DevOps is a process/methodology that is practiced by the development team and operation team engineers in collaboration from inception to the end stage of the product. In a way, DevOps defines an agile relationship between operations and Development. 

There are seven phases of the DevOps lifecycle as given below:

1) Continuous Development

The planning and coding of the software are involved in this phase. It is the planning phase that decides the vision of the project. There are no DevOps tools that are required for planning, the developers start with the development of code in this phase.

2) Continuous Integration

This is one of the most important stages in the entire DevOps lifecycle. The software developers are required to commit changes to the source code more frequently (maybe on a daily or weekly basis). Every commit is built, this helps in the early detection of problems if any. Building code involves not an only compilation, it also includes unit testing, integration testing, code review, and packaging

The new feature code is continuously integrated with the existing code. It is therefore a continuous development of software. The updated code in then integrated continuously and smoothly with the systems to reflect changes to the end-users.

The very popular tool used in this phase is Jenkins. Jenkins is integrated with the GIT , so whenever there is a new commit in GIT, then Jenkins fetches the updated code and prepares a build of that code, which is in the form of an executable file. Then this build is forwarded to the test server or the production server.

3) Continuous Testing

In this phase the developed software is continuously testing for bugs. For continuous testing, test automation tools such as TestNG, JUnit, Selenium, etc are used. These test automation tools allow QA engineers to test multiple code-bases in parallel to ensure that there is no flaw in the functionality. Docker Containers can be used in this phase for simulating the test environment.

This entire testing phase can be automated with the help of one of the famous Continuous Integration tool called Jenkins.

A lot of time and effort for executing the tests is saved with automation testing. Reports can also be generated which is a great advantage. Execution of the test cases can also be scheduled at predefined times. Once the testing is completed, the verified code is continuously integrated with the existing code.

4) Continuous Monitoring

Monitoring is one of the important phases that involves all the operational factors of the entire DevOps process. The important information is recorded and carefully processed to find out trends and identify problem areas. The integration of monitoring is done within the operational capabilities of the software application.

5) Continuous Feedback

The software application development is improved by analysing the results from the operations of the software. The critical phase of continuous feedback is carried between the operations and the development of the next version of the current software application.

6) Continuous Deployment

In continuous deployment phase, the code is deployed to the production servers. It is essential to make sure that the code is correctly used on all the servers.

The new code, that may have bug fixes or feature enhancement, is deployed continuously, and configuration management tools play an essential role in executing tasks frequently and quickly. Some of the popular tools which are used in this phase, such as Chef, Puppet, Ansible, and SaltStack.

Containerization tools also have an important role to play in the deployment phase.  Docker is one of the popular tool that is used for this purpose. With the help of these tools onsistency across development, staging, testing, and production environment is produced. They also help in scaling instances softly.

With the help of containerization tools consistency is maintained across the environments where the application is tested, developed, and deployed. The production environment package and replicate the same dependencies and packages used in the testing, development, and staging environment, so there is no chance of errors or failure.

7) Continuous Operations

DevOps operations are based on the continuity with complete automation of the release process and helps an organization to speed up the overall time to market continuingly.