Ansible is a suite of software tools that enables

infrastructure as code Infrastructure as code (IaC) is the process of managing and provisioning computer data centers through machine-readable definition files, rather than physical hardware configuration or interactive configuration tools. The IT infrastructure manage ...

. It is

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

and the suite includes software

provisioning In telecommunication, provisioning involves the process of preparing and equipping a network to allow it to provide new services to its users. In National Security/Emergency Preparedness telecommunications services, ''"provisioning"'' equates to ...

configuration management Configuration management (CM) is a process for establishing and maintaining consistency of a product's performance, functional, and physical attributes with its requirements, design, and operational information throughout its life. The CM proc ...

, and application deployment functionality. Originally written by Michael DeHaan and acquired by

Red Hat Red Hat, Inc. is an American software company that provides open source software products to enterprises. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina, with other offices worldwide. Red Hat has become ass ...

in 2015, Ansible is designed to configure both

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

systems and

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

. Ansible is

agentless In computer science, a software agent or software AI is a computer program that acts for a user or other program in a relationship of agency, which derives from the Latin ''agere'' (to do): an agreement to act on one's behalf. Such "action on behal ...

, relying on temporary remote connections via

SSH The Secure Shell Protocol (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network. Its most notable applications are remote login and command-line execution. SSH applications are based on ...

Windows Remote Management WinRM (Windows Remote Management) is Microsoft's implementation of WS-Management in Windows which allows systems to access or exchange management information across a common network. Utilizing scripting objects or the built-in command-line tool, W ...

which allows

PowerShell PowerShell is a task automation and configuration management program from Microsoft, consisting of a command-line shell (computing), shell and the associated scripting language. Initially a Windows component only, known as Windows PowerShell, it ...

execution. The Ansible control node runs on most Unix-like systems that are able to run

Python Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (pro ...

, including Windows with

Windows Subsystem for Linux Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

installed.

System configuration A system configuration (SC) in systems engineering defines the computers, processes, and devices that compose the system and its boundary. More generally, the system configuration is the specific definition of the elements that define and/or prescri ...

is defined in part by using its own

declarative language In computer science, declarative programming is a programming paradigm—a style of building the structure and elements of computer programs—that expresses the logic of a computation without describing its control flow. Many languages that a ...

History

The term "

ansible An ansible is a category of fictional devices or technology capable of near-instantaneous or faster-than-light communication. It can send and receive messages to and from a corresponding device over any distance or obstacle whatsoever with no d ...

" was coined by

Ursula K. Le Guin Ursula Kroeber Le Guin (; October 21, 1929 – January 22, 2018) was an American author best known for her works of speculative fiction, including science fiction works set in her Hainish universe, and the '' Earthsea'' fantasy series. She was ...

in her 1966 novel ''

Rocannon's World ''Rocannon's World'' is a science fiction novel by American writer Ursula K. Le Guin, her literary debut. It was published in 1966 as an Ace Double, along with Avram Davidson's ''The Kar-Chee Reign'', following the tête-bêche format. Though it i ...

'', and refers to fictional instantaneous communication systems. The Ansible tool was developed by Michael DeHaan, the author of the provisioning server application

Cobbler Cobbler(s) may refer to: *A person who Shoemaking, repairs, and sometimes makes, shoes Places * The Cobbler, a mountain located near the head of Loch Long in Scotland * Mount Cobbler, Australia Art, entertainment and media * The Cobbler (1923 ...

and co-author of the Fedora Unified Network Controller (Func) framework for remote administration. Ansible, Inc. (originally AnsibleWorks, Inc.) was the company founded in 2013 by DeHaan, Timothy Gerla, and Saïd Ziouani to commercially support and sponsor Ansible.

acquired Ansible in October 2015. Ansible is included as part of the

Fedora A fedora () is a hat with a soft brim and indented crown.Kilgour, Ruth Edwards (1958). ''A Pageant of Hats Ancient and Modern''. R. M. McBride Company. It is typically creased lengthwise down the crown and "pinched" near the front on both sides ...

distribution of Linux, owned by

, and is also available for

Red Hat Enterprise Linux Red Hat Enterprise Linux (RHEL) is a commercial open-source Linux distribution developed by Red Hat for the commercial market. Red Hat Enterprise Linux is released in server versions for x86-64, Power ISA, ARM64, and IBM Z and a desktop version ...

CentOS CentOS (, from Community Enterprise Operating System; also known as CentOS Linux) is a Linux distribution that provides a free and open-source community-supported computing platform, functionally compatible with its upstream source, Red Hat En ...

openSUSE openSUSE () is a free and open-source software, free and open source RPM Package Manager, RPM-based Linux distribution developed by the openSUSE project. The initial release of the community project was a beta version of SUSE Linux 10.0. Addi ...

SUSE Linux Enterprise SUSE Linux Enterprise (often abbreviated to SLE) is a Linux-based operating system developed by SUSE. It is available in two editions, suffixed with Server (SLES) for servers and mainframes, and Desktop (SLED) for workstations and desktop comp ...

Debian Debian (), also known as Debian GNU/Linux, is a Linux distribution composed of free and open-source software, developed by the community-supported Debian Project, which was established by Ian Murdock on August 16, 1993. The first version of D ...

Ubuntu Ubuntu ( ) is a Linux distribution based on Debian and composed mostly of free and open-source software. Ubuntu is officially released in three editions: ''Desktop'', ''Server'', and ''Core'' for Internet of things devices and robots. All the ...

Scientific Linux Scientific Linux (SL) was a Linux distribution produced by Fermilab, CERN, DESY and by ETH Zurich. It is a free and open-source operating system based on Red Hat Enterprise Linux. This product is derived from the free and open-source software ma ...

, and

Oracle Linux Oracle Linux (abbreviated OL, formerly known as Oracle Enterprise Linux or OEL) is a Linux distribution packaged and freely distributed by Oracle, available partially under the GNU General Public License since late 2006. It is compiled from Red ...

via Extra Packages for Enterprise Linux, as well as for other operating systems.

Architecture

Overview

Ansible helps to manage multiple machines by selecting portions of Ansible's

inventory Inventory (American English) or stock (British English) refers to the goods and materials that a business holds for the ultimate goal of resale, production or utilisation. Inventory management is a discipline primarily about specifying the shap ...

stored in simple

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...

text files. The inventory is configurable, and target machine inventory can be sourced dynamically or from cloud-based sources in different formats (

YAML YAML ( and ) (''see '') is a human-readable data-serialization language. It is commonly used for configuration files and in applications where data is being stored or transmitted. YAML targets many of the same communications applications as Exte ...

, INI). Sensitive data can be stored in encrypted files using Ansible Vault since 2014. In contrast with other popular configuration-management software — such as

Progress Chef Progress Chef (formerly Chef) is a configuration management tool written in Ruby and Erlang. It uses a pure-Ruby, domain-specific language (DSL) for writing system configuration "recipes". Chef is used to streamline the task of configuring ...

Puppet A puppet is an object, often resembling a human, animal or Legendary creature, mythical figure, that is animated or manipulated by a person called a puppeteer. The puppeteer uses movements of their hands, arms, or control devices such as rods ...

Salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

and

CFEngine CFEngine is an open-source configuration management system, written by Mark Burgess. Its primary function is to provide automated configuration and maintenance of large-scale computer systems, including the unified management of servers, desk ...

— Ansible uses an ''agentless'' architecture, with Ansible software not normally running or even installed on the controlled node. Instead, Ansible orchestrates a node by installing and running modules on the node temporarily via SSH. For the duration of an orchestration task, a process running the module communicates with the controlling machine with a

JSON JSON (JavaScript Object Notation, pronounced ; also ) is an open standard file format and data interchange format that uses human-readable text to store and transmit data objects consisting of attribute–value pairs and arrays (or other ser ...

-based protocol via its standard input and output. When Ansible is not managing a node, it does not consume resources on the node because no daemons are run or software installed.

Dependencies

Ansible requires

to be installed on all managing machines, including pip package manager along with configuration-management software and its dependent packages. Managed network devices require no extra dependencies and are agentless.

Control node

The control node (master host) is intended to manage (orchestrate) target machines (nodes termed as "

", see below). Control nodes are only available for

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...

and the like;

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

OSs are not supported. Multiple control nodes are allowed. Ansible does not require a single controlling machine for orchestration, ensuring that disaster recovery is simple. Nodes are managed by the controlling node over

Design goals

The design goals of Ansible include: * Minimal in nature. Management systems should not impose additional dependencies on the environment. * Consistent. With Ansible, one should be able to create consistent environments. * Secure. Ansible does not deploy agents to nodes. Only

OpenSSH OpenSSH (also known as OpenBSD Secure Shell) is a suite of secure networking utilities based on the Secure Shell (SSH) protocol, which provides a secure channel over an unsecured network in a client–server architecture. Network Working Gr ...

and Python are required on the managed nodes. * Reliable. When carefully written, an Ansible

playbook Playbook may refer to: * BlackBerry PlayBook, a tablet computer by BlackBerry *A book that contains a script or story for a theatrical play. This written version of the composition is used in preparing for a performance **Fleury Playbook, a medieva ...

can be

idempotent Idempotence (, ) is the property of certain operation (mathematics), operations in mathematics and computer science whereby they can be applied multiple times without changing the result beyond the initial application. The concept of idempotence ...

, to prevent unexpected side effects on the managed systems. It is possible to write playbooks that are not idempotent. * Minimal learning required. Playbooks use an easy and descriptive language based on YAML and Jinja templates.

Modules

Modules are mostly standalone and can be written in a standard scripting language (such as Python,

Perl Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offici ...

Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sa ...

, Bash, etc.). One of the guiding goals of modules is idempotency, which means that even if an operation is repeated multiple times (e.g., upon recovery from an outage), it will always place the system into the same state.

Inventory configuration

Location of target nodes is specified through inventory configuration lists (INI or YAML formatted) located at (on Linux). The configuration file lists either the

IP address An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...

hostname In computer networking, a hostname (archaically nodename) is a label that is assigned to a device connected to a computer network and that is used to identify the device in various forms of electronic communication, such as the World Wide Web. Hos ...

of each node that is accessible by Ansible. In addition, nodes can be assigned to groups. An example inventory (INI format): 192.168.6.1 ebserversfoo.example.com bar.example.com This configuration file specifies three nodes: the first node is specified by an IP address, and the latter two nodes are specified by hostnames. Additionally, the latter two nodes are grouped under the webservers group. Ansible can also use a custom ''Dynamic Inventory'' script, which can dynamically pull data from a different system, and supports groups of groups.

Playbooks

Playbooks are

files that store lists of tasks for repeated executions on managed nodes. Each Playbook maps (associates) a group of hosts to a set of roles. Each role is represented by calls to Ansible tasks.

Ansible Automation Platform

The Ansible Automation Platform (APP) is a REST API, web service, and web-based interface (application) designed to make Ansible more accessible to people with a wide range of IT skillsets. It is a platform composed of multiple components including developer tooling, an operations interface, as well as an Automation Mesh to enable automation tasks at scale across data centers. AAP is a commercial product supported by Red Hat, Inc. but derived 17+

upstream Upstream may refer to: * Upstream (bioprocess) * ''Upstream'' (film), a 1927 film by John Ford * Upstream (networking) * ''Upstream'' (newspaper), a newspaper covering the oil and gas industry * Upstream (petroleum industry) * Upstream (software ...

open source projects including the AWX upstream project (formerly Ansible Tower derived from), which has been open source since September 2017. There was also another open source alternative to Tower, ''Semaphore'', written in Go.

Platform support

Control machines have to be a Linux/Unix host (for example

BSD The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berk ...

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...

), and Python 2.7 or 3.5 is required. Managed nodes, if they are Unix-like, must have Python 2.4 or later. For managed nodes with Python 2.5 or earlier, the python-simplejson package is also required. Since version 1.7, Ansible can also manage Windows nodes. In this case, native PowerShell remoting supported by the WS-Management protocol is used instead of SSH. Ansible can deploy to

bare metal In computer science, bare machine (or bare metal) refers to a computer executing instructions directly on logic hardware without an intervening operating system. Modern operating systems evolved through various stages, from elementary to the pre ...

hosts,

virtual machines In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hard ...

, and cloud environments.

AnsibleFest

AnsibleFest is an annual conference of the Ansible community of users, contributors, etc.

References

External links

* {{Authority control Free software programmed in Python Configuration management Orchestration software Remote administration software Software distribution Software using the GPL license