Continuous Integration vs Continuous Delivery vs Continuous Deployment
Continuous Integration and Continuous Delivery (CI/CD) are methods by which applications can be released regularly and automatically. With the CI/CD process, individual development steps during the development of applications can be automated and monitored in a coherent manner. In technical jargon, these steps are often taken together and called the CI pipeline.
In this blog post I would like to:
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Explain what continuous integration, continuous delivery and continuous deployment is
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Give you an overview of the difference between continuous delivery and deployment
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Show you the most important advantages of a CI pipeline
Let's get started!
What is continuous integration?
CI is the abbreviation for continuous integration. If a CI pipeline is configured correctly, changes in the code of a software or an app are merged into a shared source code repository (Gitlab or Github). Each change, a so-called commit, triggers a new build. Automated tests (unit-tests and integration tests) are then performed on the new build to identify whether anything has changed negatively due to the code changes. At the end of the pipeline, notifications (e-mail, slack, SMS) about the results of the tests (error, success or warnings) are sent to the developer. Ultimately we should always have a buildable-runnable version of our developed software or application.
The implementation of continuous integration prevents the chaos that often happens when you wait for too long and merge too many code changes into the release branch. CI automatically tests each commit to ensure that the application does not break when the code change is integrated into the main branch.
For Updraft we use Gitlab as a version control system of our codebase. Due to our agile development process, we commit at least on a daily basis to see our development progress.
What is continuous delivery?
CD is the abbreviation for continuous delivery or continuous deployment. The two terms are often used as synonyms, which unfortunately is not entirely correct. While both terms are about automating the further phases of the CI pipeline, they do not tackle the exact same issues. The difference between continuous delivery and deployment is explained further below.
The aim of continuous delivery is to sustainably integrate the code developed by the developers into a production environment. The developed code (bug fix or new feature) is automatically prepared for a new release into production which means code is uploaded to the repository, is built automatically and passes the automated tests. This new, working and already tested build or part of your application is then ready to be manually released into production.
The automated tests configured within the CI pipeline may include unit tests, load tests, integration tests, API tests or security tests. This helps developers to discover issues and bugs before updating production.
What is continuous deployment?
Continuous deployment is the next step to complete automation of the CI pipeline based on the already configured steps for continuous delivery. With the continuous deployment approach, every change in the code is automatically deployed to the production environment after the steps in the CI pipeline have been completed successfully. This can result in several daily deployments to the production environment for large projects.
There is always a business need for faster release (keyword: release velocity).
According to an article in TechBeacon, Amazon already made a production release every 11.7 seconds on average in 2015. Imagine what this looks like now, 5 years later and with even more advanced technology.
What is the difference between continuous delivery and continuous deployment?
The difference between continuous delivery and continuous deployment is that with continuous delivery, the deployment to a production environment is done manually. With the continuous deployment approach, the update to a production environment is performed automatically without the approval of a responsible, human person.
What is needed to set up a CI/ CD Pipeline?
It may look daunting at first, but it is actually quite easy to configure the CI/CD Pipeline. Here are the most important points you need to keep in mind:
Updraft supports most of these common tools as this works via API Upload - so far you can find the documentation for Jenkins and Gitlab CI on https://docs.getupdraft.com/continuous-integration.
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You need a version control system (Gitlab, Github, Bitbucket) to host and store your source code
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You need to write automated tests for each new feature and bugfix of your application
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You need a continuous integration and delivery service that can monitor the repository and run the automated tests for every pushed commit. Here is a list of the most common CI/ CD services:
Updraft supports most of the common tools as this works via API Upload. You can find the documentation for Jenkins and Gitlab CI on docs.getupdraft.com/continuous-integration.
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Your developers need to merge their code changes as often as possible, at least on a daily basis
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The team must start working with feature flags so that unfinished features do not break features on production
What are the benefits of continuous integration, delivery and deployment?
Often releasing the source code or parts of it to a production environment has the benefit of reducing the risk of failing with your product on the market. If you release your software regularly to the productive environment you will also get feedback about your product from your customers earlier. Thus you have the possibility to further develop with a value-oriented approach.
The benefits of a CI/CD pipeline are:
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New features and improvements get to your users faster
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Small incremental changes become measurable
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Newly developed code is automatically tested and it quickly shows if the already developed code still works (automated regression testing).
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It becomes transparent to all stakeholders and customers what has already been developed, and the whole team can see the progress on a daily basis instead of every month or quarter and can plan all further activities.
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You no longer have to be afraid to build and break something, because the integration tests will be done from the beginning
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Find a bug in your code and hide the bug with a new bug, that hides other bugs. With a CI/ CD pipeline, you can detect such bugs early and eliminate them before starting to develop new features
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Improve the quality of your code as well as the whole product
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Testability: The easier something is to test, the easier it is to make a statement about the quality
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Testing costs are massively reduced because hundreds of tests are already performed automatically so that the QA-team can focus on quality assurance instead of quality control.
Conclusion
With a properly configured CI/CD process at the beginning of a project, individual development steps during the development of applications can be automated and monitored in a coherent manner, which leads to an increased total quality of your software. Often, releasing to a productive environment has the advantage that the software or the increment of the software is in the market faster, which increases the value of your product and may be a competitive advantage.
We generally recommend configuring a CI Pipeline in every project. Don't be afraid of the initial effort, you will quickly realize how much you will benefit from it over the duration of the project.
In the next few blogs, we will show you how to connect Jenkins and Gitlab CI with Updraft to automate your app distribution.