Continuous Delivery vs. Continuous Deployment: Understanding the Difference

In today’s rapidly progressing world, new software is developed and introduced every day. The need for automation and software updates has created a huge gap in the development and delivery of software products. However, getting a clean software product quickly and readily out to the clients is of utmost importance. To achieve this, software development teams need to produce new code quickly and update the existing ones frequently. The current scenario does not provide developers with the luxury to analyze and investigate features and code with a long and slow process. This can cost software companies not only in terms of money but in terms of time too. Today, clients are more interested in how quick the turnaround time is after they have requested a software product or a feature update.

This calls for a balance among speed, need, efficiency, and precision of the software development and delivery process. This is achieved by the arrival of Agile development. The Agile development methods have allowed teams to optimize their way of planning, automation testing, and implementation. The code changes can be initiated in smaller increments and faster development cycles. However, developers need to give an ample amount of attention to the development of source code rather than on delivery or deployment. This issue was solved by the propagation of the Continuous Integration and Continuous Deployment/Delivery pipeline.

CI/CD has created a revolution in software development making developers more responsive towards client needs. Continuous Integration acts like glue that holds code all together via version control systems etc. and Continuous Delivery and Deployment are more concerned with the production environment setup and application end processes. But, the difference between Continuous Delivery vs. Continuous Deployment is something people have a hard time understanding.

In this article, we will take a deep dive into differentiation these terms – Continuous Delivery vs. Continuous Deployment. But first, let’s have a brief understanding of Continuous Integration.

What is Continuous Integration?

Continuous Integration is the nucleus of automation of project builds. Continuous Integration is a practice to merge source code from version control systems like Gitlab, Github, Bitbucket, etc. to a shared main branch or mainline several times a day. Continuous Integration creates a repeatable, consistent, and always available build process. Each merge triggers an automated build and testing sequence for a project.

The CI(Continuous Integration) process is not the same for every software source code, but the process follows similar stages for every software build.

The broad view of the stages involved in Continuous Integration is :

1. Plan Stage: Writing code for any use-case, results in a software application. This application development process is first planned by software architects and then a document is created. This document guides the software development team, with the hows and whats of development.
2. Code Stage: The Code Development process comes under this stage, the code reviews, walkthroughs, etc. are done to ensure development is on the right track. The code base with different features is developed by the development team. The code is then pushed to a version control system such as Github, Gitlab, etc.
3. Build Stage: After the code development, developers submit their segment of code at a time. These code segments are sent to the build server and are managed by version control systems. Depending on the programming language, the code first complies with a single branch. If required the code is packaged to a Docker container.
4. Test Stage: In this stage, different sorts of tests are conducted such as automated tests, manual tests, etc. Unit testing is done to verify a specific unit of code. Other automated tests help in checking the UI behavior, application performance, API reliability, and much more. This stage acts as a net that prevents issues to be reached to the end-users. As a result, the code shipped is more effective and bug-free.

Another crucial thing to be aware of is where the continuous integration process ends, continuous delivery/deployment processes begin. If you don’t want to overburden your continuous integration process, follow the best practice of adding unit tests and artifact scans to it. Tests that take application infrastructure into account are best to be saved for continuous delivery vs. continuous deployment processes.

What is Continuous Delivery?

In the Continuous Delivery(CD) process, all the code changes are automatically deployed to either testing or production environment setups. This is an extension to continuous integration processes. Continuous delivery focuses more on the release schedule and release strategy. This automates the release process as well.

The automated process of continuous delivery requires at least one step with human intervention. This manual step is of approving and initiating a deployment to production. The typical set of steps included in the continuous delivery phase are:

1. Pushing Code to Staging Environment: After the testing stage has been completed, the code is staged for deployment into the production environment. The source is then sent for some Integration tests, Application Acceptance tests, etc.
2. Application Acceptance Testing: Different sets of heavy tests are run, and the application is tested. After the testing is once done, the code is deployed to production.
3. Deploying to Production: Release to the production environment can be done manually. This can be daily, or your team can confirm the best schedule for its purposes when it comes to continuous delivery.

The desired outcome of continuous delivery is that anyone with sufficient privileges to deploy a new release can do so at any time or with a few clicks. This also means that the decision to initiate a release is taken by a human, and only after that, the continuous delivery process takes place. However, this is sometimes required, as human intervention can detect and work on new releases according to the production environment, this also acts as a final check in the CI/CD pipeline.

What is Continuous Deployment?

Continuous Deployment takes a further step from continuous delivery. This practice ensures that the code changes are automatically released to the production environment. The goal here is to release a new version whenever a developer makes changes, this process automatically gets those changes to the end-users. Continuous deployment first focuses on automation, unlike continuous delivery which is more focused on release strategy.

The procedure of Continuous Deployment is:

1. After the evaluation of all the pull requests from different developers is completed, a build is constructed via merging the code and resolving the conflicts aroused; then unit testing is attempted under continuous integration process and the developer’s job typically ends here.
2. A CI/CD service takes over from there by running heavy sets of tests, such as Integration tests, System Tests, Application Acceptance tests, etc. and the test suites are engineered to qualify the builds and automated continuous deployment process.
3. This service then deploys the code to production or production-like environments, while keeping the DevOps team informed about the outcome of every important event. The whole process is automated and elastic.

Continuous Deployment as the name suggests is a bit more focused on automated deployment; Which is the actual installation and distribution of bits. In simple words, it focuses on the automation to deploy across environments or clusters, in regards to the traffic. In the continuous deployment process, the source code is run and maintained in a simulated environment, ensuring the ultimate quality to be taken in consideration. Real-time monitoring of this environment is done to keep track of any arising issue and these issues are resolved quickly.

Difference between Continuous Delivery vs. Continuous Deployment:

This question is often asked – What is the difference between continuous delivery vs. continuous deployment? What is CD in CI/CD? Does it stand for continuous delivery or for continuous deployment?

Well, the answer is both. Depending on the workflow and project requirements, the DevOps and software development team would pick the best that fits them and the software product. Both continuous delivery and continuous deployment depend on the real-time infrastructure of the project. The difference between Continuous Delivery vs. Continuous Deployment is highlighted below:

From the above differences, understand that continuous delivery and continuous deployment have slightly different goals. Continuous delivery has an overlap with continuous deployment on the deployment front, but we need to be thoughtful about not overburdening the deployment systems. After all, delivering a quality product with the alignment to the CI/CD pipeline is the ultimate goal.

Benefits of each practice:

Both continuous deployment and continuous delivery depend on real-time infrastructure and application monitoring tools to maintain the software product and uncover any issues that have not been found before release. But both continuous delivery and continuous deployment count for different benefits in different cases. Let’s have a look at their beneficial aspects one by one.

Continuous Delivery:

1. Continuous delivery makes the software release process more efficient, rapid, and secure. This is because the release is completed regularly. Even, end-users do not notice changes, releasing on a smaller scale several times a day is often more effective than a giant released on a weekly or even longer timescale.
2. The clients and end-users are more receptive to small changes than large ones. These smaller changes are more stable, and controllable. This makes the continuous delivery process more reliable.
3. Failed test cases can arrive in any and every environment at any time. Thus, the CI/CD pipeline includes a feedback channel to report these failures to developers quickly. These feedback loops must be as short as possible to compete against a steady stream of releases. Continuous delivery shrinks these feedback loops between developers and clients. Developers can then put the failed tests into the backlog to repair at a later sprint – or if the failure is critical, repair right away.
4. The process of preparing for deployment is significantly minimized. As the code is released in smaller chunks, the environment can release code more often. This decreases the need for the preparation of a pre-production environment.
5. A human intervention needed in the continuous delivery release process acts as a validation to the steps that safely get all changes of source code into the production environment. This helps the business team to deliver updates to clients immediately and frequently.

Continuous Deployment:

1. Continuous deployment makes the deployment process flawless without compromising the security of software products. The automated infrastructure ensures that each part of the deployment quickly and reliably.
2. Continuous deployment also allows software development and DevOps teams to commit to a fully automated CI/CD pipeline, including deployment to production. By enabling an automatic push of new releases into production. You don’t have to worry about “big releases” and receiving feedback directly from end users on the software product.
3. This enables you to have an increase in overall productivity. The CI/CD pipeline has the continuous integration processes intertwined with the continuous deployment process and the whole CI/CD process is automated, which results in a unified pipeline.
4. The existing DevOps tools and scripts can be integrated with the automated CI/CD pipeline into a proper flow and can also be integrated for automated testing in CI/CD pipeline. The reusability is increased by the automation and continuous deployment process.
5. You can easily scale from a single software application to an enterprise IT portfolio through the process of continuous deployment. The automated CI/CD pipeline helps to automate repetitive tasks and can enable shipping of both cloud-native as well as traditional applications.

Challenges of each practice:

With the fast pace development of software products and applications, the CD(continuous delivery vs. continuous deployment) processes are crucial for a quick, scalable, reliable, and automated CI/CD pipeline. This also adds some challenges to the CD processes; these challenges are listed as following:

Continuous Delivery:

1. Efficiency: The continuous delivery process requires efficiency. This process should be efficient without bothering time. Human intervention sometimes makes the continuous delivery process less efficient when an automated CI/CD pipeline is constructed.
2. Achieving tight deadlines: An enterprise in the IT industry requires the completion of software projects in tight deadlines and a tight work-frame. The continuous delivery process has to cope up with tight deadlines and provide reliable release plans, both at the same time.
3. Non-essential revisions and delays: During the CI/CD process of a software product, poor product-specific communication of teams may lead to non-essential revisions as well as deployment delays.
4. Excessive human intervention: Excessive manual work could result in an increased budget to have more software developers. This could in return cause losses and delays to the product delivery.
5. Inadequate coordination of continuous integration and continuous delivery: The continuous delivery process comes after continuous integration; But in an automated CI/CD pipeline, both processes have collaborated. This collaboration and communication if not attempted appropriately can result in delays and unnecessary losses.

Continuous Deployment:

1. Continuous planning is required: Continuous deployment is a fully automated process and requires recursive planning to achieve fast and frequent releases to the production environment. The test suites should also be good enough and planned appropriately to automate the testing process, alongside the deployment process.
2. Appropriate alignment between business context and application development and deployment: The automated continuous deployment process requires business context, software application development, and deployment to be in line, to avoid failures and non-essential releases.
3. Wrong processes may get automated first: As mentioned before, proper planning and construction of an automated continuous deployment process are needed. If any wrong process gets triggered then this could result in long delays and reconstruction of the whole process.
4. Good Testing culture needed: The testing culture for the continuous deployment process should be good as the quality of the test suite determines how good software releases are. That implies that the test suite should be good enough to qualify builds and automatically deploy them.
5. Releases require assurance: The releases from the automated CI/CD pipeline, in regards to the continuous deployment process, need to be assured by the marketing team, support team, and other departments. The releases must be continuously linked to the software map.

How are Continuous Integration, Continuous Delivery vs. Continuous Deployment related to each other?

A typical CI/CD pipeline begins with the continuous integration process. This allows developers to push and integrate code changes into a shared repository hosted by the version control systems such as Github, Gitlab, etc. This also ensures that the source code of the required software product is continuously tested, that developers are not duplicating efforts from other developers and that the integration into the shared codebase happens more smoothly.

After the continuous integration phase, the production moves on to either a continuous delivery phase or a continuous deployment phase. The transition between continuous integration to continuous delivery or deployment is generally automatic, which includes automated testing at the unit, integration and system levels.

But, before choosing between continuous deployment or continuous delivery, there are some constraints to be taken care of. Some of these constraints are the following:

• Market conditions, and regulatory compliances – Generally, these regulations restrict IT firms from making use of some processes of continuous deployment, depending on the business requirements and circumstances.
• Project requirements and deadlines –  Project requirements in regards to Quality Assurance, budget, automation etc. can be an element to look upon for the selection between continuous delivery vs. continuous deployment. Also, tight deadlines may be a deciding factor in choosing between continuous delivery or continuous deployment.
• The levels of DevOps concepts implemented – There are some levels defined in an IT organization.These levels in an IT firm also dramatically influence the usage of continuous deployment or continuous delivery for the required CI/CD pipeline.

Most organizations ought to move the production to continuous delivery then to continuous deployment. The code changes then go under multiple fixes and a  feedback loop before being pushed into a production-like environment. These feedback loops are required to be as short as possible.Whereas, in continuous delivery, the team decides what and when to deploy new updates to the customers.

The continuous deployment process can take a step further, that is being completely free from human interference. It is considered as a special case of continuous delivery.  Thus, these two concepts, continuous delivery vs. continuous deployment do not share the same definition, yet they have a mutual goal of automating and streamlining the deployment process. Sometimes, instead of choosing either one; continuous delivery is combined with continuous deployment to exploit the benefits from both practices to the fullest. However, continuous Integration practice will always remain the first one to be triggered in an automated CI/CD pipeline.

Continuous Delivery vs. Continuous Deployment – CI/CD implemented right by LambdaTest:

Continuous Delivery vs. Continuous Deployment is a quest for every DevOps developer, QA engineer, and tester. But companies often choose continuous delivery over continuous deployment, or they combine both of the practices. This entails a lot of processes starting with continuous integration to testing, and deployment processes. The DevOps team is to be in direct contact if any bug or issue is encountered in the CI/CD pipeline. This requires the team to provide attention to several factors such as the following:

• Whether the Development team and DevOps team are heading in the right direction?
• Business requirements are transformed to execution specifications appropriately or not?
• The CI/CD implementation follows market compliances or not?
• How to implement version control via systems like Github, Gitlab, and Bitbucket? Which is a cornerstone of the CI/CD pipeline that enables developers to collaborate on a shared codebase easefully?
• How to implement automation testing in CI/CD pipeline? How to go for cross-browser testing?
• How to implement CD processes?

There are a lot of topics that require the proper attention of developers and testers before implementation of the required CI/CD pipeline. These concerns can be taken care of by a great tool, LambdaTest.

LambdaTest is a cross-browser testing tool, which provides integration with numerous CI/CD tools such as Bamboo, Azure, Teamcity, etc. You can learn more about the integrations with CI/CD tools by visiting here. This also helps in fast-tracking a robust delivery pipeline for pacing up your go-to-market launch. This tool makes automated testing a seamless experience for you and your team. Automated tests provide more thorough validation, and Developers can update and locate issues before the release is public. Additionally when incorporated with automated releases, it establishes an appropriate and mechanized CI/CD pipeline.

 You can monitor and report bugs and issues very easily with LambdaTest, via the help of a meaningful Dashboard. This also provides integrations with Slack, Microsoft Teams etc. that helps the team members to be in a communication and brings the CI/CD process on the same page for every DevOps developer, tester or QA engineer.

Summing – up!

CI/CD makes it easier for teams to stay organized and makes fast delivery of software products to the clients. The main and most obvious benefit of CI/CD is that it helps in bringing your software application to the market quickly while continuing to meet the needs of clients by enabling them to roll out new features and updates quickly and efficiently. Several tools can help in enabling CI/CD processes and its automation testing with a smooth transition, But understanding the difference between continuous delivery vs. continuous deployment should be the first and the foremost requirement for the DevOps team implementing automation testing in CI/CD pipeline.

Whether your team integrates continuous deployment or continuous delivery into the CI/CD pipeline, both are great practices to ensure that your team stays up to date on releases and keeps the end-users happy. From planning to constructing, the most important part is testing, LambdaTest helps to achieve this goal effectively and reliably. The testing of a CI/CD pipeline should be done continuously and thoroughly. Then, the workflow moves on to the release of the source code to the production, deploys the changes to the live environment, operates and monitors the release to note any elements that should be fixed or upgraded.

The difference between Continuous Delivery vs. Continuous Deployment is like a jigsaw puzzle to a lot of developers, but I hope this article would have fairly helped you in solving this puzzle. In case you have any questions, feel free to reach out to us, and would love to have your feedback.