147 lines
4.3 KiB
ReStructuredText
147 lines
4.3 KiB
ReStructuredText
.. _patterns:
|
|
|
|
The Inventory File, Patterns, and Groups
|
|
========================================
|
|
|
|
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.
|
|
|
|
.. _inventoryformat:
|
|
|
|
Basic Inventory File Format
|
|
+++++++++++++++++++++++++++
|
|
|
|
The format for /etc/ansible/hosts 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. This requires Ansible 0.3 (integration branch)::
|
|
|
|
four.example.com:5309
|
|
|
|
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 also 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
|
|
|
|
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
|
|
|
|
.. note::
|
|
It is not possible to target a host not in the inventory file. This is a safety feature.
|
|
|
|
Easy enough. See :doc:`examples` and then :doc:`playbooks` for how to do things to selected hosts.
|
|
|
|
Advanced Inventory File Format
|
|
++++++++++++++++++++++++++++++
|
|
|
|
(This features requires the integration branch of Ansible, soon to be release 0.3)
|
|
|
|
Once you read about playbooks you'll quickly see how useful it will be to assign particular variables
|
|
to particular hosts and groups of hosts. While the default INI-style host format doesn't allow this,
|
|
switching to the YAML inventory format can add some compelling capabilities. Just replace your INI
|
|
style file with a YAML one.::
|
|
|
|
---
|
|
|
|
# some ungrouped hosts, either use the short string form or the "host: " prefix
|
|
- host: jupiter
|
|
- mars
|
|
|
|
# variables can be assigned like this...
|
|
- host: saturn
|
|
vars:
|
|
- moon: titan
|
|
|
|
# groups can also set variables to all hosts in the group
|
|
# here are a bunch of hosts using a non-standard SSH port
|
|
# and also defining a variable 'ntpserver'
|
|
- group: greek
|
|
hosts:
|
|
- zeus
|
|
- hera
|
|
- poseidon
|
|
vars:
|
|
- ansible_ssh_port: 3000
|
|
- ntp_server: olympus.example.com
|
|
|
|
# individual hosts can still set variables inside of groups too
|
|
# so you aren't limited to just group variables and host variables.
|
|
- group: norse
|
|
hosts:
|
|
- host: thor
|
|
vars:
|
|
- hammer: True
|
|
- odin
|
|
- loki
|
|
vars:
|
|
- asdf: 1234
|
|
|
|
Tip: Be sure to start your YAML file with the YAML record designator ``---``.
|
|
|
|
NOTE: variables specified in playbooks will override variables specified
|
|
in the host file. Further, if a host is in multiple groups, currently, the
|
|
variables set by the last loaded group will win over variables set in other
|
|
groups. This behavior may be refined in future releases.
|
|
|
|
.. 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
|
|
|