Continuous Integration vs. Continuous Deployment: 5 Key Differences

This is part of a series of articles about CI/CD

What Is Continuous Integration? 

Continuous integration, often abbreviated as CI, is a development practice that involves regular integration of code changes into a shared repository. Developers merge their changes multiple times a day, which allows teams to detect and resolve integration issues early. The idea is to prevent the ‘integration hell’ that occurs when developers work in isolation and integrate their changes at the end of a development cycle.

In a continuous integration environment, every code change triggers an automated build-and-test sequence for the given project, providing immediate feedback to the team. If an integration issue is detected, developers can address it right away. This practice not only helps in maintaining a consistent code base but also improves the efficiency of the development process.

It’s worth noting that continuous integration is not just about the tools or the automation but also about the culture. It requires a shift in mindset where developers understand the need for frequent code integration and the importance of immediate feedback. It demands commitment, discipline, and a willingness to rectify mistakes promptly.

What Is Continuous Deployment? 

Continuous deployment is an approach where every change that passes the automated testing phase is automatically deployed to the production environment. Unlike continuous delivery, where the final step of deploying to production is manual, continuous deployment automates this step, ensuring a seamless flow from the development stage to the production stage.

In a continuous deployment setup, the software is always in a releasable state. Whenever a change is made, it goes through various stages including integration, testing, and deployment, ensuring that the software is always ready for production. This practice not only accelerates the release process but also minimizes the risk associated with releases.

It’s important to realize that continuous deployment includes continuous integration as a mandatory component. It’s impossible to do continuous deployment without CI. So, while continuous integration provides a foundation of collaboration and rapid iteration, continuous deployment takes it a few steps further, completely automating the entire software delivery pipeline.

Continuous deployment also requires a cultural shift. It demands a high level of confidence in the automated testing and deployment processes. It necessitates a robust monitoring system to detect any issues that may arise in the production environment. And above all, it requires a commitment to maintaining a high-quality codebase at all times.

This is part of a series of articles about CI/CD

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Benefits of Continuous Integration 

Continuous integration, when implemented correctly, can offer several advantages to both the development teams and the organization as a whole:

  • Catches integration problems early and makes them less costly to fix. Since developers integrate their changes frequently, integration issues are identified and addressed right away, preventing them from snowballing into larger problems.
  • Fosters a culture of collaboration and shared responsibility. It encourages developers to work together, share their changes regularly, and contribute to a consistent code base. This not only enhances the team’s productivity but also improves the overall software quality.
  • Provides immediate feedback, leading to faster iterations. Developers receive instant feedback on their changes, allowing them to rectify any issues promptly. This enhances the efficiency of the development process and leads to quicker deliveries.

Benefits of Continuous Deployment 

Continuous deployment, like continuous integration, offers several benefits. Implemented correctly, it can significantly enhance the efficiency and speed of the software development process.

  • Allows for faster delivery of features: Since every change is automatically deployed to production, new features and updates reach the end-users more quickly. This not only results in happier customers but also gives the organization a competitive edge.
  • Reduces risks associated with releases: By deploying smaller changes more frequently, the scope of potential issues is minimized. Moreover, since the system is continuously monitored, any problem that arises is immediately detected and fixed.
  • Frees up the development team’s time: Since the deployment process is automated, developers can focus on what they do best—writing code.

Continuous Integration vs. Continuous Deployment: Key Differences 

1. End Goal

Continuous Integration

The primary goal of continuous integration (CI) is to ensure that software components integrated from different sources into a single central repository are working seamlessly. Developers regularly commit their code into this repository, which is then built and tested automatically. 

The objective here is to catch integration issues as early as possible. By integrating frequently, you can identify and address problems early, reducing the chances of encountering significant issues down the line.

Continuous Deployment

Continuous deployment (CD) aims to automate the software release process. It ensures that code changes made by developers are automatically prepared for a release to production. 

Unlike continuous integration, continuous deployment focuses on what happens after the code is integrated and tested. The goal here is to make the release process as swift and efficient as possible, allowing for more frequent and reliable software releases.

2. Infrastructure Requirements

Continuous Integration

Continuous integration requires a robust version control system to manage and track all the changes made to the codebase. It also requires a CI server that can monitor the central repository and trigger a build whenever a change is detected. Tools like Jenkins, Bamboo, and TeamCity are commonly used for this purpose.

Related content: Read our guide to ci/cd with jenkins.

Continuous Deployment

Continuous deployment, on the other hand, requires not just a CI server but also a deployment pipeline to handle the various stages of the release process. This pipeline needs to be configured to automate the deployment of changes to different environments (e.g., staging, production). Tools like Ansible, Puppet, and Chef are often used to manage this deployment pipeline.

3. Human Intervention

Continuous Integration

With continuous integration, the process of integrating and testing the code is automated and takes place as soon as a developer commits changes to the central repository. However, if the automated tests fail, it’s up to the developers to fix the issues. So while the integration and testing process is automated, resolving problems still requires human input.

Continuous Deployment

Continuous deployment takes automation a step further. If all tests pass, the changes are automatically deployed to production without any human intervention. This means that every commit that passes the automated tests is a potential release candidate. The only time human intervention is necessary is when an issue arises that the automated tests didn’t catch.

4. Testing Scope

Continuous Integration

The scope of testing in continuous integration is typically limited to unit tests and integration tests. These tests are designed to verify the functionality of individual components and their interaction with other components. They are fast, reliable, and can be run frequently without significantly impacting the development process.

Continuous Deployment

In continuous deployment, the scope of testing extends beyond unit and integration tests to include system tests, acceptance tests, and sometimes even performance and security tests. These tests are more comprehensive and aim to ensure that the software works as expected in a real-world environment. However, they are also more time-consuming and resource-intensive.

5. Feedback Loop

Continuous Integration

One of the key benefits of continuous integration is that it shortens the feedback loop. Developers receive immediate feedback on their changes through the automated tests. If a test fails, they are alerted right away, enabling them to fix the issue before it can impact the rest of the system. This rapid feedback loop helps to maintain the quality and stability of the software.

Continuous Deployment

With continuous deployment, the feedback loop extends beyond the development team to include the end-users. Since changes are deployed to production automatically, users can provide feedback on the new features or fixes almost immediately. This allows for quicker iterations and improvements based on real-world usage and feedback.

Related content: Read our guide to CI/CD as a service

CI/CD for Kubernetes with Spot by NetApp

Continuous Delivery has entered a new phase as more and more applications are migrating to microservices, with Kubernetes as the container orchestrator of choice for many. Kubernetes enables agility and faster software development cycles, but as release frequency increases, supporting delivery at large-scale becomes complex and inefficient. 

Spot by NetApp introduced Ocean CD as part of the Ocean suite for Kubernetes to address the specific challenges of modern delivery release cycles. Ocean CD provides complete deployment and verification automation in one fully managed solution, making it easy for users to execute deployments with high confidence. Key features of Ocean CD include:

Out-of-the-box progressive delivery strategies 

Canary and blue/green strategies are easy to define, automate and customize. Developers commit code, use any CI tool and Ocean CD detects the deployments, automatically initiating the assigned rollout strategy. 

Continuous verification automation

Ensure stability and quality of deployments even as release frequency increases. Routine verifications of deployments are conducted automatically and based on metrics from monitoring tools like DataDog and New Relic. 

Automatic rollback

When issues are detected, Ocean CD initiates safe rollbacks and automatically tunes infrastructure to meet changing requirements of workloads. Continuous improvements are made to application deployments based on metrics collected during verification processes.

To learn more about Ocean for Continuous Delivery read our blog post or visit the product page.