A curated list of amazingly awesome open source sysadmin resources. Please read CONTRIBUTING if you wish to add software and consider donating to the FLOSS projects you use regularly.

• Awesome Sysadmin
  • Automation
  • Backups
  • Build and software organization tools
  • ChatOps
  • Client Management
  • Cloning
  • Cloud Computing
  • Cloud Orchestration
  • Cloud Storage: see awesome-selfhosted#file-transfersynchronization
  • Code Review
  • Collaborative Software
  • Configuration Management Database
  • Configuration Management
  • Continuous Integration & Continuous Deployment
  • Control Panels
  • Deployment Automation
  • Distributed Filesystems
  • DNS
  • Editors
  • Identity Management
  • IT Asset Management
  • Log Management
  • Mail Clients
  • Mail servers/webmail: see awesome-selfhosted#email
  • Monitoring
  • Metric & Metric Collection
  • Network Configuration Management
  • Newsletter
  • NoSQL
  • Packaging
  • Project Management
  • Queuing
  • RDBMS
  • Remote Management
  • Security: see awesome-security
  • Service Discovery
  • Software Containers
  • SSH: see awesome-ssh
  • Statistics: see awesome-selfhosted#analytics
  • Status Pages
  • Ticketing systems: see awesome-selfhosted#ticketing
  • Troubleshooting
  • Version control
  • Virtualization
  • VPN
  • XMPP: see awesome-selfhosted#xmpp
  • Web
  • Wiki Software: see awesome-selfhosted#wikis, Sysadmin Wikis: see #wikis
• Resources
  • Blogs
  • Books
  • Communities/Forums
  • Newsletters
  • Repositories
  • Websites
  • Wikis

Automation build.

• Apache Ant - Automation build tool, similar to make, written in Java.
• Apache Maven - Build automation tool mainly for Java.
• Bazel - Google's build system.
• GNU Make - The most popular automation build tool for many purposes.
• Gradle - Another build automation system.
• Rake - Build automation tool similar to Make, written in and extensible in Ruby.

Backup software.

• Amanda - Client-server model backup tool.
• Bareos - A fork of Bacula backup tool.
• Backupninja - Lightweight, extensible meta-backup system.
• BorgBackup - A fork of Attic deduplicating backup program written in Python.
• Brebis - A fully automated backup checker
• Burp - Network backup and restore program.
• Duplicity - Encrypted bandwidth-efficient backup using the rsync algorithm.
• Elkarbackup - Backup solution based on RSnapshot with a simple web interface
• Lsyncd - File Monitor which spawns a process to synchronize the changes (rsync by default).
• Obnam - An easy, secure, snapshots-based backup program with data de-duplication.
• Rdiff-backup - An easy A remote incremental backup of all your files.
• Rsnapshot - Filesystem Snapshotting Utility.
• Shield - A pluggable architecture for backup and restore of database systems.
• Snebu – Snapshot backup with global multi-client deduplication and transparent compression.
• UrBackup - Another client-server backup system.
• DREBS - AWS EBS backup script that supports strategies.
• ZBackup - A versatile deduplicating backup tool.

Build and software organization tools.

• EasyBuild - EasyBuild builds software and modulefiles for High Performance Computing (HPC) systems in an efficient way.
• environment-modules Lmod - Lmod is a Lua based module system that easily handles the MODULEPATH Hierarchical problem.
• HPCBIOS - HPCBIOS is an effort to setup a common, well-documented and reproducible, environment spanning across multiple HPC systems & sites, inclusive of documentation.

Conversation-driven development and management. See https://www.reddit.com/r/chatops for more information.

• CloudBot - The simple, fast, expandable Python IRC bot.
• Eggdrop - the world's most popular IRC bot, designed for flexibility and ease of use, and is freely distributable under the GNU GPL.
• Err - a plugin based chatbot designed to be easily deployable, extensible and maintainable.
• Hubot - A customizable, life embetterment robot.
• Lazlo - A chatops automation framework in Go.
• Lita - A robot companion for your company's chat room.
• Abot - A digital assistant framework in Go.

Managing software on desktop computers.

• Chocolatey – Windows CLI package manager written in .NET/PS, based on NuGet.
• just-install – Python script for downloading and silently installing MSI files.
• OCS Inventory NG - Inventory, deployment and network scan.
• Opsi (open PC server integration) - Client Management for Windows based on Debian.
• WAPT - Network-wide (un)installation, configuration and upgrades of Windows based software.
• WPKG - Software deployment, upgrade and removal program for Windows.

Cloning software.

• Clonezilla - Partition and disk imaging/cloning program.
• Fog - Another computer cloning solution.

• AppScale - 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.
• Cracow Cloud One - Polish Private Cloud - The CC1 system provides a complete solution for Private Cloud Computing.
• HPE Helion Eucalyptus - Private cloud software with AWS compatibility.
• Flynn - PaaS
• Mesos - Develop and run resource-efficient distributed systems.
• OpenNebula - User-driven cloud management platform for sysadmins and devops.
• Openshift - PaaS product from Red Hat.
• OpenStack - Build private and public clouds.
• The Foreman - Complete lifecycle management tool for physical and virtual servers. FOSS.
• Tsuru - Tsuru is an extensible Platform as a Service software.

• BOSH - IaaS orchestration platform originally written for deploying and managing Cloud Foundry PaaS, but also useful for general purpose distributed systems.
• Cloud Foundry - A Platform-as-a-Service suite to provide the orchestration services that make distributed apps a powerhouse of awesomeness.
• Cloudify - TOSCA-based cloud orchestration software platform written in Python and YAML.
• CloudSlang - Flow-based orchestration tool for managing deployed applications, with Docker capabilities.
• Genesis - A template framework for multi-environment BOSH deployments.
• Juju - Cloud orchestration tool which manages services as charms, YAML configuration and deployment script bundles.
• Kubernetes - Orchestration system for Docker containers - (Source Code, Documentation) Apache Go
• 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.
• Spruce - A tool that merges separate YAML files into one. Works well with Genesis.
• StackStorm - Event Driven Operations and ChatOps platform for infrastructure management. Written in Python

Web Based collaborative code review system.

• 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 - Available as free software under the MIT License.

Collaborative software or groupware suites.

• 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 (CMDB) software.

• i-doit - IT Documentation and CMDB.
• iTop - Complete ITIL web based service management tool.
• Ralph - Asset management, DCIM and CMDB system for large Data Centers as well as smaller LAN networks.
• 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.
• netbox - IP address management (IPAM) and data center infrastructure management (DCIM) tool

Configuration management tools.

• 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.
• 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.
• Salt - It's written in Python.
• Slaughter - It's written in Perl.

Continuous integration/deployment software.

• Buildbot - Python-based toolkit for continuous integration.
• CapsuleCD - CD script for automating package/library releases (npm, cookbooks, gems, pip, jars, etc).
• concourse - A modern tool to gain visibility on the CI/CD pipeline. The flexible, declarative DSL is easy to learn and powerful to use.
• 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 - Continuous delivery server.
• Jenkins - An extendable continuous integration server.

Web hosting and server or service control panels

• Web hosting
  • 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 - Hosting panel for Linux based on webmin.
• DNS
  • Atomia DNS - DNS management system.
  • PDNS Gui - WebGUI which aids in administering domains and records for PowerDNS with MySQL.
  • Poweradmin - Friendly web-based DNS administration tool for PowerDNS server.
• Revision Control
  • iF.SVNAdmin - WebGUI to manage Subversion repositories and User/Group permissions.
  • SCM-Manager - The easiest way to share and manage your Git, Mercurial and Subversion repositories.
  • WebSVN - Opensource web subversion repository browser.
• Virtualization
  • Feathur - VPS Provisioning and Management Software.
  • Panamax - Project that makes deploying complex containerized apps as easy as Drag-and-Drop.
  • OpenVZ Web Panel - Web panel to control OpenVZ virtual machines.
  • WebVirtMgr - libvirt-based Web interface for managing virtual machines.
• Server
  • Ajenti - Control panel for Linux and BSD.
  • Cockpit - New multi-server web interface for Linux servers written in C.
  • Webmin - Linux server control panel.

Tools and scripts to support deployments to your servers.

• 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).

Network distributed filesystems.

• Camlistore - A set of open source formats, protocols, and software for modeling, storing, searching, sharing and synchronizing data.
• 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.
• Go IPFS - Implementation of IPFS, a global, versioned, peer-to-peer filesystem that seeks to connect all computing devices with the same system of files.
• HDFS - Distributed, scalable, and portable file-system written in Java for the Hadoop framework.
• Lustre - 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.
• Ori Filesystem - A Secure Distributed File System built for offline operation.
• Swift - A highly available, distributed, eventually consistent object/blob store.
• 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.

Open source code editors.

• Atom - A hackable text editor from Github.
• Brackets - 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.
• jotgit - Git-backed real-time collaborative code editing.
• KDevelop - IDE by the people behind KDE.
• Light Table - The next generation code editor.
• Lime - Aims to provide an open source solution to Sublime Text
• TextMate - A graphical text editor for OS X.
• Vim - A highly configurable text editor built to enable efficient editing.
• Visual Studio Code - An open source cross-platform extensible code editor from Microsoft
• Nano - Easy to use, customizable text editor.

LDAP servers and other tools to manage accounts and identities.

• 389 Directory Server - Developed by Red Hat.
• Apache Directory Server - Apache Software Foundation project written in Java.
• FreeRADIUS - High performance and highly configurable multi-protocol policy/authentication server, supporting RADIUS, DHCPv4 and VMPS.
• OpenDJ - Fork of OpenDS.
• OpenDS - Another directory server written in Java.
• OpenLDAP - Developed by the OpenLDAP Project.

• Fusion Directory - Improve the Management of the services and the company directory based on OpenLDAP.
• FreeIPA - Security management solution, can manage LDAP, KRB, DNS, sudo, and more.
• Indieauth - Sign in with your domain name (using the rel-me-auth protocol).
• Libravatar - Libravatar is a service which delivers your avatar (profile picture) to other websites.
• LDAP Account Manager (LAM) - Web frontend for managing entries (e.g. users, groups, DHCP settings) stored in an LDAP directory.
• OpenID - A Simple Identity layer on top of OAuth 2.0.
• OSIAM - Secure identity management solution providing REST based services for authentication and authorization.
• Samba – Active Directory and CIFS protocol implementation.
• BounCA - A personal SSL Key / Certificate Authority web-based tool for creating self-signed certificates.

IT Assets Management software.

• GLPI - Information Resource-Manager with an additional Administration Interface.
• OCS Inventory NG - Enables users to inventory their IT assets.
• OPSI - Hardware and software inventory, deployment, and patching for Linux and Windows.
• 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.

Log management tools: collect, parse, visualize ...

• 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.
• GoAccess - Real-time web log analyzer and interactive viewer that runs in a terminal or through the browser. (Source Code) MIT C
• Graylog - 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).

• Claws Mail - Old school email client (and news reader), based on GTK+.
• ImapSync – Simple IMAP migration tool for copying mailboxes to other servers.
• Mutt - Small but very powerful text-based mail client.
• N1 - Extensible mail client.
• Sylpheed – Still developed predecessor to Claws Mail, lightweight mail client.
• Thunderbird - Free email application that's easy to set up and customize.

Monitoring software.

• Adagios - Web based Nagios interface for configuration and monitoring (replacement to the standard interface), and a REST interface, SourceCode, Documentation)
• Alerta - Distributed, scaleable and flexible monitoring system.
• Bloonix - Bloonix is a monitoring solution that helps businesses to ensure high availability and performance. GPLv3 Perl
• bolo - A Do-it-Yourself monitoring framework built to gather metrics, mine data and report on the systems in your network.
• Bosun - Monitoring and alerting system by Stack Exchange (Source Code, Documentation) MIT Go
• Cacti - Web-based network monitoring and graphing tool.
• Cabot - Monitoring and alerts, similar to PagerDuty.
• cadvisor - Analyzes resource usage and performance characteristics of running containers (Source Code) Apache Go
• check_mk - Collection of extensions for Nagios.
• Dash - A low-overhead monitoring web dashboard for a GNU/Linux machine.
• Flapjack - Monitoring notification routing & event processing system.
• Healthchecks - Monitoring for cron jobs, background services and scheduled tasks.
• Icinga - Nagios fork that has since lapped nagios several times. Comes with the possibility of clustered monitoring - (Source Code) - GPLv2
• LibreNMS - Fully featured network monitoring system that provides a wealth of features and device support.
• Monit - Small 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.
• Node-Bell - Real-time anomalies detection for periodic time series, metrics monitor.
• Observium - SNMP monitoring for servers and networking devices. Runs on linux.
• OMD - The Open Monitoring Distribution.
• PhpSysInfo - A customizable PHP script that displays information about your system nicely.
• psdash - A linux system information web dashboard using psut ils and flask.
• pyDash - Small web-based monitoring dashboard for linux.
• Riemann - Flexible and fast events processor allowing complex events/metrics analysis.
• Sensu - Monitoring framework.
• Sentry - Application monitoring, event logging and aggregation.
• ServerStatus BotoX - Display and monitor your servers statistics in a beatiful way.
• ServerStatus moejda - Server Status website script, displays uptime (days), free RAM, free HDD
• Shinken - Another monitoring framework.
• Thruk - Multibackend monitoring web interface with support for Naemon, Nagios, Icinga and Shinken.
• Uchiwa - Simple dashboard for sensu.
• 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.

Metric gathering and display software.

• Collectors only

  • Diamond - Python based statistic collection daemon.
  • Collectd - System statistic collection daemon.
  • Collectl - High precision system performance metrics collecting tool.
  • PGObserver - Monitoring solution for PostgreSQL databases that also works with AWS RDS.
  • Statsd - Application statistic listener.
  • tcollector - System statistic collection daemon written in Python for OpenTSDB

• Dashboards

  • Grafana - A Graphite & InfluxDB Dashboard and Graph Editor.
  • Ganglia - High performance, scalable RRD based monitoring for grids and/or clusters of servers. Compatible with Graphite using a single collection process.
  • RRDtool - Industry standard, high performance data logging and graphing system for time series data.
  • Dashing - Ruby gem that allows for rapid statistical dashboard development. An all HTML5 approach allows for big screen displays in data centers or conference rooms.
  • Facette - Time series data visualization and graphing software written in Go.
  • Freeboard - A damn-sexy front-end real-time dashboard for the internet of things. Transforms raw JSON into delicious UI.
  • Netdata - Real-time performance monitoring for Linux systems with plugin support.

• Storage

  • OpenTSDB - Store and server massive amounts of time series data without losing granularity.
  • KairosDB - Fast distributed scalable time series database, fork of OpenTSDB 1.x.
  • InfluxDB - Distributed time series database with no external dependencies.

• Packages

  • Prometheus - Service monitoring system and time series database.
  • Packetbeat - Captures network traffic and displays it in a custom Kibana dashboard for easy viewing.
  • Graphite - Scalable graphing server.

Network configuration management tools.

• GestióIP - An automated web based IPv4/IPv6 IP Address Management tool.
• Oxidized - A modern take on network device configuration monitoring with web interface and GIT storage.
• 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.

Newsletter software.

• DadaMail - Mailing List Manager, written in Perl.
• phpList - Newsletter manager written in PHP.
• LibreMailer - Libre Mailer is a modest and simple web based email marketing application.
• Lewsnetter - E-mail marketing application (create and send e-mail newsletter via SES). Includes subscription management, delivery, bounce and complaint notification, templates, and some stats.

NoSQL databases.

• Column-Family
  • 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.
• Document Store
  • 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 - Distributed document store database, focuses on JSON.
• Graph
  • FlockDB - Twitter's distributed, fault-tolerant graph database.
  • Neo4j - Graph database.
• Key-Value
  • 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.

Comparison of NoSQL servers: http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis

• 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.

Web-based project management and bug tracking systems: see https://github.com/Kickball/awesome-selfhosted#project-management

• ActiveMQ - Java message broker.
• BeanstalkD - A simple, fast work queue.
• Gearman - Fast multi-language queuing/job processing platform.
• Kafka - Extremely high performance publish/subscribe message system.
• NSQ - A realtime distributed messaging platform.
• RabbitMQ - Robust, fully featured, cross distro queuing system.
• ZeroMQ - Lightweight queuing system.

Relational DBMS.

• Firebird - True universal 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.
  • adminer - Database management in a single PHP file (Source code)
• Percona Server - Enhanced, drop-in MySQL replacement.
• PostgreSQL - Object-relational database management system (ORDBMS).
• PostgreSQL-XL - Scalable PostgreSQL-based database cluster.
• SQLite - Library that implements a self-contained, serverless, zero-configuration, transactional SQL DBS.

• Tiger VNC - TigerVNC is a high-performance, platform-neutral implementation of VNC (Virtual Network Computing), a client/server application that allows users to launch and interact with graphical applications on remote machines.
• Remmina - A Feature rich remote desktop application for linux and other unixes.
• X2go - X2Go is an open source remote desktop software for Linux that uses the NX technology protocol.

• 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.
• etcd - distributed K/V-Store, authenticating via SSL PKI and a REST HTTP Api for shared configuration and service discovery.
• ZooKeeper - ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services.

Operating system–level virtualization.

• Docker - Platform for developers and sysadmins to build, ship, and run distributed applications.
• LXC - Userspace interface for the Linux kernel containment features.
• OpenVZ - Container-based virtualization for Linux.

• Cachet - Status page system written in PHP.
• Stashboard - Status page for cloud services and APIs.
• System Status Dashboard (SSD) - Overview about an organization's infrastructure health status.
• Staytus - Staytus is a complete solution for publishing the latest information about any issues with your web applications, networks or services.

Troubleshooting Tools.

• grml – bootable Debian Live CD with powerful CLI tools.

• mitmproxy - A Python tool used for intercepting, viewing and modifying network traffic. Invaluable in troubleshooting certain problems.
• perf-tools - Performance analysis tools based on Linux perf_events (aka perf) and ftrace.
• Sysdig - Capture system state and activity from a running Linux instance, then save, filter and analyze.
• Dripcap - Caffeinated Packet Analyzer.
• Wireshark - The world's foremost network protocol analyzer.

Software versioning and revision 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 software.

• Archipel - XMPP based virtualization management platform.
• ConVirt - Provides the core functionality for centrally managing your KVM or Xen virtualized environment.
• 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.
• OpenNode - Builds open-source infrastructure management software and implements cloud systems.
• Otto - Development and deployment system designed as the successor to Vagrant.
• 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 - Virtualization management solution.
• QEMU - QEMU is a generic 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.
• XenServer - Turnkey virtualization platform based on CentOS distribution, using Xen and an extended toolstack/API.

VPN software.

• ocserv - Cisco AnyConnect-compatible VPN server
• 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.

Web servers.

• Algernon - Web/application server that supports Lua, live-reload, templates, Sass and HTTP/2.
• Apache - Most popular web server.
• Caddy - Lightweight, general-purpose web server supporting HTTP/2, automatic TLS and easy configuration. Written in Go.
• Cherokee - Lightweight, high-performance web server/reverse proxy.
• Hiawatha - Prioritises security, simplicity and performance.
• 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.
• Varnish - HTTP based web application accelerator focusing on optimizing caching and compression.

Various resources, such as books, websites and articles, for improving your skills and knowledge.

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

Sysadmin related books.

• Codex - How to deploy Cloud Foundry PaaS on infrastructures like AWS, OpenStack, Azure by Stark & Wayne, LLC.
• 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.
• The Visible Ops Handbook: Implementing ITIL in 4 Practical and Auditable Steps - Is a methodology designed to jumpstart implementation of controls and process improvement.
• UNIX and Linux System Administration Handbook (ISBN-13: 978-0131480056) - Approaches system administration from a practical perspective.

For the social people.

• ArsTechnica OpenForum – IT Forum which is attached to a large news site.
• Reddit - Really, really large bulletin board system.
  • /r/Linux - News and information about Linux.
  • /r/LinuxQuestions
  • /r/SysAdmin
• Spiceworks Community – General enterprise IT news and small articles.
• StackExchange Network – Q&A communities.
  • Server Fault – StackExchange community for system and network administrators.

• Servers for Hackers - Newsletter for programmers who find themselves needing to know their way around a server.
• Web Operations Weekly - A weekly newsletter on Web operations, infrastructure, performance, and tooling, from the browser down to the metal.

Software package repositories.

• AlternativeTo - Find alternatives to software you know and discover new software.

• Dotdeb - Repository with LAMP updated packages for Debian.

• ElRepo - Community Repo for Enterprise Linux (RHEL, CentOS, etc).
• EPEL - Repository for RHEL and compatibles (CentOS, Scientific Linux).
• IUS - Community project that provides RPM packages for newer versions of select software for Enterprise Linux distributions.
• Remi - Repository with LAMP updated packages for RHEL/Centos/Fedora.
• Software Collections - Community Release of Red Hat Software Collections. Provides updated packages of Ruby, Python, etc. for CentOS/Scientific Linux 6.x.

Useful sysadmin related websites.

• Ops School - Comprehensive program that will help you learn to be an operations engineer.
• Digital Ocean Tutorials - A surprisingly vast resource for getting the basics of certain applications, tools, or even systems administration topics.

Useful Wikis for Sysadmins – not to be confused with Wiki software.

• ArchWiki – Arch Linux Wiki which has really nice written articles valid for other distros.
• Gentoo Wiki - Gentoo Linux Wiki with a lot in-detail description of Linux components.

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