This is the awesome list with all open source and free applications that you can use in your management.
loud Computing
IaaS
Cracow Cloud One (Opensource) The CC1 system provides a complete solution for Private Cloud Computing.
CloudOver (Opensource) CloudOver project is a cloud computing challenge to create simple and scalable open source platform for IaaS cloud environments.
CloudStack (Opensource) Apache CloudStack is open source software designed to deploy and manage large networks of virtual machines, as a highly available, highly scalable Infrastructure as a Service (IaaS) cloud computing platform.
Danube Cloud (Opensource) Datacenter delivered.
Eucalyptus (Opensource) Eucalyptus is open source software for building Amazon Web Services-compatible private and hybrid clouds.
OpenNebula (Opensource) Simple yet Powerful Turnkey Solution to Build Clouds and Manage Data Center Virtualization.
Openstack (Opensource) OpenStack controls large pools of compute, storage, and networking resources throughout a datacenter, managed through a dashboard or via the OpenStack API.
Proxmox VE (Opensource) A complete open source server virtualization management software based on KVM and container-based virtualization and manages virtual machines, Linux containers, storage, virtualized networks, and HA clusters.
Synnefo (Opensource) Synnefo is open source cloud software, used to create massively scalable IaaS clouds.
Wakame (Opensource) Wakame-vdc is an IaaS cloud computing framework. Basically you can set it up and offer server infrastructure “up in the cloud”. Users can control Wakame-vdc through a web browser.
ZStack (Opensource) ZStack is open source IaaS software aiming to automate datacenters, managing resources of compute, storage, and networking all by APIs.
PaaS
Apache Stratos (Opensource) Highly-extensible PaaS framework that helps run Apache Tomcat, PHP, and MySQL applications and can be extended to support many more environments on all major cloud infrastructures.
Atlantis (Opensource) Atlantis is an Open Source PaaS for HTTP applications built on Docker and written in Go. It makes it easy to build and deploy applications in a safe, repeatable fashion, and flexibly route requests to the appropriate containers.
Cloud Foundry (Opensource) Cloud Foundry provides deep and varied products and services as a platform as a service.
Cloudify (Opensource) Pure-Play Open Source Cloud Orchestration.
Cloudron (Opensource) Effortlessly Self-Host Web Apps. Cloudron is a platform to run apps on your server.
Convox (Opensource) Build, deploy, and manage applications with ease.
Deis (Opensource) Your PaaS. Your Rules. Open Source Application Platform For Public and Private Clouds.
Dokku (Opensource) A docker-powered mini-Heroku PaaS that helps you build and manage the lifecycle of applications. The smallest PaaS implementation you’ve ever seen.
Flynn (Opensource) Flynn deploys apps, scales apps, and manages databases with best practices right out of the box. Automatically doing all the things that were too complicated, expensive, or time consuming to do manually.
Helion Stackato (Free) HPE’s Cloud Foundry Foundation-certified PaaS solution, and leads efforts to advance open standards, higher quality, and interchangeability among industry vendors.
Kel (Opensource) An open-source, Kubernetes-based PaaS built in Python and Go.
Last.Backend (Opensource) OLast.Backend is an open-source platform, which allows you build a personal cloud on your servers based on kubernetes technology.
Openshift Origin (Opensource) OpenShift 3, build, deploy, and manage your applications with Docker and Kubernetes.
Puffin (Opensource) Lightweight webapp catalog based on containers, with user interface à la mobile app store.
SlipStream (Opensource) SlipStream open source PaaS, App Store and DevOps engine.
Tsuru (Opensource) Tsuru is an extensible and open source Platform as a Service software.
CaaS/FaaS
AMP (Opensource) An open source CaaS for Docker, batteries included.
Apache OpenWhisk (Opensource) A serverless, open source cloud platform that executes functions in response to events at any scale.
ATOMIQ (Opensource) The open source unified CaaS / FaaS platform for Docker, batteries included.
Fission (Opensource) Fission is a framework for serverless functions on Kubernetes.
IronFunctions (Opensource) IronFunctions is an open source serverless computing platform for any cloud – private, public, or hybrid.
OpenFaaS (Opensource) Serverless Functions Made Simple.
OpenLambda (Opensource) An Apache-licensed serverless computing project, written in Go and based on Linux containers.
Continuous Integration and Continuous Deployment
Abstruse (Opensource) A Continuous Integration platform requiring zero or minimal configuration to get started, providing safe testing and deployment environment using Docker containers.
Buildbot (Opensource) Buildbot is an open-source framework for automating software build, test, and release processes.
Concourse (Opensource) Concourse is a pipeline-based CI system written in Go.
CruiseControl (Opensource) CruiseControl is both a continuous integration tool and an extensible framework for creating a custom continuous build process.
Deployer (Opensource) Deployment tool for PHP.
Drone (Opensource) Drone is a Continuous Delivery platform built on Docker, written in Go.
Gitploy (Opensource) Build the deployment system around GitHub in minutes.
Gitlab CI (Opensource) GitLab has integrated CI and CD to test, build and deploy your code.
GO CD (Opensource) Automate and streamline your build-test-release cycle for reliable, continuous delivery of your product.
Integrity (Opensource) Continuous Integration server.
Jenkins (Opensource) Jenkins provides hundreds of plugins to support building, deploying and automating any project.
PHPCI (Opensource) PHPCI is a free and open source continuous integration tool specifically designed for PHP.
Strider (Opensource) Open Source Continuous Integration & Deployment Server.
TeamCity (Free) Powerful Continuous Integration out of the box.
Desktop utilities
Windows
AxCrypt (Opensource) AxCrypt is the leading open source file encryption software for Windows. It integrates seamlessly with Windows to compress, encrypt, decrypt, store, send and work with individual files.
CrystalDiskInfo (Opensource) A HDD/SSD utility software which supports S.M.A.R.T. and a part of USB-HDD.
CurrPorts (Free) CurrPorts is network monitoring software that displays the list of all currently opened TCP/IP and UDP ports on your local computer.
RapidCRC Unicode (Opensource) Windows tool to quickly create and verify hash checksums.
Rufus (Opensource) The Reliable USB Formatting Utility.
Linux
Mac
All (yeah!)
Camunda (Opensource) Camunda is an open source platform for workflow and business process management.
Etcher (Opensource) Burn images to SD cards & USB drives, safe & easy.
Insomnia (Free) A simple, beautiful, and free REST API client.
OWASP ZAP (Opensource) The OWASP Zed Attack Proxy (ZAP) is an easy to use integrated penetration testing tool for finding vulnerabilities in web applications.
Synergy (Opensource) Synergy combines your desktop devices together in to one cohesive experience. It’s software for sharing your mouse and keyboard between multiple computers on your desk. It works on Windows, Mac OS X and Linux.
Firewall, Gateway and appliances
BrazilFW (Free) Mini Linux distribution designed to be used as a Firewall and Router that runs easily on older computers.
ClearOS Community (Free) Linux distribuiton designed for use in small and medium enterprises as a network gateway and network server with a web-based administration interface.
Endian (Free) Linux based product designed for home that can transform any unused hardware appliance into a full-featured Unified Threat Management solution and to make security simple and help protect home networks by using the power of Opensource.
IPCop (Free) The IPCop Firewall is a Linux firewall distribution. It is geared towards home and SOHO users. The IPCop web-interface is very user-friendly and makes usage easy.
IPFire (Opensource) The Open Source Firewall Distribution.
NethServer (Opensource) NethServer is an operating system for Linux enthusiasts, designed for small offices and medium enterprises.
OPNsense (Opensource) OPNsense is an open source, easy-to-use and easy-to-build FreeBSD based firewall and routing platform.
pfSense (Opensource) The pfSense project is a free network firewall distribution, based on the FreeBSD operating system with a custom kernel and including third party free software packages for additional functionality.
Smoothwall (Free) Free firewall that includes its own security-hardened GNU/Linux operating system and an easy-to-use web interface.
Sophos UTM Home Edition (Free) Sophos UTM is easy to use, thanks to the configurable real-time dashboard, flexible modular licensing, and intuitive reusable network object definitions.
Untangle NG Firewall (Free) NG Firewall manages every aspect of network control from content filtering to web caching, remote access to policy enforcement, all in one simple, drag & drop interface.
VyOS (Opensource) VyOS is a community fork of Vyatta, a Linux-based network operating system that provides software-based network routing, firewall, and VPN functionality.
Zentyal Server (Opensource, Forum) The on-premise Mail and Directory server.
Server
hMailServer (Opensource) Opensource mail server for Microsoft Windows.
MTA
Client
N1 (Opensource) An extensible mail client built on the modern web.
Webclient
AfterLogic WebMail Lite (Opensource, Demo) Fast and easy-to-use webmail front-end for your existing IMAP mail server, Plesk or cPanel.
Cypht (Opensource) All your E-mail, from all your accounts, in one place. Cypht is like a news reader, but for E-mail. Cypht does not replace your existing accounts – it combines them into one. And it’s also a news reader :).
Mailpile (Opensource) Mailpile is an effort to reclaim private communication on the Internet. A project to rescue our personal lives from the proprietary cloud and prevent our conversations from being strip-mined for corporate profit and government surveillance.
ProtonMail WebClient (Opensource) Official AngularJS Web Client for ProtonMail.
RainLoop (Opensource, Demo) Simple, modern & fast web-based email client.
Roundcube (Opensource, Demo) A browser-based multilingual IMAP client with an application-like user interface.
SquirrelMail (Opensource, Demo) Standards-based webmail package written in PHP. It includes built-in pure PHP support for the IMAP and SMTP protocols, and all pages render in pure HTML 4.0 (with no JavaScript required) for maximum compatibility across browsers.
All-in-one
Axigen (Free, Demo) The Axigen Free Mail Server is a great alternative to open source. It is a turnkey messaging solution, perfect for small & micro businesses, integration projects or test environments.
Citadel (Opensource) Easy, versatile, and powerful, thanks to its exclusive “rooms” based architecture.
iRedMail (Opensource) A zero cost, fully fledged, full-featured mail server solution.
Kolab (Opensource) The world’s most loved open source collaboration software.
Mailcow (Opensource) Mailserver suite based on Dovecot, Postfix and other open source software, that provides a modern Web UI for administration. In future versions mailcow will provide Cal- and CardDAV support.
Mail-in-a-Box (Opensource) Mail-in-a-Box lets you become your own mail service provider in a few easy steps. It’s sort of like making your own gmail, but one you control from top to bottom.
Modoboa (Opensource, Demo) Mail hosting and management platform including a modern and simplified Web User Interface. It provides useful components such as an administration panel or a webmail.
PEPS (Opensource) Open source Email + File sharing with end-to-end encryption.
Poste (Free, Demo) Complete mail server built in docker.
SOGo (Opensource) Share your calendars, address books and mails in your community with a completely free and open source solution.
Zimbra (Opensource) Zimbra Collaboration Open Source Edition provides administrators and their end users innovative features that solve the challenges faced by organizations using today’s legacy communications infrastructure.
Gateway
CipherMail (Free) Centrally managed email encryption at the gateway level and on mobile devices.
Scrollout F1 (Free) An easy to use, already adjusted email gateway (firewall) offering free anti-spam, anti-virus protection in order to secure all existing email servers, such as Microsoft Exchange, Lotus Domino, Postfix, Exim, Qmail and more.
MailCleaner (Free) MailCleaner is a full email filtering gateway. It includes a complete GNU/Linux OS and a graphical web interface for user and administrative access.
Xeams (Free) Free email server that can be used by any corporation to handle their enterprise email. It works on any operating system and can handle unlimited number of emails and domains. Xeams can work in 3 modes, Stand alone, Spam firewall or Hybrid mode.
Tools
ViMbAdmin (Opensource) The ViMbAdmin provides a web based virtual mailbox administration system allowing mail administrators to manage domains, mailboxes and aliases.
Version Control System “VCS”
VCS
Bazaar (Opensource) Distributed VCS that enables easy collaborative development. One of Bazaar’s strengths is its adaptibility to different work flows, centralized, distributed or anything in between.
BitKeeper (Opensource) BitKeeper is a fast, enterprise-ready, distributed SCM that scales up to very large projects and down to tiny ones.
CVS (Opensource) Concurrent Versions System is a version control system, an important component of Source Configuration Management (SCM). Using it, you can record the history of sources files, and documents.
Darcs (Opensource) Free and open source, cross-platform version control system, like git, mercurial or svn but with a very different approach: focus on changes rather than snapshots.
Fossil (Opensource) Simple, high-reliability, distributed software configuration management system with these advanced features, Integrated Bug Tracking, Wiki, and Technotes, Built-in Web Interface, Self-Contained, Autosync and more.
Git (Opensource) Free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency.
Mercurial (Opensource) Mercurial is a free, distributed source control management tool. It efficiently handles projects of any size and offers an easy and intuitive interface.
Subversion (Opensource) Open-source, centralized version control system characterized by its reliability as a safe haven for valuable data.
Client
NaughtySVN (Opensource) A Nautilus extension for Subversion.
PagaVCS (Opensource) PagaVCS is a Nautilus, Thunar and mugCommander integrated TortoiseSVN clone, Subversion GUI client for Linux desktop.
RabbitVCS (Opensource) RabbitVCS is a set of graphical tools written to provide simple and straightforward access to the version control systems you use.
TortoiseGit (Opensource) TortoiseGit provides overlay icons showing the file status, a powerful context menu for Git and much more!
TortoiseSVN (Opensource) An Apache SVN client, implemented as a Windows shell extension.
Server
Bonobo Git Server (Opensource) Set up your own self hosted git server on IIS for Windows. Manage users and have full control over your repositories with a nice user friendly graphical interface.
Gitblit (Opensource) Gitblit is an open-source, pure Java stack for managing, viewing, and serving Git repositories.
GitBucket (Opensource, Demo) A Git platform powered by Scala with easy installation, high extensibility & github API compatibility.
Gitea (Opensource) Gitea: Git with a cup of tea.
Gitlab Community (Opensource, Demo) Web-based Git repository manager with wiki and issue tracking features.
Gitolite (Opensource) Gitolite allows you to setup git hosting on a central server, with very fine-grained access control and many (many!) more powerful features.
gitprep (Opensource, Demo) Portable GitHub system into your own server.
Gogs (Opensource, Demo) Gogs (Go Git Service) is a painless self-hosted Git service.
Kallithea (Opensource, Demo) Free Software source code management system that supports two leading version control systems, Mercurial and Git, and has a web interface that is easy to use for users and admins.
Pagure (Opensource, Demo) You can host your project, let your users report issues or request enhancements using the ticketing system and build your community of contributors allowing them to fork your projects and contribute to it via the now-popular pull-request mechanism.
RhodeCode Community (Opensource, Demo) On-premise Source Code Management for Mercurial, Git & Subversion.
SCM Manager (Opensource) The easiest way to share and manage your Git, Mercurial and Subversion repositories over http.
Sourcegraph (Free) Sourcegraph is the smarter code host powering top-tier development teams.
VisualSVN Server (Free) VisualSVN Server makes the Subversion server easy and convenient to install and administer on Windows.
Tools
cgit (Opensource) A hyperfast web frontend for git repositories written in C.
iF.SVNAdmin (Opensource) Web-based GUI to manage Subversion repositories and User/Group permissions (+LDAP support).
Git Cola (Opensource) Git Cola is a sleek and powerful graphical user interface for Git.
GitList (Opensource) An elegant and modern git repository viewer.
GitPHP (Opensource) Web frontend for git repositories. It emulates the look of standard gitweb, but is written in PHP and makes use of Smarty templates for customization..
Git Webui (Opensource) A standalone local web based user interface for git repositories.
Git Web Access (Opensource) Provides an ASP.NET HttpHandler that let you run Smart HTTP Git on IIS.
ViewVC (Opensource) ViewVC is a browser interface for CVS and Subversion version control repositories. It generates templatized HTML to present navigable directory, revision, and change log listings.
WebSVN (Opensource) WebSVN offers a view onto your subversion repositories. You can view the log of any file or directory and see a list of all the files changed, added or deleted in any given revision.