
DevOps & Co

GitHub is a web-based hosting service for projects that use the Git revision control system. It is written in Ruby on Rails by Logical Awesome developers Chris Wanstrath, PJ Hyett, and Tom Preston-Werner. GitHub offers both commercial plans and free accounts for open source projects.
The site provides social networking functionality like feeds, followers and the network graph to display how developers work on their versions of a repository.
GitHub also operates a pastebin-style site at gist.github.com, wikis for the individual repositories and web pages that can be edited through a git repository.
GitHub has a built-in, highly functional Issue Tracker.
GitLab is a on-premise or hosted Git repository management tool. It also includes code reviews, issue tracking, wikis, and continuous integration.
Jenkins is a fork of Hudson and is a continuous build system for software projects.
The leading open source automation server, Jenkins provides hundreds of plugins to support building, deploying and automating any project.
Jenkins is an application that monitors executions of repeated jobs, such as building a software project or jobs run by cron. Among those things, current Jenkins focuses on the following two jobs:
Building/testing software projects continuously, just like CruiseControl or DamageControl. In a nutshell, Jenkins provides an easy-to-use so-called continuous integration system, making it easier for developers to integrate changes to the project, and making it easier for users to obtain a fresh build. The automated, continuous build increases the productivity. Monitoring executions of externally-run jobs, such as cron jobs and procmail jobs, even those that are run on a remote machine. For example, with cron, all you receive is regular e-mails that capture the output, and it is up to you to look at them diligently and notice when it broke. Jenkins keeps those outputs and makes it easy for you to notice when something is wrong.
Configuration files describe to Terraform the components needed to run a single application or your entire datacenter. Terraform generates an execution plan describing what it will do to reach the desired state, and then executes it to build the described infrastructure. As the configuration changes, Terraform is able to determine what changed and create incremental execution plans which can be applied.
The infrastructure Terraform can manage includes low-level components such as compute instances, storage, and networking, as well as high-level components such as DNS entries, SaaS features, etc.
Ansible is a radically simple IT automation engine that automates cloud provisioning, configuration management, application deployment, intra-service orchestration, and many other IT needs.
Being designed for multi-tier deployments since day one, Ansible models your IT infrastructure by describing how all of your systems inter-relate, rather than just managing one system at a time.
It uses no agents and no additional custom security infrastructure, so it’s easy to deploy — and most importantly, it uses a very simple language (YAML, in the form of Ansible Playbooks) that allow you to describe your automation jobs in a way that approaches plain English.