Ansible is an agentless automation tool that you install on a control node. From the control node, Ansible manages machines and other devices remotely (by default, over the SSH protocol).
To install Ansible for use at the command line, simply install the Ansible package on one machine (which could easily be a laptop). You do not need to install a database or run any daemons. Ansible can manage an entire fleet of remote machines from that one control node.
Before you install Ansible, review the requirements for a control node. Before you use Ansible, review the requirements for managed nodes (those end devices you want to automate). Control nodes and managed nodes have different minimum requirements.
Windows is not supported for the control node, read more about this in `Matt Davis's blog post <http://blog.rolpdog.com/2020/03/why-no-ansible-controller-for-windows.html>`_.
Please note that some plugins that run on the control node have additional requirements. These requirements should be listed in the plugin documentation.
When choosing a control node, remember that any management system benefits from being run near the machines being managed. If you are using Ansible to manage machines in a cloud, consider using a machine inside that cloud as your control node. In most cases Ansible will perform better from a machine on the cloud than from a machine on the open Internet.
Ansible 2.11 will make Python 3.8 a soft dependency for the control node, but will function with the aforementioned requirements. Ansible 2.12 will require Python 3.8 or newer to function on the control node. Starting with Ansible 2.11, the project will only be packaged for Python 3.8 and newer.
Although you do not need a daemon on your managed nodes, you do need a way for Ansible to communicate with them. For most managed nodes, Ansible makes a connection over SSH and transfers modules using SFTP. If SSH works but SFTP is not available on some of your managed nodes, you can switch to SCP in :ref:`ansible.cfg <ansible_configuration_settings>`. For any machine or device that can run Python, you also need Python 2 (version 2.6 or later) or Python 3 (version 3.5 or later).
..warning::
Please note that some modules have additional requirements that need to be satisfied on the 'target' machine (the managed node). These requirements should be listed in the module documentation.
* If you have SELinux enabled on remote nodes, you will also want to install libselinux-python on them before using any copy/file/template related functions in Ansible. You can use the :ref:`yum module<yum_module>` or :ref:`dnf module<dnf_module>` in Ansible to install this package on remote systems that do not have it.
* By default, before the first Python module in a playbook runs on a host, Ansible attempts to discover a suitable Python interpreter on that host. You can override the discovery behavior by setting the :ref:`ansible_python_interpreter<ansible_python_interpreter>` inventory variable to a specific interpreter, and in other ways. See :ref:`interpreter_discovery` for details.
* Ansible's :ref:`raw module<raw_module>`, and the :ref:`script module<script_module>`, do not depend on a client side install of Python to run. Technically, you can use Ansible to install a compatible version of Python using the :ref:`raw module<raw_module>`, which then allows you to use everything else. For example, if you need to bootstrap Python 2 onto a RHEL-based system, you can install it as follows:
Starting with version 2.10, Ansible distributes two artifacts: a community package called ``ansible`` and a minimalist language and runtime called ``ansible-core`` (called `ansible-base` in version 2.10). Choose the Ansible artifact and version that matches your particular needs.
The ``ansible`` package includes the Ansible language and runtime plus a range of community curated Collections. It recreates and expands on the functionality that was included in Ansible 2.9.
You can choose any of the following ways to install the Ansible community package:
Ansible also distributes a minimalist object called ``ansible-core`` (or ``ansible-base`` in version 2.10). It contains the Ansible language, runtime, and a short list of core modules and other plugins. You can build functionality on top of ``ansible-core`` by installing collections from Galaxy, Automation Hub, or any other source.
You can choose any of the following ways to install ``ansible-core``:
* Install ``ansible-core`` (version 2.11 and greater) or ``ansible-base`` (version 2.10) with ``pip``.
* Install ``ansible-core`` from source from the ansible/ansible GitHub repository to access the development (``devel``) version to develop or test the latest features.
You should only run ``ansible-core`` from ``devel`` if you are modifying ``ansible-core``, or trying out features under development. This is a rapidly changing source of code and can become unstable at any point.
Ansible generally creates new releases twice a year. See :ref:`release_and_maintenance` for information on release timing and maintenance of older releases.
You may need to perform some additional configuration before you are able to run Ansible. See the Python documentation on `installing to the user site`_ for more information.
.._installing to the user site: https://packaging.python.org/tutorials/installing-packages/#installing-to-the-user-site
If you wish to install Ansible globally, run the following commands::
$ sudo python get-pip.py
$ sudo python -m pip install ansible
..note::
Running ``pip`` with ``sudo`` will make global changes to the system. Since ``pip`` does not coordinate with system package managers, it could make changes to your system that leaves it in an inconsistent or non-functioning state. This is particularly true for macOS. Installing with ``--user`` is recommended unless you understand fully the implications of modifying global files on the system.
..note::
Older versions of ``pip`` default to http://pypi.python.org/simple, which no longer works.
Please make sure you have the latest version of ``pip`` before installing Ansible.
If you have an older version of ``pip`` installed, you can upgrade by following `pip's upgrade instructions <https://pip.pypa.io/en/stable/installing/#upgrading-pip>`_ .
.._from_pip_venv:
Installing Ansible in a virtual environment with ``pip``
Ansible can also be installed inside a new or existing ``virtualenv``::
$ python -m virtualenv ansible # Create a virtualenv if one does not already exist
$ source ansible/bin/activate # Activate the virtual environment
$ python -m pip install ansible
.._pip_upgrade:
Upgrading Ansible with ``pip``
------------------------------
Upgrading from 2.9 or earlier to 2.10
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Starting in version 2.10, Ansible is made of two packages. When you upgrade from version 2.9 and older to version 2.10 or later, you need to uninstall the old Ansible version (2.9 or earlier) before upgrading. If you do not uninstall the older version of Ansible, you will see the following message, and no change will be performed:
..code-block:: console
Cannot install ansible-base with a pre-existing ansible==2.x installation.
Installing ansible-base with ansible-2.9 or older currently installed with
pip is known to cause problems. Please uninstall ansible and install the new
version:
pip uninstall ansible
pip install ansible-base
...
As explained by the message, to upgrade you must first remove the version of Ansible installed and then install it to the latest version.
``ansible-base`` only exists for version 2.10 and in Ansible 3. In 2.11 and later, the package is called ``ansible-core``. Before installing ``ansible-core`` or Ansible 4, you must uninstall ``ansible-base`` if you have installed Ansible 3 or ``ansible-base`` 2.10.
..note:: On older Ubuntu distributions, "software-properties-common" is called "python-software-properties". You may want to use ``apt-get`` instead of ``apt`` in older versions. Also, be aware that only newer distributions (in other words, 18.04, 18.10, and so on) have a ``-u`` or ``--update`` flag, so adjust your script accordingly.
The instructions can be found in :ref:`from_pip`. If you are running macOS version 10.12 or older, then you should upgrade to the latest ``pip`` to connect to the Python Package Index securely. It should be noted that pip must be run as a module on macOS, and the linked ``pip`` instructions will show you how to do that.
macOS by default is configured for a small number of file handles, so if you want to use 15 or more forks you'll need to raise the ulimit with ``sudo launchctl limit maxfiles unlimited``. This command can also fix any "Too many open files" errors.
In Ansible 2.10 and later, the `ansible/ansible repository <https://github.com/ansible/ansible>`_ contains the code for basic features and functions, such as copying module code to managed nodes. This code is also known as ``ansible-core``.
New features are added to ``ansible-core`` on a branch called ``devel``. If you are testing new features, fixing bugs, or otherwise working with the development team on changes to the core code, you can install and run ``devel``.
You should only install and run the ``devel`` branch if you are modifying ``ansible-core`` or trying out features under development. This is a rapidly changing source of code and can become unstable at any point.
If you want to use Ansible AWX as the control node, do not install or run the ``devel`` branch of Ansible. Use an OS package manager (like ``apt`` or ``yum``) or ``pip`` to install a stable version.
If you are running Ansible from source, you may also wish to follow the `Ansible GitHub project <https://github.com/ansible/ansible>`_. We track issues, document bugs, and share feature ideas in this and other related repositories.
For more information on getting involved in the Ansible project, see the :ref:`ansible_community_guide`. For more information on creating Ansible modules and Collections, see the :ref:`developer_guide`.
You can replace ``devel`` in the URL mentioned above, with any other branch or tag on GitHub to install older versions of Ansible (prior to ``ansible-base`` 2.10.), tagged alpha or beta versions, and release candidates. This installs all of Ansible.
``ansible-core`` is easy to run from source. You do not need ``root`` permissions to use it and there is no software to actually install. No daemons or database setup are required.
After you run the the env-setup script, you will be running from the source code. The default inventory file will be ``/etc/ansible/hosts``. You can optionally specify an inventory file (see :ref:`inventory`) other than ``/etc/ansible/hosts``:
If you are packaging Ansible or wanting to build a local package yourself, and you want to avoid a git checkout, you can use a tarball of a tagged release. You can download the latest stable release from PyPI's `ansible package page <https://pypi.org/project/ansible/>`_. If you need a specific older version, beta version, or release candidate, you can use the pattern ``pypi.python.org/packages/source/a/ansible/ansible-{{VERSION}}.tar.gz``. VERSION must be the full version number, for example 3.1.0 or 4.0.0b2. You can make VERSION a variable in your package managing system that you update in one place whenever you package a new version.
If you are creating your own Ansible package, you must also download or package ``ansible-core`` (or ``ansible-base`` for packages based on 2.10.x) from PyPI as part of your Ansible package. You must specify a particular version. Visit the PyPI project pages to download files for `ansible-core <https://pypi.org/project/ansible-core/>`_ or `ansible-base <https://pypi.org/project/ansible-base/>`_.
As of Ansible 2.9, you can add shell completion of the Ansible command line utilities by installing an optional dependency called ``argcomplete``. ``argcomplete`` supports bash, and has limited support for zsh and tcsh.
You can install ``python-argcomplete`` from EPEL on Red Hat Enterprise based distributions, and or from the standard OS repositories for many other distributions.
