Continuous Integration (CI), Continuous Delivery (CD) and Continuous Deployment (CD) are three processes that automate integrating software development into a product and deploying the modified product to test and production environments.
In this post, we’ve gathered insights from two of our favourite experts to expand on the considerations and top queries around CI/CD/CD to help junior developers and anyone who is curious about getting started with Continuous Integration, Continuous Delivery and Continuous Deployment.
Our first expert Mallaidh Mleziva of Flexagon, explained in detail the three components that makeup CI/CD/CD in her response:
What Is Continuous Integration (CI)?
Continuous Integration (CI) is a restructuring of the software development and delivery process by breaking down large, bundled projects into smaller discrete parts.
It involves the frequent updating of code to a shared source control repository, after which they move through automated builds and testing in lower environments. The focus of continuous integration is development and testing. Frequent updates and synchronizations allow for automated build processes and testing to be triggered.
Limiting the number of manual touches, continuous integration helps to speed the cycle, and mitigate the risk involved with less-frequent integration testing of the code.
What Is Continuous Deployment (CD)?
Continuous deployment is the process of deploying any software that passes an automated testing phase to the production environment without additional manual inputs or configuration.
By automating deployments, teams can move software to production in a fast, reliable manner. Updates and releases are more frequent as manual tasks are eliminated. Additionally, this decreases the risk of human error as packages have passed pre-defined tests before final deployments.
If errors do occur, teams can establish version control to rollback if necessary. Time spent on troubleshooting and resolving outages decreases significantly, allowing teams to focus on higher-value endeavours that have greater impacts on the business.
What Is Continuous Delivery (CD)?
Continuous Delivery (CD) is the process of ensuring code changes can be safely deployed at any time. While continuous integration focuses on the build cycle of software development, continuous delivery (CD) is all about delivering new capabilities or enhancements to the end-user as quickly as possible.
Automation plays an enormous role in achieving continuous delivery. Automating continuous testing and other quality checks act to ensure that bugs are identified and corrected before updates are deployed.
By automating these next phases of the process, continuous delivery further decreases time to market and allows end-users to get new capabilities and enhancements as quickly as possible. Additionally, you can get feedback sooner and fix any errors.
What Is CI/CD?
The term CI/CD refers to the combined practices of bringing together all of the core principles of Continuous Integration & Continuous Deployment/Delivery.
This idea aims to account for any gaps which may have been left by development or operations during the course of a project's launch.
Our next expert, Anthony Amos, of Anthony Software Group, generously contributed his answers to the following top eight most commonly asked questions on this topic below.
Continuous Delivery vs Continuous Deployment
Continuous Deployment and Continuous Delivery both serve similar purposes in that they eliminate human intervention and error when delivering a software product to an audience.
The formal distinction is that Continuous Delivery automates software delivery to closed audiences of testers and approvers before exposing it to the public. These audiences use non-production environments with names like testing, staging, alpha-test, beta-test, or pre-production to validate the changed product.
On the other hand, Continuous Deployment automates testing and approval and then deploys the changed product to production without human intervention. This enables features to go from developers, through the pipeline, and out to production without stopping, barring any failed tests.
Some organizations use Continuous Delivery, and then after human approval, they use a Continuous Deployment process to automate the release to production.
What Is The CI/CD Pipeline?
The CI/CD Pipeline is a process designed to integrate the essential CI & CD automation steps into a cohesive solution. So with a CD/CD Pipeline in place, development team members can get new code safely into the final product while eliminating manual intervention and errors along the way.
Why Do We Need CI/CD?
CI will integrate code, analyze it, update external resources, run test suites, among other things. The CI results will advise the team whether changes can safely and successfully be integrated into the product. CD will deploy the integrated product to an appropriate test/production environment so that stakeholders can use it.
CD will also rollback a problematic version. It’s called continuous because it happens continuously in real-time as opposed to on a schedule. A well designed CI/CD pipeline provides confidence that you did properly build and deploy an updated product. This eliminates mistakes and enhances confidence. It also eliminates conversations that start with the following phrases:
- It worked on my machine
- I didn’t know this change would affect...
- I forgot to write a test case to cover...
- We can’t roll back because...
- What Does The CI/CD Pipeline Mean For DevOps?
A CI/CD Pipeline creates a clean turnover from development to operations and support teams.
When those teams take over product support from development, they can have greater confidence that the product has been vetted and properly deployed. Also, any supporting resources like databases, LDAP directories, automated documentation, etc. in the right environments are synchronized with the deployment.
What Are CI/CD Tools?
CI/CD Tools automate the execution of code integration or deployment steps. The steps needed to store, build, test, and deploy a product does vary a lot, even within the same organization, so the tools also vary.
CI requires one or more compilers, code analyzers, automated testing suites, script runners, etc.; and there is a wide selection of tools in each category. Tool selection is a serious process requiring teams to standardize so they don’t create problems.
How Can The Process Of The CI/CD Pipeline Be Done In A Real-Time Environment?
A CI/CD Pipeline is what makes these types of deployments feasible because machines do all of the testing and deployment work.
If product changes are released in real-time, then the testing requirements become extremely demanding and rigorous.
This is because changes require extensive scrutiny and scenario validation as well as a comprehensive deployment strategy so that problem releases can be independently rolled back.
How Do You Track Tables Deployed In Production Using CI/CD?
Any database changes must use scripting to perform any table or index changes and roll-backs.
Specific tables, down to the field data type level must be associated with a particular code version so that it can be synchronized with the right environment, and follow-on changes reflect all affected code bases. Ideally, a service-based approach is used, so there is only one code base associated with any database components, but older code might not have used that approach. In those cases, code should be refactored to accomplish these development practices.
How Do You Integrate Your Framework With CI/CD?
The software engineering framework should mirror the CI/CD pipeline so each developer can replicate each pipeline step. It is pretty common that developers need to update scripts in the pipeline, and those scripts also need to be tested. So integration requires educating everyone on the development team. It also functions best when team members are cross-functional, meaning no dedicated developers and testers; instead, everyone has a hand in everything from start to finish. Dedicated teams of developers, testers, analysts, and release staff make it much harder to use CI/CD.