What is Continuous Delivery in Devops?
By Sourojit Das, Community Contributor - March 9, 2023
What is Continuous Delivery in DevOps
Continuous delivery (CD) is a software development methodology in which code modifications are automatically packaged and deployed to production. It aims to accelerate development, cut expenses, and lower risks without losing code quality.
CD is attained by designing a simple release procedure that is easily reproducible and restricts manual activities. In an ideal CD procedure, only application deployment into production requires human participation.
Once a development team has accomplished continuous integration, CD is the next step in software pipeline automation (CI). CI automates the merging and testing of code modifications, focusing particularly on unit testing. The application is deployed to a staging environment for additional testing once the code has passed evaluations. These assessments consist of integration testing, performance testing, user interface testing, and more.
CI and CD constitute the CI/CD pipeline, which transfers code from the computers of individual developers via automated testing to a production-ready build. At this point, all that is required is for a team member to deploy the latest version manually, often at regular intervals. With the emphasis on automation and velocity, CI/CD is a pillar of the DevOps concept.
Why is it important?
In a typical waterfall lifecycle, a customer release (minor or major) is a significant milestone that requires months of work. The entire crew is focused on achieving this objective. The release’s features are developed, tested, and merged into the main branch as a single unit. There is a huge cost associated with failed releases and intense pressure to achieve deadlines. Consumers also wait lengthy durations for resolutions to their problems. Significant downtime occurs when the release patch is applied.
Contrast this with the Agile model’s shorter release lifecycle. Here, features can be checked into the central repository every day (Continuous Integration). Automated suites of unit, regression, and system tests ensure that freshly contributed code is quickly validated. Effect on relevant characteristics is examined. If this code can then be deployed promptly to customers, the strain surrounding a customer release is eliminated. Releasing becomes a common, low-risk, and automated occurrence. Manual errors are eliminated from the releasing procedure. Even during holidays, urgent fixes and updates can be issued with minimum manpower. This led to the evolution of Continuous Delivery.
How to Build a Continuous Delivery Pipeline
Continuous delivery pipelines extend the operations and technologies currently implemented for a CI pipeline. Throughout the CI process, the code has been compiled to construct the application and unit-tested to ensure its functionality and quality. If the application fails to build or the unit tests fail, the code is returned to the developers to remediate and test again.
Now, the application is prepared for additional testing. You will need a method to generate a staging environment identical to the production setting. Development teams generally resort to cloud services to provide a multistage environment to host the application and organise the testing workflow, since cloud hosting can expand to match processing demands.
A CD pipeline may contain quality gates that establish success criteria. Before the program may advance to the subsequent phase, the performance, integration, and user interface (UI) tests must achieve these criteria. AI may be effective for identifying failure causes and viable solutions.
You should automate as many tests and processes as possible as part of this testing strategy. This reduces the risk of human mistakes associated with manual methods, such as executing tests in a different order, as well as enhances speed. Everything related to Continuous Delivery in DevOps should be uniform and repeatable.
Lastly, invest in observation and monitoring systems, as a failure in one segment of the pipeline could cause the entire system to fail. Including automated alarms and redundancies will ensure that, for instance, the failure of a single testing tool does not affect client delivery.
A Case Study of Continuous Delivery in DevOps
Without executing Acceptance Tests in a production-like environment, developers have no idea if the application fulfils the customer’s requirements or can be deployed and survive in the real world. They must expand the scope of their continuous integration process if they want quick input on these topics.
The developers thus took Continuous Integration (Continuous Delivery) to the next level by introducing a few simple, automated Acceptance Tests that demonstrated that the application operated and could perform its most basic job.
Essentially, they designed a Continuous Delivery pipeline to ensure that the application is deployed effortlessly on the production environment by ensuring that the program functions properly when installed on a replica of the production server.
Benefits of Continuous Delivery in DevOps
1. Quicker detection of defects
Continuous Delivery in DevOps is based on a robust testing technique, automatically testing an application against expected behaviour after deployment in the “real world.” This allows developers to uncover flaws before pushing the code to production, where they may cause user disruptions and irritation.
Not only does Continuous Delivery in DevOps boost user satisfaction, but it also enables the development team to anticipate these flaws in future releases, whereas a fault that does not actively disrupt the program may never be found and hence never be repaired.
2. Reduction of Costs
By removing manual processes, Continuous Delivery in DevOps reduces the cost of delivering new software and upgrades, allowing developers to spend more time on higher-order tasks. Also, the speed of a CI/CD pipeline allows for the quicker delivery of additional features. This boosts the development team’s output and frees up bandwidth to explore more projects without the need to hire additional engineers.
3. Improve quality.
Continuous Delivery in DevOps is used to standardise an application’s requirements by embodying them in test cases, hence increasing the likelihood that the result will meet users’ needs.
Continuous Delivery in DevOps also enables development teams to offer a minimally viable product (MVP) more quickly, allowing the customer to provide immediate feedback on improvement areas. Developers want feedback in order to continue offering consumer value.
Generally speaking, an agile approach is superior to a waterfall process in which the customer does not see the final product until its completion. All the effort spent designing the final product is now a sunk cost if the customer decides after delivery that it does not match their requirements.
4. Reduce Risk
The primary objective of every software deployment should be “do no harm.” The second objective is to provide value to the client, but they cannot appreciate an improved UI, for instance, if the program is unavailable due to the upgrade.
By standardising the release process and implementing test validations to discover defects before they are published into production, Continuous Delivery (CD) reduces the risk associated with each deployment and instils greater confidence in the application among developers.
5. Increase employee satisfaction.
It is hardly a secret that people prefer cognitive jobs to manual, repetitive ones. By establishing an automated CD workflow, a business removes pain points for its developers and frees them to focus on strategy and optimization. In addition, the speed of CD pipelines expedites the deployment of engineers’ code, allowing them to observe the impact of their work and how it assists customers in achieving their objectives.
6. Hasten Product Delivery
CD eliminates obstacles in the development process so that updates can be deployed as soon as they have been validated. Its efficiency enables the engineering team to put out new features quickly to meet consumer demands. When an important issue arises, this speed advantage pays greater returns since it enables developers to deploy security updates and other solutions quickly.
To Sum Up
After a team has mastered the CI pipeline, the next stage in automating the development process is continuous delivery (CD). Based on the demands of the client and the organisation, DevOps teams may progress beyond continuous delivery to continuous deployment and streamline the entire pipeline from code to customer. In this circumstance, continuous delivery is still an intermediate step toward the ultimate objective of automated deployments.
Continuous Delivery in DevOps is used to automate and standardise the testing process for applications to ensure their readiness to satisfy real-world user needs. In addition to numerous additional benefits for developers and their clients, this technique identifies errors faster, improves product quality, and reduces development costs.
However, all tests, including unit tests, need to be conducted on real devices for optimum results. Testing is only 100% effective when the tests are executed under real user conditions. Emulators/Simulators and Virtual Machines cannot fully replicate the specific conditions under which devices operate and thus, their results do not inspire sufficient confidence to push the code to production.
For both manual testing and automated Selenium testing, real device testing is absolutely crucial in obtaining reliable results. Organisations prefer cloud-based testing infrastructure in order to avoid the prohibitive costs of setting up an in-house lab.