Jenkins — Industry Use Cases.
In many projects, the product development workflow has three main concerns: building, testing, and deployment. Each change to the code means something could accidentally go wrong, so in order to prevent this from happening developers adopt many strategies to diminish incidents and bugs. Jenkins, and other continuous integration tools (CI) are used together with a source version software (such as GIT) to test and quickly evaluate the updated code.
Jenkins is a popular self-contained, open-source automation server to perform continuous integration and build automation. Its elementary functionality is executing a predefined list of phases or jobs.
Each phase is monitored and allows you to stop the entire process and the change will be reported to the user by Jenkins. In large companies, it is common for multiple teams to work on the same project without knowing what the other teams are doing on the same code base. Those changes can create bugs that will only be revealed when both codes are integrated into the same branch. Since Jenkins can run its predefined jobs for every commit, it will be able to detect and notify developers that something is not right and where it is.
Thousands of add-ons can be integrated with Jenkins, they provide support for different types of build, version control systems, automation, and more. It can be installed through native system packages, Docker, or be run by any machine with a Java environment installed.
Jenkins is often used for building projects; running tests to spot bugs, to analyze static code, and deployment. It also executes repetitive tasks, saves time, and optimizes developing processes.
Beginning with the second version, Jenkins introduced Pipelines, a different way to programmatically define a project build workflow. Before pipelines, the CI description was defined and stored outside the repository—it was designed to evaluate—now, with Pipelines, CI files are present in project source code. The file describes the workflow through a language which can be used to create different jobs in sequence or in parallel.
Jenkins use cases
Continuous Integration (CI)
Continuous integration is a practice that forces developers to frequently integrate their code into a central repository. Instead of building out new features to the end without any quality measurement, every change is tested against the central repository in order to anticipate errors.
Every developer commits daily to a shared mainline and every commit triggers an automated process to build and test. If building or testing fails it can be detected and fixed within minutes without compromising the whole structure, workflow, and project. In that way, it is possible to isolate problems, solving them faster and provide higher-quality products.
As a job executor, Jenkins can be used to automate repetitive tasks like backup/restore databases, turn on or turn off machines, collect statistics about a service and other tasks. Since every job can be scheduled, repetitive tasks can have a desired time interval (like once a day, once a week, every fifth day of the month, and so forth).
Continuous Deployment (CD)
Continuous deployment, also known as continuous implementation, is an advanced stage of continuous delivery that the automation process does not end at the delivery stage. In this methodology, every change that is validated at the automatic testing stage is later implemented at the production stage.
The fail fast strategy is always of the utmost importance when deploying to production. Since every change is deployed to production, it is possible to identify edge cases and unexpected behaviors that would be very hard to identify with automated tests. To fully take advantage of continuous deployment, it is important to have solid logging technology that allows you to identify the increasing error count on newer versions. In addition, a trustworthy orchestration technology like Kubernetes that will allow the new version to slowly be deployed to users until the full rollout or an incident is detected and the version is canceled.