Bitbucket. There was no server downtime for deployment and frequent delivery was very smooth and effortless process with CD tools.
Result:
Continuous Delivery helped to cut down on time to market and deliver new features frequently which added value to business and customers.
2. Spotify
Challenge:
There is always demand for new features and issues being report regularly for bug fixes as millions of users globally use it and need a way to add new features and integrate bug fixes with minimal downtime and disruption.
Solution:
Spotify implemented a fully automated CI/CD pipeline with frequent deployments (multiple times per day) by using tools like Git, Jenkins, Hystrix (fault tolerance) and Canary Releases (gradual rollout).
Result:
Implementation of CD process lead to reduced time to market, improved application stability and increased user satisfaction.
Benefits of Continuous Delivery in Agile
- Faster time to market: Continuous delivery in agile helps in incremental releases to get features to users quickly in line with customer needs and market competitiveness.
- Increased Agility and Flexibility: The continuous delivery process helps in the ability to respond quickly to any requirement changes or market conditions. Smaller and frequent releases help to avoid longer wait time for integrating any new features and improvements.
- Improved Software Quality: Frequent testing and monitoring of delivered features with continuous delivery helps in a more stable and reliable software.
- Business Value: Continuous delivery leads to improved velocity, business value and higher productivity delivering value to customers.
- Consistent and Repeatable Process: Continuous delivery process relies in automated and standardized process to ensure consistency across cross functional teams which helps to maintain a reliable and repeatable release pipeline.
- Enhanced Collaboration: Faster and continuous feedback from continuous delivery helps in closer collaboration between all team members including developers, QA Team and all stakeholders.
Conclusion
Agile methodologies advocate a culture of efficiency, responsiveness, collaboration and responding to change quickly. With the continuous delivery process implementation, these agile principles are aligned well with the iterative and customer-centric development and delivery process. This helps to make the release process highly predictable, reliable and sustainable.