DevOps is an approach that aims to automate processes between development teams and systems operating teams to enable them to develop, test, and deliver software faster and more reliably. It consists of two key functions of a company specializing in application development. The term DevOps was born from the union of the two words "Development" and "Operations" to promote better communication between the two teams.

How was the approach born ?
This approach arose out of a need for communication between the two development and operating teams. Indeed, before the appearance of DevOps, the development team is in charge of collecting business requirements and developing them. It then tests the application or the software. If the tests are validated and the application meets the needs, it passes to the operational team. This caused problems because there was no interaction between the two teams, no team could know the difficulties that each could meet.

The principle of DevOps:
DevOps is represented in the form of a life cycle where the phases of project and monitoring are successive. Indeed, it is used to have feedback from customers to be able to immediately correct and modify software or web applications developed on the one hand and have a global view of development projects and allow teamwork to optimize costs and speed of implementation of the product or service.

To avoid manual and slow processes, teams use a set of technology practices and tools to quickly and efficiently deploy and innovate to their customers and, of course, to better manage complex environments.

The different phases and tools of DevOps :
Generally, DevOps is illustrated as an infinite loop which indicates that the order of the phases is not very important.

1- Planning
The planning phase is a phase that allows you to plan and define the requirements of an application, manage the various features, and identify bugs. This phase is very general and can include many activities. We find several tools that can be used in it such as : Redmine, Trello, Taiga, JIRA and  Mantis.

2- Creation
This step includes the design, coding, and configuration of the software development process as well as the performance quality controls. For this phase, we find several vendors such as : Bitbucket, GitLab, GitHub and  CFEngine.

3- Verification and Continuous Integration / Continuous Deployment
The verification phase makes it possible to test the functionality of the application to ensure the quality of the software or the application. Indeed, several tests can be applied in this phase such as acceptance tests, security and vulnerability tests and performance tests. For example, OpenQA is an automated test infrastructure for graphical user interface (GUI) applications. This tool complements traditional scripting tests and output controls. We also find Jenkins one of the most commonly used platforms for continuous integration / deployment. And in the same way, there are also other solutions, like Travis CI and  Concourse.

4- Automation of deployment and configuration
This phase is essential in the DevOps approach. To automate development and configuration, developers have a variety of solutions such as :  Chef, Puppet, Juju and  Ansible.

5- Management and monitoring
After the deployment step, applications are managed and monitored to better identify issues. All the information coming from this step has impacts on the plans for changes and new delivery cycles.

Finally, DevOps is not just a trend, but rather it is a well-defined set of practices that can make the investment profitable and unify both development and operations teams.