1- GIT

Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency.

Git is easy to learn and has a tiny footprint with lightning fast performance. It outclasses SCM tools like Subversion, CVS, Perforce, and ClearCase with features like cheap local branching, convenient staging areas, and multiple workflows.

To integrate Git with your DevOps workflow, you also need to host repositories where your team members can push their work. Currently, the two best online Git repo hosting services are GitHub and Bitbucket. 

2-Jenkins

It’s an open source CI/CD server that allows you to automate the different stages of your delivery pipeline.
The leading open source automation server, Jenkins provides hundreds of plugins to support building, deploying and automating any project.

It offers more than 1,000 plugins, so it integrates with almost all DevOps tools, from Docker to Puppet.

3- Docker

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Docker is a tool designed to make it easier to create, deploy, and run applications by using containers. Containers allow a developer to package up an application with all of the parts it needs, such as libraries and other dependencies, and ship it all out as one package.

In a way, Docker is a bit like a virtual machine. But unlike a virtual machine, rather than creating a whole virtual operating system, Docker allows applications to use the same Linux kernel as the system that they’re running on and only requires applications be shipped with things not already running on the host computer.

4-Kubernetes

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Kubernetes is an open-source container orchestration system for automating application deployment, scaling, and management.^[ It was originally designed by Google, and is now maintained by the Cloud Native Computing Foundation.

It aims to provide a “platform for automating deployment, scaling, and operations of application containers across clusters of hosts”. It works with a range of container tools, including Docker.

Many cloud services offer a Kubernetes-based platform or infrastructure as a service (PaaS or IaaS) on which Kubernetes can be deployed as a platform-providing service. Many vendors also provide their own branded Kubernetes distributions.

5- Chef

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Chef is a configuration management tool for dealing with machine setup on physical servers, virtual machines and in the cloud. Configuration management is all about trying to ensure that the files and software you are expecting to be on a machine are present, configured correctly, and working as intended.

When you have only a single machine this is fairly simple. When you have five or ten servers, it is still possible to do this manually, but it may take all day. However, when your infrastructure scales up into the thousands we need a better way of doing things. Chef helps solve this problem by treating infrastructure as code. Rather than manually changing anything, the machine setup is described in a Chef recipe.

Collections of recipes are stored in a cookbook. One cookbook should relate to a single task, but can have a number of different server configurations involved (for example a web application with a database, will have two recipes, one for each part, stored together in a cookbook). There is a Chef server which stores each of these cookbooks and as a new chef client node checks in with the server, recipes are sent to tell the node how to configure itself.

6- Nagios

Nagios is a free and open source computer-software application that monitors systems, networks and infrastructure. Nagios offers monitoring and alerting services for servers, switches, applications and services. It alerts users when things go wrong and alerts them a second time when the problem has been resolved.

Although there are many DevOps tools for infrastructure monitoring, Nagios stands out due to its rich plugin ecosystem.