mirror of
https://github.com/ansible-collections/community.general.git
synced 2024-09-14 20:13:21 +02:00
215 lines
5.6 KiB
ReStructuredText
215 lines
5.6 KiB
ReStructuredText
.. _patterns:
|
|
|
|
Inventory & Patterns
|
|
====================
|
|
|
|
Ansible works against multiple systems in your infrastructure at the
|
|
same time. It does this by selecting portions of systems listed in
|
|
Ansible's inventory file, which defaults to /etc/ansible/hosts.
|
|
|
|
.. contents:: `Table of contents`
|
|
:depth: 2
|
|
:backlinks: top
|
|
|
|
.. _inventoryformat:
|
|
|
|
Hosts and Groups
|
|
++++++++++++++++
|
|
|
|
The format for /etc/ansible/hosts is an INI format and looks like this::
|
|
|
|
mail.example.com
|
|
|
|
[webservers]
|
|
foo.example.com
|
|
bar.example.com
|
|
|
|
[dbservers]
|
|
one.example.com
|
|
two.example.com
|
|
three.example.com
|
|
|
|
The things in brackets are group names. You don't have to have them,
|
|
but they are useful.
|
|
|
|
If you have hosts that run on non-standard SSH ports you can put the port number
|
|
after the hostname with a colon.
|
|
|
|
four.example.com:5309
|
|
|
|
In 0.6 and later, if you have a lot of hosts following similar patterns you can do this rather than listing each hostname::
|
|
|
|
[webservers]
|
|
www[01:50].example.com
|
|
|
|
Leading zeros can be included or removed, as desired, and the ranges are inclusive.
|
|
|
|
Selecting Targets
|
|
+++++++++++++++++
|
|
|
|
We'll go over how to use the command line in :doc:`examples` section, however, basically it looks like this::
|
|
|
|
ansible <pattern_goes_here> -m <module_name> -a <arguments>
|
|
|
|
Such as::
|
|
|
|
ansible webservers -m service -a "name=httpd state=restarted"
|
|
|
|
Within :doc:`playbooks`, these patterns can be used for even greater purposes.
|
|
|
|
Anyway, to use Ansible, you'll first need to know how to tell Ansible which hosts in your inventory file to talk to.
|
|
This is done by designating particular host names or groups of hosts.
|
|
|
|
The following patterns target all hosts in the inventory file::
|
|
|
|
all
|
|
*
|
|
|
|
Basically 'all' is an alias for '*'. It is also possible to address a specific host or hosts::
|
|
|
|
one.example.com
|
|
one.example.com:two.example.com
|
|
192.168.1.50
|
|
192.168.1.*
|
|
|
|
The following patterns address one or more groups, which are denoted
|
|
with the aforementioned bracket headers in the inventory file::
|
|
|
|
webservers
|
|
webservers:dbservers
|
|
|
|
You can exclude groups as well, for instance, all webservers not in Phoenix::
|
|
|
|
webservers:!phoenix
|
|
|
|
Individual host names (or IPs), but not groups, can also be referenced using
|
|
wildcards::
|
|
|
|
*.example.com
|
|
*.com
|
|
|
|
It's also ok to mix wildcard patterns and groups at the same time::
|
|
|
|
one*.com:dbservers
|
|
|
|
Easy enough. See :doc:`examples` and then :doc:`playbooks` for how to do things to selected hosts.
|
|
|
|
Host Variables
|
|
++++++++++++++
|
|
|
|
It is easy to assign variables to hosts that will be used later in playbooks::
|
|
|
|
[atlanta]
|
|
host1 http_port=80 maxRequestsPerChild=808
|
|
host2 http_port=303 maxRequestsPerChild=909
|
|
|
|
|
|
Group Variables
|
|
+++++++++++++++
|
|
|
|
Variables can also be applied to an entire group at once::
|
|
|
|
[atlanta]
|
|
host1
|
|
host2
|
|
|
|
[atlanta:vars]
|
|
ntp_server=ntp.atlanta.example.com
|
|
proxy=proxy.atlanta.example.com
|
|
|
|
Groups of Groups, and Group Variables
|
|
+++++++++++++++++++++++++++++++++++++
|
|
|
|
It is also possible to make groups of groups and assign
|
|
variables to groups. These variables can be used by /usr/bin/ansible-playbook, but not
|
|
/usr/bin/ansible::
|
|
|
|
[atlanta]
|
|
host1
|
|
host2
|
|
|
|
[raleigh]
|
|
host2
|
|
host3
|
|
|
|
[southeast:children]
|
|
atlanta
|
|
raleigh
|
|
|
|
[southeast:vars]
|
|
some_server=foo.southeast.example.com
|
|
halon_system_timeout=30
|
|
self_destruct_countdown=60
|
|
escape_pods=2
|
|
|
|
[usa:children]
|
|
southeast
|
|
northeast
|
|
southwest
|
|
southeast
|
|
|
|
If you need to store lists or hash data, or prefer to keep host and group specific variables
|
|
seperate from the inventory file, see the next section.
|
|
|
|
Splitting Out Host and Group Specific Data
|
|
++++++++++++++++++++++++++++++++++++++++++
|
|
|
|
.. versionadded:: 0.6
|
|
|
|
In addition to the storing variables directly in the INI file, host
|
|
and group variables can be stored in individual files relative to the
|
|
inventory file. These variable files are in YAML format.
|
|
|
|
Assuming the inventory file path is::
|
|
|
|
/etc/ansible/hosts
|
|
|
|
If the host is named 'foosball', and in groups 'raleigh' and 'webservers', variables
|
|
in YAML files at the following locations will be made available to the host::
|
|
|
|
/etc/ansible/group_vars/raleigh
|
|
/etc/ansible/group_vars/webservers
|
|
/etc/ansible/host_vars/foosball
|
|
|
|
For instance, suppose you have hosts grouped by datacenter, and each datacenter
|
|
uses some different servers. The data in the groupfile '/etc/ansible/group_vars/raleigh' for
|
|
the 'raleigh' group might look like::
|
|
|
|
---
|
|
ntp_server: acme.example.org
|
|
database_server: storage.example.org
|
|
|
|
It is ok if these files do not exist, this is an optional feature.
|
|
|
|
Tip: Keeping your inventory file and variables in a git repo (or other version control)
|
|
is an excellent way to track changes to your inventory and host variables.
|
|
|
|
.. versionadded:: 0.5
|
|
If you ever have two python interpreters on a system, set a
|
|
variable called 'ansible_python_interpreter' to the Python
|
|
interpreter path you would like to use.
|
|
|
|
YAML Inventory
|
|
++++++++++++++
|
|
|
|
.. deprecated:: 0.7
|
|
|
|
Ansible's YAML inventory format is deprecated and will be removed in
|
|
Ansible 0.7. Ansible 0.6 includes a `conversion script
|
|
<https://github.com/ansible/ansible/blob/devel/examples/scripts/yaml_to_ini.py>`_.
|
|
|
|
Usage::
|
|
|
|
yaml_to_ini.py /etc/ansible/hosts
|
|
|
|
.. seealso::
|
|
|
|
:doc:`examples`
|
|
Examples of basic commands
|
|
:doc:`playbooks`
|
|
Learning ansible's configuration management language
|
|
`Mailing List <http://groups.google.com/group/ansible-project>`_
|
|
Questions? Help? Ideas? Stop by the list on Google Groups
|
|
`irc.freenode.net <http://irc.freenode.net>`_
|
|
#ansible IRC chat channel
|
|
|