Below image captures some of most popular DevOps tools with brief explanation shown in the below image, such as:

1) Puppet

It is the most widely used DevOps tool that allows the delivery and release of the technology changes quickly and frequently. It includes features of versioning, automated testing, and continuous delivery. It also enables to manage entire infrastructure as code without expanding the size of the team.

2) Ansible

It is one of the leading open-source IT engine that automates application deployment, cloud provisioning, intra service orchestration, and other IT tools. It enables team to scale automation and speed up productivity.

Some of the features are:

• It is easy to use to open source deploy applications.
• It helps in avoiding complexity in the software development process.
• It eliminates repetitive tasks.
• It manages complex deployments and speeds up the development process.

3) Docker

Docker is one of the most popular DevOps tool that allows building, ship, and run distributed applications on multiple systems.

Features

• It configures the system more comfortable and faster.
• It increases productivity.
• It provides containers that are used to run the application in an isolated environment.
• It routes the incoming request for published ports on available nodes to an active container. 
• It allows saving secrets into the swarm itself.

4) Nagios

Nagios one of the powerful DevOps tools that is used to determine the errors and enable its rectification with the help of network, infrastructure, server, and log monitoring systems.

Features

• It provides complete monitoring of desktop and server operating systems.
• The network analyzer helps to identify bottlenecks and optimize bandwidth utilization.
• It helps to monitor components such as services, application, OS, and network protocol.
• It also provides to complete monitoring of Java Management Extensions.

5) CHEF

A chef is a  cloud based tool for achieving scale, speed, and consistency.

Features

• It maintains high availability.
• It can manage multiple cloud environments.
• Ruby language is used to create a domain-specific language.
• The chef does not make any assumptions about the current status of the node.

6) Jenkins

Jenkins is one of the important software that allows continuous integration. It is installed on a server where the application build is planned.

Features

• Jenkins increases the scale of automation.
• It can easily set up and configure via a web interface.
• It can distribute the tasks across multiple machines, thereby increasing concurrency.
• It supports continuous integration and continuous delivery.
• It offers 400 plugins to support the building and testing any project virtually.
• It requires little maintenance and has a built-in GUI tool for easy updates.

7) Git

Git is widely used open-source distributed version control system. It is very common as it is freely available for everyone. It is capable enough to handle minor to major projects with speed and efficiency. The version control helps in maintainability of the code. 

Features

• It is a free open source tool.
• It allows distributed development.
• It supports the pull request.
• It enables a faster release cycle.
• Git is very scalable.
• It is very secure and completes the tasks very fast.

8) Splunk

Splunk is one of the widely used monitoring tool that makes machine data usable, accessible, and valuable to everyone. It delivers operational intelligence to DevOps teams. 

Features

• It has the next-generation monitoring and analytics solution.
• It delivers a single, unified view of different IT services.
• Extend the Splunk platform with purpose-built solutions for security.
• Data drive analytics with actionable insight.

9) Selenium

Selenium is a popular software testing framework for web applications that provides an user friendly interface for developing automated tests.

Features

• It is a free open source tool.
• It supports multiplatform for testing, such as Android and ios.
• It is easy to build a keyword-driven framework for a WebDriver.
• It creates robust browser-based regression automation suites and tests.