This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)(Learn how and when to remove this template message)
|Original author(s)||Michael DeHaan|
|Developer(s)||Ansible Community / Ansible Inc. / Red Hat Inc.|
|Initial release||February 20, 2012|
|Written in||Python, PowerShell|
|Operating system||Linux, Unix-like, Windows|
|Type||Configuration management, Infrastructure as Code, Orchestration engine|
|License||GNU General Public License|
Michael DeHaan, the author of the provisioning server application Cobbler and co-author of the Func framework for remote administration, developed the platform. It is included as part of the Fedora distribution of Linux, owned by Red Hat Inc., and is also available for Red Hat Enterprise Linux, CentOS, and Scientific Linux via Extra Packages for Enterprise Linux (EPEL) as well as for other operating systems.
The name "Ansible" references a fictional instantaneous hyperspace communication system (as featured in Orson Scott Card's Ender's Game (1985), and originally invented by Ursula K. Le Guin for her novel Rocannon's World (1966)).
As with most configuration management software, Ansible has two types of servers: controlling machines and nodes. First, there is a single controlling machine which is where orchestration begins. Nodes are managed by a controlling machine over SSH. The controlling machine describes the location of nodes through its inventory.
To orchestrate nodes, Ansible deploys modules to nodes over SSH. Modules are temporarily stored in the nodes and communicate with the controlling machine through a JSON protocol over the standard output. When Ansible is not managing nodes, it does not consume resources because no daemons or programs are executing for Ansible in the background.
In contrast with popular configuration management software — such as Chef, Puppet, and CFEngine — Ansible uses an agentless architecture. With an agent-based architecture, nodes must have a locally installed daemon that communicates with a controlling machine. With an agentless architecture, nodes are not required to install and run background daemons to connect with a controlling machine. This type of architecture reduces the overhead on the network by preventing the nodes from polling the controlling machine.
The design goals of Ansible include:
- Minimal in nature. Management systems should not impose additional dependencies on the environment.
- Consistent.[clarification needed]
- Secure. Ansible does not deploy agents to nodes. Only OpenSSH is required.
- Highly reliable. When carefully written, an Ansible playbook can be idempotent, in order to prevent unexpected side-effects on the managed systems. It should be noted, however, that it is entirely possible to have a poorly written playbook that is not idempotent.
- Low learning curve. Playbooks use an easy and descriptive language based on YAML and Jinja templates.
Modules are considered to be the units of work in Ansible. Each module is mostly standalone and can be written in a standard scripting language (such as Python, Perl, Ruby, Bash, etc.). One of the guiding properties 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.
The Inventory is a description of the nodes that can be accessed by Ansible. By default, the Inventory is described by a configuration file, in INI format, whose default location is in
/etc/ansible/hosts. The configuration file lists either the IP address or hostname of each node that is accessible by Ansible. In addition, nodes can be assigned to groups.
An example inventory:
192.168.6.1 [webservers] foo.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
Ansible can also use a custom Dynamic Inventory script, which can dynamically pull data from a different system.
Playbooks express configurations, deployment, and orchestration in Ansible. The Playbook format is YAML. Each Playbook maps a group of hosts to a set of roles. Each role is represented by calls to Ansible tasks.
Ansible Tower is an API, web service, and web-based console designed to make Ansible usable for IT teams. It is a hub for automation tasks. Tower is a commercial product supported by Red Hat, Inc. One may register for updates in releasing Tower as Open Source Software.
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 is used, instead of SSH.
Apart from bare metal hosts, ansible can deploy to virtualization and cloud environments, including Amazon Web Services, CloudStack, DigitalOcean, Eucalyptus Cloud, Google Cloud Platform, KVM, Microsoft Azure, OpenStack, Rackspace, SoftLayer, VMware, and XenServer.
- Comparison of open-source configuration management software
- Infrastructure as Code
- Ansible 18.104.22.168 on Python Package Index
- Ansible 22.214.171.124 on ansible.com
- "How Ansible Works | Ansible.com". Ansible.com. Retrieved 7 December 2016.
- Mike Maughan (April 17, 2012). "An Interview with Ansible Author Michael DeHaan". coloandcloud.com. Maughansem LLC. p. 1. Retrieved November 5, 2012.
- Mykola Ulianytskyi. "ansible Download (DEB, RPM, TGZ, TXZ, XZ)". pkgs.org. Linux Packages Search. p. 1. Retrieved November 5, 2012.
- "About Ansible". Ansible, Inc. p. 1. Archived from the original on September 5, 2015. Retrieved July 8, 2016.
- Bloomberg Research. "Ansible, Inc.: Private Company Information". Internet Software and Services. Bloomberg L.P. p. 1. Retrieved July 8, 2016.
- Jordan Novet (October 15, 2015). "Source: Red Hat is buying Ansible for more than $100M". venturebeat.com. VentureBeat, Inc. p. 1. Retrieved October 16, 2015.
- "Red Hat to Acquire IT Automation and DevOps Leader Ansible". redhat.com. October 16, 2015. Retrieved October 16, 2015.
- Ansible Community. "Frequently Asked Questions". docs.ansible.com. Ansible Documentation. Red Hat, Inc. p. 1. Retrieved April 30, 2013.
- Ansible Community. "Inventory". docs.ansible.com. Ansible Documentation. Red Hat, Inc. p. 1. Retrieved April 26, 2014.
- "Ansible in Depth" (PDF).
- "The Benefits of Agentless Architecture" (PDF). Red Hat, Inc. p. 5.
- "Achieving Rolling Updates and Continuous Deployment with Zero Downtime" (PDF). Red Hat, Inc. p. 7.
- Ansible Community. "Dynamic Inventory". docs.ansible.com. Ansible Documentation. Red Hat, Inc. p. 1. Retrieved November 25, 2016.
- Ansible Community. "Playbooks". docs.ansible.com. Ansible Documentation. Red Hat, Inc. p. 1. Retrieved April 26, 2014.
- Ansible Community. "Task And Handler Organization For A Role". docs.ansible.com. Ansible Documentation. Red Hat, Inc. p. 1. Retrieved November 25, 2016.
- Ansible Community. "Getting started". docs.ansible.com. Ansible Documentation. Red Hat, Inc. p. 1. Retrieved February 6, 2014.
- "Ansible 1.7 is released - Windows beta and more!". August 7, 2014.