Ansible is a suite of software tools that enables infrastructure as code. It is

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

and the suite includes software

provisioning Provisioning may refer to: * Provisioning (technology), the equipping of a telecommunications network or IT resources * Provisioning (cruise ship), supplying a vessel for an extended voyage ** Provisioning of USS ''Constitution'' * Provisionin ...

configuration management Configuration management (CM) is a management 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. ...

, and application deployment functionality. Originally written by Michael DeHaan in 2012, and acquired by

Red Hat Red Hat, Inc. (formerly Red Hat Software, Inc.) is an American software company that provides open source software products to enterprises and is a subsidiary of IBM. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North ...

in 2015, Ansible is designed to configure both

Unix-like A Unix-like (sometimes referred to as UN*X, *nix 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 Uni ...

systems and

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

. Ansible is agentless, relying on temporary remote connections via

SSH The Secure Shell Protocol (SSH Protocol) 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 was designed for Un ...

Windows Remote Management Windows Remote Management (WinRM) is the Microsoft implementation of the DMTF-standard WS-Management. It allows accessing or exchanging management information across a common network. Utilizing scripting objects or the built-in command-line tool, ...

which allows

PowerShell PowerShell is a shell program developed by Microsoft for task automation and configuration management. As is typical for a shell, it provides a command-line interpreter for interactive use and a script interpreter for automation via a langu ...

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 (prog ...

, including Windows with

Windows Subsystem for Linux Windows Subsystem for Linux (WSL) is a component of Microsoft Windows that allows the use of a GNU/Linux environment from within Windows, foregoing the overhead of a virtual machine and being an alternative to dual booting. The WSL command-lin ...

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 presc ...

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 app ...

History

The term "

ansible The term ''ansible'' refers to a category of fictional technological devices capable of superluminal Faster-than-light (superluminal or supercausal) travel and communication are the conjectural propagation of matter or information faster than ...

" was coined by

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

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. Published in 1966, it appeared as an Ace Double, with an opening entitled "Semley's Necklace" that first appeared as the stand-alone stor ...

'', 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 repairs shoes * Cobbler (food), a type of pie Places * The Cobbler, a mountain located near the head of Loch Long in Scotland * Mount Cobbler, Australia Art, entertainment and media * ''The Cobbler' ...

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 Linux distribution developed by Red Hat. Red Hat Enterprise Linux is released in server versions for x86-64, Power ISA, ARM64, and IBM Z and a desktop version for x86-64. Fedora Linux and ...

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

openSUSE openSUSE () is a free and open-source software, free and open-source Linux distribution developed by the openSUSE project. It is offered in two main variations: ''Tumbleweed'', an upstream rolling release distribution, and ''Leap'', a stable r ...

SUSE Linux Enterprise SUSE Linux Enterprise (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 computers. Its major ve ...

Debian Debian () is a free and open-source software, free and open source Linux distribution, developed by the Debian Project, which was established by Ian Murdock in August 1993. Debian is one of the oldest operating systems based on the Linux kerne ...

Ubuntu Ubuntu ( ) is a Linux distribution based on Debian and composed primarily of free and open-source software. Developed by the British company Canonical (company), Canonical and a community of contributors under a Meritocracy, meritocratic gover ...

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

, 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, in part, compile ...

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 (British English) or stock (American English) is a quantity of 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 ...

stored in simple

plain text In computing, plain text is a loose term for data (e.g. file contents) that represent only characters of readable material but not its graphical representation nor other objects ( floating-point numbers, images, etc.). It may also include a lim ...

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

YAML YAML ( ) 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 Extensible Marku ...

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

Chef A chef is a professional Cook (profession), cook and tradesperson who is proficient in all aspects of outline of food preparation, food preparation, often focusing on a particular cuisine. The word "chef" is derived from the term (), the di ...

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. Puppetry is an ancient form of theatre which dates back to the 5th century BC in anci ...

Salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

and

CFEngine CFEngine is a 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, desktops, consume ...

— 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 or ) is an open standard file format and electronic data interchange, data interchange format that uses Human-readable medium and data, human-readable text to store and transmit data objects consi ...

-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 can be run from

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

and

operating systems (including

MacOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

);

Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

OSs are only supported through the

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

playbook The BlackBerry PlayBook is a mini tablet computer that was developed by BlackBerry. It was manufactured by Quanta Computer, an original design manufacturer (ODM).

can be

idempotent Idempotence (, ) is the property of certain 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 arises in a number of pl ...

, 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 high-level, general-purpose, interpreted, dynamic programming language. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed ...

Ruby 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 sapph ...

, 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 assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface i ...

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 format ( INI file): 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 (AAP) is a

REST API REST (Representational State Transfer) is a software architectural style that was created to describe the design and guide the development of the architecture for the World Wide Web. REST defines a set of constraints for how the architecture of ...

web service A web service (WS) is either: * a service offered by an electronic device to another electronic device, communicating with each other via the Internet, or * a server running on a computer device, listening for requests at a particular port over a n ...

, 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 from 17+ upstream open source projects including the AWX upstream project (formerly Ansible Tower), which has been open source since September 2017. There also is 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 (BSD), also known as Berkeley Unix or BSD Unix, is a discontinued Unix operating system developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley, beginni ...

macOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

), 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 information technology, bare machine (or bare-metal computer) is a computer which has no operating system. The software executed by a bare machine, commonly called a "bare metal program" or "bare metal application", is designed to interact dir ...

hosts,

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

, and cloud environments.

References

External links

* {{Authority control Free software programmed in Python Configuration management Orchestration software Remote administration software Software distribution Software using the GNU General Public License