Awesome Sysadmin

A curated list of amazingly awesome open source sysadmin resources. You can check out other awesome lists as well. Please read CONTRIBUTING if you wish to add software.

• Awesome Sysadmin
  • Automation
  • Backups
  • ChatOps
  • Cloning
  • Cloud Computing
  • Cloud Storage
  • Code Review
  • Collaborative Software
  • Configuration Management Database
  • Configuration Management
  • Continuous Integration & Continuous Deployment
  • Distributed Filesystems
  • DNS
  • Editors
  • Hosting Control Panels
  • IT Asset Management
  • LDAP
  • Log Management
  • Mail Clients
  • Mail Servers
  • Monitoring
  • Metric & Metric Collection
  • Network Configuration Management
  • Newsletter
  • NoSQL
  • Packaging
  • Queuing
  • RDBMS
  • Security
  • Service Discovery
  • Software Containers
  • SSH
  • Statistics
  • Status Pages
  • Ticketing systems
  • Troubleshooting
  • Project Management
  • Version control
  • Virtualization
  • VPN
  • XMPP
  • Web
  • Wikis
• Resources
  • Blogs
  • Books
  • Newsletters
  • Repositories
  • Websites

Automation

Automation build.

• Apache Ant - Automation build tool, similar to make, written in Java.
• Apache Maven - Build automation tool mainly for Java.
• GNU Make - The most popular automation build tool for many purposes.
• Gradle - Another open source build automation system.

Backups

Backup software.

• Amanda - Client-server model backup tool.
• Bacula - Another Client-server model backup tool.
• Bareos - A fork of Bacula backup tool.
• Backupninja - Lightweight, extensible meta-backup system.
• Backuppc - Client-server model backup tool with file pooling scheme.
• Brebis - A fully automated backup checker
• Burp - Network backup and restore program.
• Duplicity - Encrypted bandwidth-efficient backup using the rsync algorithm.
• Lsyncd - File Monitor which spawns a process to synchronize the changes (rsync by default).
• Rsnapshot - Filesystem Snapshotting Utility.
• SafeKeep - Centralized pull-based backup using rdiff-backup.
• TarSnap - Secure backup service with an open-source client.
• UrBackup - Another client-server backup system.
• DREBS - AWS EBS backup script that supports strategies.
• ZBackup - A versatile deduplicating backup tool

ChatOps

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

• Eggdrop - the world's most popular Open Source 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.

Cloning

Cloning software.

• 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.
• Eucalyptus - Open source private cloud software with AWS compatibility.
• Mesos - Develop and run resource-efficient distributed systems.
• OpenNebula - An user-driven cloud management platform for sysadmins and devops.
• 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.

Cloud Orchestration

• BOSH - IaaS orchestration platform originally written for deploying and managing Cloud Foundry PaaS, but also useful for general purpose distributed systems.
• Cloudify - Open source TOSCA-based cloud orchestration software platform written in Python and YAML.
• Juju - Cloud orechestration 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.
• StackStorm - Event Driven Operations and ChatOps platform for infrastructure management. Written in Python

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.
• 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 distrobution of data.

Code Review

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.
• Review Board - Available as free software uner the MIT License.

Collaborative Software

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

Configuration management database (CMDB) software.

• 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 encyclopedia toolkit (based on mediawiki).
• 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.

Configuration Management

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.

Build and software organization tools

Build and software organization tools.

• EasyBuild - EasyBuild builds software and modulefiles for High Performance Computing (HPC) systems in an efficient way.
• environment-modules Tcl - .
• environment-modules Lmod - Lmod is a Lua based module system that easily handles the MODULEPATH Hierarchical problem.
• environment-modules Tcl/C - The Environment Modules package provides for the dynamic modification of a user's environment via modulefiles.
• HPCBIOS - HPCBIOS is an effort to setup a common, well-documented and reproducible, environment spanning across multiple HPC systems & sites, inclusive of documentation.

Continuous Integration & Continuous Deployment

Continuous integration/deployment software.

• 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.

Deployment Automation

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).

Distributed Filesystems

Network distributed filesystems.

• Ceph - Distributed object store and file system.
• DRBD - Disributed 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

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

Open source code 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.
• 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
• TextMate - A graphical text editor for OS X.
• Vim - A highly configurable text editor built to enable efficient editing.

Hosting Control Panels

Web hosting control panels

• Ajenti - Control panel for Linux and BSD.
• 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.

IT Asset Management

IT Assets Management software.

• GLPI - Information Resource-Manager with an additional Administration Interface.
• OCS Inventory NG - Enables users to inventory their IT assets.
• 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.

LDAP

LDAP servers.

• 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.

Log Management

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.
• 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 Clients

• Claws Mail - Old school email client (and news reader), based on GTK+.
• Mutt - Small but very powerful text-based mail client.
• Thunderbird - Free email application that's easy to set up and customize.

Webmail

Webmail applications.

• 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.

Mail Servers

Software for setting up mail servers.

MDA (IMAP/POP3)

Mail Delivery Agents (IMAP/POP3 software).

• 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.

MTA (SMTP)

Mail Transfer Agents (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 solutions

Software for simple deployment of a mail server, e.g. for inexperienced or impatient admins.

• 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.

Monitoring

Monitoring software.

• Cacti - Web-based network monitoring and graphing tool.
• Cabot - Monitoring and alerts, similar to PagerDuty.
• check_mk - Collection of extensions for Nagios.
• Dash - A low-overhead monitoring web dashboard for a GNU/Linux machine.
• 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.
• 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.
• Opsmatic - Configuration monitoring software for your infrastructure with automatic drift detection.
• 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.
• Shinken - Another monitoring framework.
• Thruk - Multibackend monitoring webinterface with support for Naemon, Nagios, Icinga and Shinken.
• 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 & Metric Collection

Metric gathering and display software.

• Collectd - System statistic collection daemon.
• Collectl - High precision system performance metrics collecting tool.
• 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.
• 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 scaleable graphing server.
• InfluxDB - Open source distributed time series database with no external dependencies.
• KairosDB - Fast distributed scalable time series database, fork of OpenTSDB 1.x.
• OpenTSDB - Store and server massive amounts of time series data without losing granularity.
• Prometheus - An open-source 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

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 interace and GIT storage.
• RANCID - Monitors network device's configurarion and maintain history of changes.
• rConfig - Another network device configuration management tool.
• trigger - Robust network automation toolkit written in Python.

Newsletters

Newsletter software.

• DadaMail - Mailing List Manager, written in Perl.
• phpList - Newsletter manager written in PHP.

NoSQL

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 - Open source distributed document store database, focuses on JSON.
• Graph
  • FlockDB - Twitter's distributed, fault-tolerant graph database.
  • Neo4j - Open source 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

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

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

RDBMS

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

Security tools.

• Blackbox - Safely store secrets in Git/Mercurial. Privides 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.
• 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 techniques.

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

Operating system–level virtualization.

• 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.
• OpenVZ - Container-based virtualization for Linux.

SSH

SSH tools.

• 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.
• SSH Power Tool - Execute commands and upload files to many servers simultaneously without using pre-shared keys.
• stormssh - A command line tool to manage SSH connections.

Statistics

Analytics software.

• 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 web server log file analysis.

Status Pages

• StatusPage.io - Hosted Status Page Platform.
• Cachet - An open source status page system written in PHP.

Ticketing systems

Web-based ticketing system.

• 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.
• Request Tracker - Ticket-tracking system written in Perl.
• TheBugGenie - Ticket system with extensive user rights system.

Troubleshooting

Troubleshooting Tools.

• 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.
• Trinity Rescue Kit - Linux Live CD for general computer troubleshooting.
• Wireshark - The world's foremost network protocol analyzer.

Project Management

Web-based project management and bug tracking systems.

• ChiliProject - Fork of Redmine.
• GitBucket Clone of GitHub 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

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

Virtualization software.

• Ganeti - Cluster virtual server management software tool built on top of KVM and Xen.
• KVM - Linux kernel virtualization infrastructure.
• oVirt - Manages virtual machines, storage and virtual networks.
• Packer - A tool for creating identical machine images for multiple platforms from a single source configuration.
• 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

VPN software.

• 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.

XMPP

XMPP servers.

• ejabberd - XMPP instant messaging server written in Erlang/OTP.
• Metronome IM - Fork of Prosody IM.
• MongooseIM - Fork of ejabberd.
• Openfire - Real time collaboration (RTC) server.
• Prosody IM - XMPP server written in Lua.
• Tigase - XMPP server implementation in Java.

Web

Web servers.

• Apache - Most popular web server.
• 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.
• Varnish - HTTP based web application accelerator focusing on optimizing caching and compression.

Wikis

Wiki software.

• 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.
• 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.

Resources

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

Blogs

• 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.

Books

Sysadmin related 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.
• 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 - Approaches system administration from a practical perspective.

Newsletters

• Servers for Hackers - Newsletter for programmers who find themselves needing to know their way around a server.

Repositories

Software package repositories.

• AlternativeTo - Find alternatives to software you know and discover new software.
• Dotdeb - Repository with LAMP updated packages for Debian.
• Remi - Repository with LAMP updated packages for RHEL/Centos/Fedora.

Websites

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.