Administration Apps

Backup

Amanda Client-server model backup tool	Attic A deduplicating backup program written in Python	Bacula Another Client-server model backup tool	Bareos A fork of Bacula backup tool	Barman Backup and Recovery Manager for disaster recovery of PostgreSQL servers
Backup Provides an elegant DSL in Ruby for performing backups on UNIX-like systems	Backuppc Client-server model backup tool with file pooling scheme	Brebis A fully automated backup checker	Bup Incremental backups with rolling checksums, git packfiles, de-duplication, and a FUSE filesystem	Burp Network backup and restore program
Duplicati Multiple backends, encryption, web-ui and multi-OS backup tool	Duplicity Encrypted bandwidth-efficient backup using the rsync algorithm	FreeFileSync Folder comparison and synchronization tool	Lsyncd File Monitor which spawns a process to synchronize the changes (rsync by default)	restic Fast, secure, efficient backup program
Rsnapshot Filesystem Snapshotting Utility	SafeKeep Centralized pull-based backup using rdiff-backup	Snebu Snapshot backup with global multi-client deduplication and transparent compression	UrBackup Another client-server backup system	ZBackup A versatile deduplicating backup tool
DREBS AWS EBS backup script that supports strategies

Build Automation

Apache Ant

Automation build tool, similar to make, written in Java

Apache Maven

Build automation tool mainly for Java

GNU Make

Gradle

Another open source build automation system

ChatOps

CloudBot The simple, fast, expandable, open-source Python IRC bot	Eggdrop The world's most popular Open Source IRC bot, designed for flexibility and ease of use	Lita A robot companion for your company's chat room	Hubot A customizable, life embetterment robot	Lazlo A chatops automation framework in Go
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

Cloud Computing

AppScale Open source cloud software with Google App Engine compatibility	Archipel Manage and supervise virtual machines using Libvirt	CloudStack Cloud computing software for creating, managing, and deploying infrastructure cloud services	Cobbler Cobbler is a Linux installation server that allows for rapid setup of network installation environments	Tsuru Tsuru is an extensible and open source Platform as a Service software
Mesos Develop and run resource-efficient distributed systems	OpenNebula An user-driven cloud management platform for sysadmins and devops	Openshift Origin Open source upstream of OpenShift, the next generation application hosting platform developed by Red Hat	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
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	Ansible Contains modules for controlling many types of cloud resources	Cloudify Open source TOSCA-based cloud orchestration software platform written in Python and YAML	consul It is a tool for discovering and configuring services in your infrastructure	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	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	Overcast Deploy VMs across different cloud providers, and run commands and scripts across any or all of them in parallel via SSH	Rundeck Simple orchestration tool
Salt Fast, scalable and flexible systems management software written in Python/ZeroMQ	serf Serf is a tool for cluster membership	StackStorm Event Driven Operations and ChatOps platform for infrastructure management Written in Python	zookeeper ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services

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	ownCloud Provides universal access to your files via the web, your computer or your mobile devices	Seafile Another Open Source Cloud Storage solution	SparkleShare Provides cloud storage and file synchronization services By default, it uses Git as a storage backend
Swift A highly available, distributed, eventually consistent object/blob store	Syncthing Open Source system for private, encrypted and authenticated distribution of data

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

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

Review Board

Web-based collaborative code review tool

Collaborative Software

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	SOGo Collaborative software server with a focus on simplicity and scalability
Zimbra Collaborative software suite, that includes an email server and web client

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	i-doit Open Source IT Documentation and CMDB	iTop Complete open source, ITIL, web based service management tool	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)

Configuration Management

Ansible It's written in Python and manages the nodes over SSH	CFEngine Lightweight agent system Configuration state is specified via a declarative language	Chef It's written in Ruby and Erlang and uses a pure-Ruby DSL	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	(R)?ex It's written in Perl and use plain Perl, over SSH without agent	Salt It's written in Python	Slaughter It's written in Perl

Continuous Integration & Deployment

Buildbot Python-based toolkit for continuous integration	Drone Continuous integration server built on Docker and configured using YAML files	GitLab CI Based off of ruby They also provide GitLab, which manages git repositories	Go Open source continuous delivery server	Jenkins An extendable open source continuous integration server
Spinnaker Open source, multi-cloud continuous delivery platform for releasing software changes	TeamCity Powerful Continuous Integration out of the box

Control Panels

Ajenti Control panel for Linux and BSD	Cockpit New multi-server web interface for Linux servers written in C	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
Sentora Control panel for Linux, BSD, and Windows based on ZPanel	VestaCP Hosting panel for Linux but with Nginx	Virtualmin Control panel for Linux based on webmin	Webmin Linux server control panel	ZPanel Control panel for Linux, BSD, and Windows

Deployment Automation

Capistrano

Deploy your application to any number of machines simultaneously, in sequence or as a rolling set via SSH (rake based)

Fabric

Python library and cli tool for streamlining the use of SSH for application deployment or systems administration tasks

Mina

Really fast deployer and server automation tool (rake based)

Rocketeer

PHP task runner and deployment tool

Vlad the Deployer

Deployment automation (rake based)

Diagramming

drawthenet

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	LeoFS Unstructured object/data storage and a highly available, distributed, eventually consistent storage system	GlusterFS Scale-out network-attached storage file system	HDFS Distributed, scalable, and portable file-system written in Java for the Hadoop framework
Lustre A type of parallel distributed file system, generally used for large-scale cluster computing	MooseFS Fault tolerant, network distributed file system	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
XtreemFS XtreemFS is a fault-tolerant distributed file system for all storage needs

DNS Servers

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	Unbound Validating, recursive, and caching DNS resolver	Yadifa Lightweight authoritative Name Server with DNSSEC capabilities powering the eu top-level domain

Editors

Atom A hackable text editor from GitHub	Brackets Open source code editor for web designers and front-end developers	Eclipse IDE written in Java with an extensible plug-in system	Geany GTK2 text editor	GNU Emacs An extensible, customizable text editor-and more
Haroopad Markdown editor with live preview	ICEcoder Code editor awesomeness, built with common web languages	IntellijIDEA Capable and ergonomic IDE, written in Java, It has a lot of plug-ins	jotgit Git-backed real-time collaborative code editing	Light Table The next generation code editor
Lime Aims to provide an open source solution to Sublime Text	SciTE A SCIntilla based Text Editor	TextMate A graphical text editor for OS X	Vim A highly configurable text editor built to enable efficient editing	Nano A popular text editor, by default comes with most Linux distributions
Visual Studio Code Fast, hackable, multi-platform code editor from Microsoft

IT Asset Management

GLPI Information Resource-Manager with an additional Administration Interface	OCS Inventory NG Enables users to inventory their IT assets	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	Ralph Asset management, DCIM and CMDB system for large Data Centers as well as smaller LAN networks
Snipe IT Asset & license management software	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

Log Management

Echofish A web based real-time event log aggregation, analysis, monitoring and management system	Elasticsearch A Lucene Based Document store mainly used for log indexing, storage and analysis	Fluentd Log Collector and Shipper	Flume Distributed log collection and aggregation system	Graylog2 Pluggable Log and Event Analysis Server with Alerting options
Heka Stream processing system which may be used for log aggregation	Kibana Visualize logs and time-stamped data	Logstash Tool for managing events and logs	Octopussy Log Management Solution (Visualize / Alert / Report)

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

SMTP Servers

Exim Message transfer agent (MTA) developed at the University of Cambridge	Haraka A high-performance, pluginable SMTP server written in JavaScript	MailCatcher Ruby gem that deploys a simply SMTP MTA gateway that accepts all mail and displays in web interface Useful for debugging or development	Maildrop Open Source disposable email SMTP server, also useful for development	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)

Complete Mail Solutions

Mail-in-a-Box

Take back control of your email with this easy-to-deploy mail server in a box

iRedMail

Full-featured mail server solution based on Postfix and Dovecot

XMPP Messaging Servers

ejabberd XMPP instant messaging server written in Erlang/OTP	Metronome IM Fork of Prosody IM	MongooseIM Fullstack real-time mobile messaging platform (XMPP+REST) in Erlang	Openfire Real time collaboration (RTC) server	Prosody IM XMPP server written in Lua
Tigase XMPP server implementation in Java

XMPP Web Clients

Candy

Multi user XMPP client written in Javascript

Kaiwa

Web based chat client in the style of common paid alternatives

Webchats

Lets-Chat

A self hosted chat suite written in Node

Monitoring Software

Alerta Distributed, scaleable and flexible monitoring system	Canopsis Opensource Hypervision and Data Aggregation Software	Cacti Web-based network monitoring and graphing tool	Cabot Monitoring and alerts, similar to PagerDuty	Centreon IT infrastructure and application monitoring for service performance
check_mk Collection of extensions for Nagios	Flapjack Monitoring notification routing & event processing system	Icinga Fork of Nagios	LibreNMS fork of Observium	Monit Small Open Source utility for managing and monitoring Unix systems
Munin Networked resource monitoring tool	Naemon Network monitoring tool based on the Nagios 4 core with performance enhancements and new features	Nagios Computer system, network and infrastructure monitoring software application	OMD The Open Monitoring Distribution	Observium SNMP monitoring for servers and networking devices Runs on linux
Opsview Based on Nagios 4, Opsview Core is ideal for small IT and test environments	Riemann Flexible and fast events processor allowing complex events/metrics analysis	Sensu Open source monitoring framework	Sentry Application monitoring, event logging and aggregation	Serverstats A simple tool for creating graphs using rrdtool (source on github)
Seyren An alerting dashboard for Graphite	Shinken Another monitoring framework	Xymon Network monitoring inspired by Big Brother	Zabbix Enterprise-class software for monitoring of networks and applications	Zenoss Application, server, and network management platform based on Zope
Adagios Web based Nagios configuration interface	Dash A low-overhead monitoring web dashboard for a GNU/Linux machine	Thruk Multibackend monitoring web interface with support for Naemon, Nagios, Icinga and Shinken	Uchiwa Simple dashboard for the Sensu monitoring framework

Metric & Metric Collection

Collectd System statistic collection daemon	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	Smashing Ruby gem that allows for rapid statistical dashboard development An all HTML5 approach allows for big screen displays in data centers or conference rooms Fork of Dashing	Diamond Python based statistic collection daemon
Facette Time series data visualization and graphing software written in Go	Freeboard A damn-sexy front-end real-time dashboard Transforms raw JSON into delicious UI	Ganglia High performance, scalable RRD based monitoring for grids and/or clusters of servers Compatible with Graphite using a single collection process	Grafana A Graphite & InfluxDB Dashboard and Graph Editor	Graphite Open source scalable graphing server
InfluxDB Open source distributed time series database with no external dependencies	KairosDB Fast distributed scalable time series database, fork of OpenTSDB 1x	NetData Distributed real-time performance and health monitoring	OpenTSDB Store and server massive amounts of time series data without losing granularity	Prometheus Service monitoring system and time series database
RRDtool Open source industry standard, high performance data logging and graphing system for time series data	Statsd Application statistic listener

Network Configuration Management

GestióIP An automated web based IPv4/IPv6 IP Address Management tool	NOC Project Scalable, high-performance and open-source OSS system for ISP, service and content providers	Netbox IP address management (IPAM) and data center infrastructure management (DCIM) tool	Oxidized A modern take on network device configuration monitoring with web interface and GIT storage	phpIPAM Open source IP address management with PowerDNS integration
RANCID Monitors network device's configuration and maintain history of changes	rConfig Another network device configuration management tool	trigger Robust network automation toolkit written in Python

Newsletters

DadaMail

Mailing List Manager, written in Perl

phpList

Newsletter manager written in PHP

NoSQL

Apache HBase Hadoop database, a distributed, big data store	Cassandra Distributed DBMS designed to handle large amounts of data across many servers	Hypertable C++ based BigTable-like DBMS, communicates through Thrift and runs either as stand-alone or on distributed FS such as Hadoop	CouchDB Ease of use, with multi-master replication document-oriented database system	ElasticSearch Java based database, popular with log aggregation, and email archiving projects
MongoDB Another document-oriented database system	RavenDB Document based database with ACID/Transactional features	RethinkDB Open source distributed document store database, focuses on JSON	FlockDB Twitter's distributed, fault-tolerant graph database	Neo4j Open source graph database
Couchbase In-memory, replicated, peristent key/value datastore	LevelDB Google's high performance key/value database	Redis Networked, in-memory, key-value data store with optional durability	Riak Another fault-tolerant key-value NoSQL database

Packaging

fpm

Versatile multi format package creator

omnibus-ruby

Full stack, cross distro packaging software (Ruby)

packman

Full stack, cross distro packaging software (Python)

tito

Builds RPMs for git-based projects

Queuing

ActiveMQ An open source message broker written in Java together with a full JMS client	BeanstalkD A simple, fast work queue	Gearman Fast multi-language queuing/job processing platform	Kafka A high-throughput distributed messaging system	NSQ A realtime distributed messaging platform
RabbitMQ Robust, fully featured, cross distro queuing system	ZeroMQ High-performance asynchronous messaging library

Relational DBMS

Firebird True universal open source database	Galera Galera Cluster for MySQL is an easy-to-use high-availability solution with high system up-time, no data loss, and scalability for future growth	MariaDB Community-developed fork of the MySQL	MySQL Most popular RDBMS server	Percona Server Enhanced, drop-in MySQL replacement
PostgreSQL Object-relational database management system (ORDBMS)	PostgreSQL-XL Scalable Open Source PostgreSQL-based database cluster	SQLite Library that implements a self-contained, serverless, zero-configuration, transactional SQL DBS

Security

Blackbox Safely store secrets in Git/Mercurial Provides tooling to automatically encrypt secrets like passwords	Denyhosts Thwart SSH dictionary based attacks and brute force attacks	Fail2Ban Scans log files and takes action on IPs that show malicious behavior	fwknop Protects ports via Single Packet Authorization in your firewall	Glastopf A low-interaction web application honeypot to emulate vulnerabilities and gather attack data
Kippo A medium-interaction SSH honeypot, mostly used as a standalone SSH daemon with a configurable Filesystem sandbox	OSSEC OSSEC is a HIDS that performs log analysis, FIM, rootkit detection, and much more	OSQuery Query your servers status and info using a SQL like interface	pfSense Firewall and Router FreeBSD distribution	Snort Snort is a free and open source network intrusion prevention system (NIPS) and network intrusion detection system (NIDS) created by Martin Roesch in 1998
SpamAssassin A powerful and popular email spam filter employing a variety of detection technique	BounCA BounCA is a personal SSL / Certificate Authority Key management tool Create self-signed SSL certificates via your browser (Source Code) Apache Python

Service Discovery

Consul

Consul is a tool for service discovery, monitoring and configuration

Doozerd

Doozer is a highly-available, completely consistent store for small amounts of extremely important data

ZooKeeper

ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services

Software Containers

Bitnami Produces open source installers or software packages for web applications and development stacks as well as virtual appliances	Docker Open platform for developers and sysadmins to build, ship, and run distributed applications	LXC Userspace interface for the Linux kernel containment features	LXD LXD is a container "hypervisor"	OpenVZ Container-based virtualization for Linux
Docker Compose Fast, isolated development environments using Docker	Singularity Flexible containers without root

SSH

Advanced SSH config Enhances ssh_config file capabilities, completely transparent	autossh Automatically respawn ssh session after network interruption	Cluster SSH Controls a number of xterm windows via a single graphical console	DSH Dancer's shell / distributed shell Wrapper for executing multiple remote shell commands from one command line	Mosh The mobile shell
parallel-ssh Provides parallel versions of OpenSSH and related tools	pdsh Pdsh is a high-performance, parallel remote shell utility	SSH Power Tool Execute commands and upload files to many servers simultaneously without using pre-shared keys	sshrc sources ~/sshrc on your local computer after logging in remotely	stormssh A command line tool to manage SSH connections

Statistics

Analog Logfile Analyser	AWStats Generates web, streaming, ftp or mail server statistics graphically	GoAccess Real-time web log analyzer and interactive viewer that runs in a terminal	Open Web Analytics Add web analytics to websites using JS, PHP or REST APIs	Piwik Web analytics application
Webalizer Fast, free web server log file analysis program

Status Pages

Cachet

An open source status page system written in PHP

Ticketing Systems

Bugzilla General-purpose bugtracker and testing tool originally developed and used by the Mozilla project	Cerb Group-based e-mail management project	Flyspray Web-based bug tracking system written in PHP	MantisBT Web-based bug tracking system	osTicket Simple support ticket system
OTRS Trouble ticket system for assigning tickets to incoming queries and tracking further communications	Redmine Open source project management/ticketing web application written in Ruby	Request Tracker Ticket-tracking system written in Perl	TheBugGenie Ticket system with extensive user rights system

Troubleshooting

mitmproxy

A Python tool used for intercepting, viewing and modifying network traffic Invaluable in troubleshooting certain problems

Sysdig

Capture system state and activity from a running Linux instance, then save, filter and analyze

Wireshark

The world's foremost network protocol analyzer

Trinity Rescue Kit

Linux Live CD for general computer troubleshooting

Project Management

ChiliProject Fork of Redmine	GitBucket GitHub Clone written in Scala; single jar install	GitLab Clone of GitHub written in Ruby	Gogs Self-hosted Git service written in Go	OpenProject Project collaboration with open source
Phabricator Written in PHP	Redmine Written in ruby on rails	Taiga Agile, Free, Open Source Project Management Tool based on the Kanban and Scrum methods	The Bug Genie Written in PHP	Trac Written in python

Version Control

Fossil

Distributed version control with built-in wiki and bug tracking

Git

Distributed revision control and source code management (SCM) with an emphasis on speed

GNU Bazaar

Distributed revision control system sponsored by Canonical

Mercurial

Another distributed revision control

Subversion

Client-server revision control system

Virtualization

Archipel XMPP based virtualization management platform	Ganeti Cluster virtual server management software tool built on top of KVM and Xen	KVM Linux kernel virtualization infrastructure	OpenNebula Flexible enterprise cloud made simple	oVirt Manages virtual machines, storage and virtual networks
Packer A tool for creating identical machine images for multiple platforms from a single source configuration	Proxmox VE Complete open source virtualization management solution	QEMU QEMU is a generic and open source machine emulator and virtualizer	Vagrant Tool for building complete development environments	VirtualBox Virtualization product from Oracle Corporation
Xen Virtual machine monitor for 32/64 bit Intel / AMD (IA 64) and PowerPC 970 architectures

VPN

OpenVPN Uses a custom security protocol that utilizes SSL/TLS for key exchange	Pritunl OpenVPN based solution Easy to set up	SoftEther Multi-protocol software VPN with advanced features	sshuttle Poor man's VPN	strongSwan Complete IPsec implementation for Linux
tinc Distributed p2p VPN	wireguard New minimal VPN Solution that is very fast

Web Servers

Apache Most popular web server	Caddy The HTTP/2 Web Server with Fully Managed TLS	Cherokee Lightweight, high-performance web server/reverse proxy	Lighttpd Web server more optimized for speed-critical environments	Nginx Reverse proxy, load balancer, HTTP cache, and web server
uWSGI The uWSGI project aims at developing a full stack for building hosting services

Web Performance

HAProxy

Software based load Balancing, SSL offloading and performance optimization, compression, and general web routing

Squid

Caching proxy for the web supporting HTTP, HTTPS, FTP, and more

Traefik

Træfɪk is a modern HTTP reverse proxy and load balancer made to deploy microservices with ease

Varnish

HTTP based web application accelerator focusing on optimizing caching and compression

Webmails

Mailpile

A modern, fast web-mail client with user-friendly encryption and privacy features

Roundcube

Browser-based IMAP client with an application-like user interface

SquirrelMail

Another browser-based IMAP client

Wiki Software

BookStack A simple, user-friendly wiki built with PHP that uses MySQL for storage	DokuWiki Simple to use and highly versatile wiki that doesn't require a database	Gollum A simple, Git-powered wiki with a sweet API and local frontend	ikiwiki A wiki compiler	MDwiki Wiki completely built in HTML5/Javascript and runs 100% on the client
MediaWiki Used to power Wikipedia	MoinMoin An advanced, easy to use and extensible WikiEngine with a large community of users	Ōlelo Wiki A a wiki that stores pages in a Git repository	TiddlyWiki Complete interactive wiki in JavaScript