Continuous Integration and Continuous Delivery/Deployment, commonly termed CI & CD is a modern software development practice. In CI/CD, small incremental code changes are introduced in the existing application. It is a reliable and effective way of upgrading the current application. In this blog, we discuss everything you need to know about Continuous Integration and Continuous Delivery/Deployment (CI/CD).
A team works parallelly on different aspects of application building. The members integrate their work at least once a day to avoid “integration hell” at the end of the project. CI is the practice of merging codes now and then.
Once code is committed, the software needs to be built and tested. In large teams, the code is executed by some developer or the other at different times of the day. Each code needs to be tested and then sent in for deployment. If the deployment process is successful, the code is pushed to the production stage. This process of committing, testing, deploying, and finally producing is ongoing and continuous. Hence the name - Continuous Integration & Continuous Deployment (CI/CD)
Read on to understand the CI/CD process and CI/CD pipelines.
CI/CD falls under DevOps, i.e., development and operations. It merges the processes of continuous integration and continuous delivery/deployment. CI/CD tools automate the human intervention process of code production from testing to deployment and infrastructure provisioning. With CI/CD pipeline, developers only have to push the code. The code changes are automatically tested and pushed out for deployment. With the help of CI/CD, downtime can be minimized, and software updations can be quicker. This is a reliable and efficient way of pushing code without bugs.
By implementing the CI & CD best practices, the DevOps team can focus on meeting business requirements without worrying about the quality and security of the software. Now that you know what CI/CD is let’s see the process of CI & CD in detail.
With a huge team working on the same project, software integration at the end can bring in multiple integration issues. In Continuous Integration, developers push code to the main branch of a shared source code repository after it is committed. The code is automatically merged with other branches and tested. This process allows the identification of errors and security issues at a much earlier stage of the software development lifecycle.
Continuous Integration helps in identifying errors and security issues in earlier stages of the software development lifecycle.
Continuous Delivery works side by side with Continuous Integration. Continuous Delivery (CD) facilitates infrastructure provisioning resulting in a smoother application release. Continuous Delivery works in the final stages of development.
Continuous Deployment eliminates the human intervention in code deployment to upgrade any application. The DevOps team is responsible for setting the criteria for code releases ahead of time. The code is automatically deployed into the production environment when those criteria are validated. This allows users to enjoy the latest features of any application at lightning-fast speed.
Now that we understand all these terms clearly, let's look at what a CI/CD pipeline looks like and the different stages of it.
CI/CD pipeline is nothing but a collection of tasks that should be carried out for code deployment.
The CI/CD pipeline need not be similar for every team. You can formulate your pipeline based on your requirements.
Once you succeed in making the pipelines, you do not require any human intervention. You can execute them automatically.
Let's have a look at what different stages of a typical CI/CD pipeline includes:
The CI/CD pipeline is an automated system where the code is processed. The pipeline can be customized and will look different for every organization. It must be built based on the company requirements. The CI/CD pipeline has four main stages, namely:
1. Source stage
CI/CD pipeline has a code repository. Whenever you push a new code, it lands in the source stage. The code repository is triggered by this, sending a notification to the existing code for a merger.
2. Build stage
Code mergers or compilations occur in the second stage, i.e., the build stage. If the code fails to pass this stage, you need to check it for issues. The build stage ensures that any fundamental issue is flagged early.
3. Test stage
As the name suggests, the test stage executes and validates the code. These tests are automated. The software team needs to set up the test stage steps beforehand to ensure a seamless testing process. The test stage ensures that all the bugs are removed and do not end in the final product. Developers are responsible for writing these automated tests in the early stages.
4. Deploy stage
Once your code has passed all the last stages, it is ready to be deployed and go live. The automation of these steps ensures a safe and bug-free code for the end-user.
- Complete deployment lifecycle time:
It refers to the time taken from the first to the last stage, i.e., from the build stage to the deployment stage. This metric will help you understand the bottlenecks in the process. It will also give you insight into the development time and scope of improvement.
- Frequency of development:
The higher your frequency of releasing the code, the lesser the errors. This metric will help you identify your team efficiency and improve upon the same.
- Failure rate:
Failure rate refers to the number of times the code was successful. If you face code failure time and again, it is a bad sign and needs attention.
- MTTR AND MTTF:
MTTR - Mean time to recovery stands for the amount of time your team required to cope with an issue.
MTTF - Mean time to failure refers to the time your team took to fix a bug and move on to the next.
These metrics help you understand your team's response time in case of issues and bug fixes.
Continuous Integration is a process that allows big teams to merge codes without any hassle. Continuous development refers to code merger, compilation, testing, and deployment automation. It cancels out human intervention and results in effective, reliable, and secure code. The method of CI & CD ensures fewer bugs and a better end-user experience.
There are a few performing factors that you must keep in mind to ensure that your process is working at its best. It is crucial to track the time taken by your team to take the process from coding to deployment, i.e., measure the lifecycle time. As the testing process is automated, you must monitor how much time is required to fix and tackle the bugs.
Continuous Integration and Continuous Development/Deployment is an excellent way of updating the application. It ensures the best quality products for your end-users.
i. Is CI CD the same as agile?
Ans. CI/CD or continuous integration and continuos delivery is a software development practice wherein large teams keep phishing small code set for integration and testing. On the other hand, Agile is a set of frameworks and practices. It facilitates collaboration wherein a cross-functional team focus on specific issues and tools.
ii. What is CI and CD in Jenkins?
Ans. CI (continuous integration) and CD (continuous delivery) are two important concepts in Jenkins. CI is the process of integrating new code into a shared repository on a regular basis. CD is the practice of automatically deploying changes to a production environment as soon as they are ready, which minimizes downtime and risk.
iii. What is the purpose of continuous integration?
Ans. - Continuous Integration (CI) is a software development practice. When large teams work on different workflows and features of an application, they push feature based code in the pipeline. The pushed code is then tested and deployed automatically through the system.
iv. Why is CI important in the software development lifecycle?
Ans. The traditional methods of code deployment used to be painfully slow because code integration at the very end lead to multiple errors and bugs. CI has become an integral part of software development because it is fast, flexible, ensures quality assurance and reduces workload of developers.
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