Backups

• Attic - A deduplicating backup program written in Python.
• Bareos - A fork of Bacula backup tool.
• Barman - Backup and Recovery Manager for disaster recovery of PostgreSQL servers.
• Backupninja - Lightweight, extensible meta-backup system.
• Backuppc - Client-server model backup tool with file pooling scheme.
• Brebis - A fully automated backup checker.
• Duplicity - Encrypted bandwidth-efficient backup using the rsync algorithm.
• Snebu - client deduplication and transparent compression.
• UrBackup - Another client-server backup system.
• ZBackup - A versatile deduplicating backup tool.
• SafeKeep - Centralized pull-based backup using rdiff-backup.
• Bup - Incremental backups with rolling checksums, git packfiles, de-duplication, and a FUSE filesystem.
• Duplicity - Encrypted bandwidth-efficient backup using the rsync algorithm.
• restic - Fast, secure, efficient backup program
• ZBackup - A versatile deduplicating backup tool.
• Backup - Provides an elegant DSL in Ruby for performing backups on UNIX-like systems.
• DREBS - AWS EBS backup script that supports strategies.
• Brebis - A fully automated backup checker.
• Backuppc - Client-server model backup tool with file pooling scheme.
• Snebu - client deduplication and transparent compression.
• SafeKeep - Centralized pull-based backup using rdiff-backup.
• Bacula - Another Client-server model backup tool.
• Lsyncd - File Monitor which spawns a process to synchronize the changes (rsync by default).
• Attic - A deduplicating backup program written in Python.
• Bareos - A fork of Bacula backup tool.

Blogs

• Code as Craft - Etsy's Ops blog, lots of technical posts.
• DevOpsGuys - Devops consultants who blog about operations.
• Code as Craft - Etsy's Ops blog, lots of technical posts.
• Rackspace Developers - Slightly biased blog with lots of Devops Topics.

Books

• The Linux Command Line - A book about the Linux command line by William Shotts.
• The Phoenix Project: A Novel about IT, DevOps, and Helping Your Business Win - How DevOps techniques can fix the problems that happen in IT organizations.
• The Practice of System and Network Administration - The first and second editions describes the best practices of system and network administration, independent of specific platforms or technologies.
• UNIX and Linux System Administration Handbook - Approaches system administration from a practical perspective.
• The Visible Ops Handbook: Implementing ITIL in 4 Practical and Auditable Steps - Is a methodology designed to jumpstart implementation of controls and process improvement.
• The Phoenix Project: A Novel about IT, DevOps, and Helping Your Business Win - How DevOps techniques can fix the problems that happen in IT organizations.

Build Automation

• Apache Ant - Automation build tool, similar to make, written in Java.
• GNU Make - The most popular automation build tool for many purposes.

ChatOps

• Err - A plugin based chatbot designed to be easily deployable, extensible and maintainable.
• Hubot - A customizable, life embetterment robot.
• Lita - A robot companion for your company's chat room.
• CloudBot - The simple, fast, expandable, open-source Python IRC bot.
• Lazlo - A chatops automation framework in Go.
• Eggdrop - The world's most popular Open Source IRC bot, designed for flexibility and ease of use.
• KeyBase - Encrypted chat, cloud and git.

Cloning

• Clonezilla - Partition and disk imaging/cloning program.
• Fog - Another computer cloning solution.
• Redo Backup - Easy Backup, Recovery and Restore.
• Redo Backup - Easy Backup, Recovery and Restore.
• Clonezilla - Partition and disk imaging/cloning program.

Cloud Computing

• Eucalyptus - Open source private cloud software with AWS compatibility.
• OpenStack - Open source software for building private and public clouds.
• The Foreman - Foreman is a complete lifecycle management tool for physical and virtual servers. FOSS.
• Archipel - Manage and supervise virtual machines using Libvirt.
• AppScale - Open source cloud software with Google App Engine compatibility.
• Tsuru - Tsuru is an extensible and open source Platform as a Service software.
• Terraform - Terraform allows you to practice infrastructure as code and is commonly used for AWS/GCE.

Cloud Orchestration

• BOSH - IaaS orchestration platform originally written for deploying and managing Cloud Foundry PaaS, but also useful for general purpose distributed systems.
• MCollective - Ruby framework to manage server orchestration, developed by Puppet labs.
• StackStorm - Event Driven Operations and ChatOps platform for infrastructure management. Written in Python.
• doozerd - Doozer is a highly-available, completely consistent store for small amounts of extremely important data.
• etcd - A highly-available key value store for shared configuration and service discovery.
• Overcast - Deploy VMs across different cloud providers, and run commands and scripts across any or all of them in parallel via SSH.
• BOSH - IaaS orchestration platform originally written for deploying and managing Cloud Foundry PaaS, but also useful for general purpose distributed systems.
• serf - Serf is a tool for cluster membership.
• consul - It is a tool for discovering and configuring services in your infrastructure.
• Juju - Cloud orchestration tool which manages services as charms, YAML configuration and deployment script bundles.
• MCollective - Ruby framework to manage server orchestration, developed by Puppet labs.
• Cloudify - Open source TOSCA-based cloud orchestration software platform written in Python and YAML.

Cloud Storage

• git-annex assistant - A synchronised folder on each of your OSX and Linux computers, Android devices, removable drives, NAS appliances, and cloud services.
• nextCloud - Provides access to your files via the web
• Swift - A highly available, distributed, eventually consistent object/blob store.
• ownCloud - Provides universal access to your files via the web, your computer or your mobile devices.
• git-annex assistant - A synchronised folder on each of your OSX and Linux computers, Android devices, removable drives, NAS appliances, and cloud services.

Code Review

• Gerrit - Based on the Git version control, it facilitates software developers to review modifications to the source code and approve or reject those changes.
• Review Board - Web-based collaborative code review tool.
• Gerrit - Based on the Git version control, it facilitates software developers to review modifications to the source code and approve or reject those changes.
• Gerrit - Based on the Git version control, it facilitates software developers to review modifications to the source code and approve or reject those changes.
• Phabricator - Code review tool build by facebook and used by WikiMedia, FB, dropbox etc. Comes with an integrated wiki, bug tracker, VC integration and a CLI tool called arcanist.

Collaborative Software

• EGroupware - Groupware software written in PHP.
• Horde Groupware - PHP based collaborative software suite that includes email, calendars, wikis, time tracking and file management.
• SOGo - Collaborative software server with a focus on simplicity and scalability.
• Citadel/UX - Collaboration suite (messaging and groupware) that is descended from the Citadel family of programs.
• EGroupware - Groupware software written in PHP.
• Horde Groupware - PHP based collaborative software suite that includes email, calendars, wikis, time tracking and file management.
• Kolab - Another groupware suite.

Configuration Management

• Salt - It's written in Python.
• (R)?ex - It's written in Perl and use plain Perl, over SSH without agent.
• Slaughter - It's written in Perl.
• mgmt - Next generation config management written in Go.
• Pallet - Infrastructure definition, configuration and management via a Clojure DSL.
• Puppet - It's written in Ruby and uses Puppet's declarative language or a Ruby DSL.

Configuration Management Database

• Clusto - Helps you keep track of your inventory, where it is, how it's connected, and provides an abstracted interface for interacting with the elements of the infrastructure.
• Collins - At Tumblr, it's the infrastructure source of truth and knowledge.
• Ralph - Asset management, DCIM and CMDB system for large Data Centers as well as smaller LAN networks.
• Sicekit - The systems & infrastructure encyclopaedia toolkit (based on MediaWiki).

Continuous Integration & Continuous Deployment

• Concourse CI - A pipeline-based CI system written in Go.
• TeamCity - Powerful Continuous Integration out of the box
• GitLab CI - Based off of ruby. They also provide GitLab, which manages git repositories.
• Go - Open source continuous delivery server.
• Drone - Continuous integration server built on Docker and configured using YAML files.
• Buildbot - Python-based toolkit for continuous integration.
• Jenkins - An extendable open source continuous integration server.

Control Panels

• Feathur - VPS Provisioning and Management Software.
• Froxlor - Easy to use panel for Linux with Nginx and PHP-FPM support.
• ISPConfig - Hosting control panel for Linux.
• ZPanel - Control panel for Linux, BSD, and Windows.
• Virtualmin - Control panel for Linux based on webmin.
• VestaCP - Hosting panel for Linux but with Nginx.
• ZPanel - Control panel for Linux, BSD, and Windows.
• Ajenti - Control panel for Linux and BSD.
• Webmin - Linux server control panel.
• Sentora - Control panel for Linux, BSD, and Windows based on ZPanel.
• ISPConfig - Hosting control panel for Linux.

Deployment Automation

• Mina - Really fast deployer and server automation tool (rake based).
• Rocketeer - PHP task runner and deployment tool.
• Vlad the Deployer - Deployment automation (rake based).
• Mina - Really fast deployer and server automation tool (rake based).
• Fabric - Python library and cli tool for streamlining the use of SSH for application deployment or systems administration tasks.

Diagramming

• drawthe.net - Draws network diagrams dynamically from a text file describing the placement, layout and icons.
• drawthe.net - Draws network diagrams dynamically from a text file describing the placement, layout and icons.

Distributed Filesystems

• Ceph - Distributed object store and file system.
• DRBD - Distributed Replicated Block Device.
• MogileFS - Application level, network distributed file system.
• OpenAFS - Distributed network file system with read-only replicas and multi-OS support.
• TahoeLAFS - secure, decentralized, fault-tolerant, peer-to-peer distributed data store and distributed file system.
• MogileFS - Application level, network distributed file system.
• LeoFS - Unstructured object/data storage and a highly available, distributed, eventually consistent storage system.
• Lustre - A type of parallel distributed file system, generally used for large-scale cluster computing.
• MogileFS - Application level, network distributed file system.
• DRBD - Distributed Replicated Block Device.
• MooseFS - Fault tolerant, network distributed file system.

DNS

• Bind - The most widely used name server software.
• djbdns - A collection of DNS applications, including tinydns.
• Designate - DNS REST API that support several DNS servers as its backend.
• dnsmasq - A lightweight service providing DNS, DHCP and TFTP services to small-scale networks.
• Knot - High performance authoritative-only DNS server.
• NSD - Authoritative only, high performance, simple name server.
• PowerDNS - DNS server with a variety of data storage back-ends and load balancing features.
• Yadifa - Lightweight authoritative Name Server with DNSSEC capabilities powering the .eu top-level domain.
• dnsmasq - A lightweight service providing DNS, DHCP and TFTP services to small-scale networks.
• Bind - The most widely used name server software.

Editors

• GNU Emacs - An extensible, customizable text editor-and more.
• Haroopad - Markdown editor with live preview.
• ICEcoder - Code editor awesomeness, built with common web languages.
• Lime - Aims to provide an open source solution to Sublime Text
• SciTE - A SCIntilla based Text Editor.
• Nano - A popular text editor, by default comes with most Linux distributions.
• Visual Studio Code - Fast, hackable, multi-platform code editor from Microsoft.
• Haroopad - Markdown editor with live preview.
• IntellijIDEA - Capable and ergonomic IDE, written in Java, It has a lot of plug-ins.
• jotgit - Git-backed real-time collaborative code editing.

IT Asset Management

• RackTables - Datacenter and server room asset management like document hardware assets, network addresses, space in racks, networks configuration.
• OpenDCIM - A web based Data Center Infrastructure Management application.
• Netbox - IP address management (IPAM) and data center infrastructure management (DCIM) tool.
• RackTables - Datacenter and server room asset management like document hardware assets, network addresses, space in racks, networks configuration.
• GLPI - Information Resource-Manager with an additional Administration Interface.
• OpenDCIM - A web based Data Center Infrastructure Management application.

LDAP

• 389 Directory Server - Developed by Red Hat.
• Apache Directory Server - Apache Software Foundation project written in Java.
• Fusion Directory - Improve the Management of the services and the company directory based on OpenLDAP.
• OpenDJ - Fork of OpenDS.
• OpenDS - Another directory server written in Java.
• OpenLDAP - Developed by the OpenLDAP Project.
• Apache Directory Studio - The Eclipse-based LDAP browser and directory client
• 389 Directory Server - Developed by Red Hat.
• Fusion Directory - Improve the Management of the services and the company directory based on OpenLDAP.

Log Management

• Flume - Distributed log collection and aggregation system.
• Heka - Stream processing system which may be used for log aggregation.
• Octopussy - Log Management Solution (Visualize / Alert / Report).
• Graylog2 - Pluggable Log and Event Analysis Server with Alerting options.
• Logstash - Tool for managing events and logs.
• Heka - Stream processing system which may be used for log aggregation.

Mail Servers

• Courier IMAP/POP3 - Fast, scalable, enterprise IMAP and POP3 server.
• Cyrus IMAP/POP3 - Intended to be run on sealed servers, where normal users are not permitted to log in.
• Dovecot - IMAP and POP3 server written primarily with security in mind.
• Qpopper - One of the oldest and most popular server implementations of POP3.
• Exim - Message transfer agent (MTA) developed at the University of Cambridge.
• Haraka - A high-performance, pluginable SMTP server written in JavaScript.
• OpenSMTPD - Secure SMTP server implementation from the OpenBSD project.
• Postfix - Fast, easy to administer, and secure Sendmail replacement.
• Qmail - Secure Sendmail replacement.
• Sendmail - Message transfer agent (MTA).
• Mail-in-a-Box - Take back control of your email with this easy-to-deploy mail server in a box.
• Maildrop - Open Source disposable email SMTP server, also useful for development.
• Qpopper - One of the oldest and most popular server implementations of POP3.

Messaging

• Metronome IM - Fork of Prosody IM.
• Openfire - Real time collaboration (RTC) server.
• Prosody IM - XMPP server written in Lua.
• Tigase - XMPP server implementation in Java.
• Kaiwa - Web based chat client in the style of common paid alternatives.
• Kaiwa - Web based chat client in the style of common paid alternatives.
• Candy - Multi user XMPP client written in Javascript.
• Lets-Chat - A self hosted chat suite written in Node.
• ejabberd - XMPP instant messaging server written in Erlang/OTP.

Metric & Metric Collection

• Collectl - High precision system performance metrics collecting tool.
• ~~dashing~~ - No Longer Maintained - Ruby gem that allows for rapid statistical dashboard development. An all HTML5 approach allows for big screen displays in data centers or conference rooms.
• Ganglia - High performance, scalable RRD based monitoring for grids and/or clusters of servers. Compatible with Graphite using a single collection process.
• Graphite - Open source scalable graphing server.
• KairosDB - Fast distributed scalable time series database, fork of OpenTSDB 1.x.