In the above example, trying to ansible against the host alias "jumper" (which may not even be a real hostname) will contact 192.168.1.50 on port 5555.
In the above example, trying to ansible against the host alias "jumper" (which may not even be a real hostname) will contact 192.168.1.50 on port 5555. Note that this is using a feature of the inventory file to define some special variables. Generally speaking this is not the best
way to define variables that describe your system policy, but we'll share suggestions on doing this later. We're just getting started.
Adding a lot of hosts? If you have a lot of hosts following similar patterns you can do this rather than listing each hostname::
Adding a lot of hosts? 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
In 1.0 and later, you can also do this for alphabetic ranges::
For numeric patterns, leading zeros can be included or removed, as desired. Ranges are inclusive. You can also define alphabetic ranges::
[databases]
db-[a:f].example.com
For numeric patterns, leading zeros can be included or removed, as desired. Ranges are inclusive.
In 1.1 and later, you can also select the connection type and user on a per host basis::
You can also select the connection type and user on a per host basis::
[targets]
...
...
@@ -64,121 +68,18 @@ In 1.1 and later, you can also select the connection type and user on a per host
All of these variables can of course also be set outside of the inventory file, in 'host_vars' if you wish
to keep your inventory file simple.
List of Reserved Inventory Parameters
+++++++++++++++++++++++++++++++++++++
As a summary, you can set these parameters as host inventory variables. (Some we have already
mentioned).
ansible_ssh_host
The name of the host to connect to, if different from the alias you wish to give to it.
ansible_ssh_port
The ssh port number, if not 22
ansible_ssh_user
The default ssh user name to use.
ansible_ssh_pass
The ssh password to use (this is insecure, we strongly recommend using --ask-pass or SSH keys)
ansible_connection
Connection type of the host. Candidates are local, ssh or paramiko. The default is paramiko before Ansible 1.2, and 'smart' afterwards which detects whether usage of 'ssh' would be feasible based on whether ControlPersist is supported.
ansible_ssh_private_key_file
Private key file used by ssh. Useful if using multiple keys and you don't want to use SSH agent.
ansible_syslog_facility
The syslog facility to log to.
ansible_python_interpreter
The target host python path. This is userful for systems with more
than one Python or not located at "/usr/bin/python" such as \*BSD, or where /usr/bin/python
is not a 2.X series Python.
ansible\_\*\_interpreter
Works for anything such as ruby or perl and works just like ansible_python_interpreter.
This replaces shebang of modules which will run on that host.
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
You can also specify the intersection of two groups::
webservers:&staging
You can do combinations::
webservers:dbservers:!phoenix:&staging
You can also use variables::
webservers:!{{excluded}}:&{{required}}
Individual host names, IPs and 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
And if the pattern starts with a '~' it is treated as a regular expression::
~(web|db).*\.example\.com
Easy enough. See :doc:`examples` and then :doc:`playbooks` for how to do things to selected hosts.
As mentioned above, setting these in the inventory file is only a shorthand, and we'll discuss how to store them in individual files
in the 'host_vars' directory a bit later on.
Host Variables
++++++++++++++
It is easy to assign variables to hosts that will be used later in playbooks::
As alluded to above, 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
+++++++++++++++
...
...
@@ -229,11 +130,13 @@ separate from the inventory file, see the next section.
Splitting Out Host and Group Specific Data
++++++++++++++++++++++++++++++++++++++++++
.. versionadded:: 0.6
The preferred practice in Ansible is actually not to store variables in the main inventory file.
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.
inventory file.
These variable files are in YAML format. See `YAMLSyntax` if you are new to YAML.
Assuming the inventory file path is::
...
...
@@ -254,7 +157,7 @@ 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.
It is ok if these files do not exist, as this is an optional feature.
Tip: In Ansible 1.2 or later the group_vars/ and host_vars/ directories can exist in either
the playbook directory OR the inventory directory. If both paths exist, variables in the playbook
...
...
@@ -263,14 +166,47 @@ directory will be loaded second.
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, or your Python version 2 interpreter is not found
at /usr/bin/python, set an inventory variable called 'ansible_python_interpreter' to the Python
interpreter path you would like to use.
List of Behavioral Inventory Parameters
+++++++++++++++++++++++++++++++++++++++
As aluded to above, setting the following variables controls how ansible interacts with remote hosts. Some we have already
mentioned::
ansible_ssh_host
The name of the host to connect to, if different from the alias you wish to give to it.
ansible_ssh_port
The ssh port number, if not 22
ansible_ssh_user
The default ssh user name to use.
ansible_ssh_pass
The ssh password to use (this is insecure, we strongly recommend using --ask-pass or SSH keys)
ansible_connection
Connection type of the host. Candidates are local, ssh or paramiko. The default is paramiko before Ansible 1.2, and 'smart' afterwards which detects whether usage of 'ssh' would be feasible based on whether ControlPersist is supported.
ansible_ssh_private_key_file
Private key file used by ssh. Useful if using multiple keys and you don't want to use SSH agent.
ansible_python_interpreter
The target host python path. This is userful for systems with more
than one Python or not located at "/usr/bin/python" such as \*BSD, or where /usr/bin/python
is not a 2.X series Python. We do not use the "/usr/bin/env" mechanism as that requires the remote user's
path to be set right and also assumes the "python" executable is named python, where the executable might
be named something like "python26".
ansible\_\*\_interpreter
Works for anything such as ruby or perl and works just like ansible_python_interpreter.
This replaces shebang of modules which will run on that host.
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::
:depth: 2
.. _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. Ports listed in any SSH config file won't be read,
so it is important that you set them if things are not running on the default port::
badwolf.example.com:5309
Suppose you have just static IPs and want to set up some aliases that don't live in your host file, or you are connecting through tunnels. You can do things like this::
In the above example, trying to ansible against the host alias "jumper" (which may not even be a real hostname) will contact 192.168.1.50 on port 5555.
Adding a lot of hosts? 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
In 1.0 and later, you can also do this for alphabetic ranges::
[databases]
db-[a:f].example.com
For numeric patterns, leading zeros can be included or removed, as desired. Ranges are inclusive.
In 1.1 and later, you can also select the connection type and user on a per host basis::
All of these variables can of course also be set outside of the inventory file, in 'host_vars' if you wish
to keep your inventory file simple.
List of Reserved Inventory Parameters
+++++++++++++++++++++++++++++++++++++
As a summary, you can set these parameters as host inventory variables. (Some we have already
mentioned).
ansible_ssh_host
The name of the host to connect to, if different from the alias you wish to give to it.
ansible_ssh_port
The ssh port number, if not 22
ansible_ssh_user
The default ssh user name to use.
ansible_ssh_pass
The ssh password to use (this is insecure, we strongly recommend using --ask-pass or SSH keys)
ansible_connection
Connection type of the host. Candidates are local, ssh or paramiko. The default is paramiko before Ansible 1.2, and 'smart' afterwards which detects whether usage of 'ssh' would be feasible based on whether ControlPersist is supported.
ansible_ssh_private_key_file
Private key file used by ssh. Useful if using multiple keys and you don't want to use SSH agent.
ansible_syslog_facility
The syslog facility to log to.
ansible_python_interpreter
The target host python path. This is userful for systems with more
than one Python or not located at "/usr/bin/python" such as \*BSD, or where /usr/bin/python
is not a 2.X series Python.
ansible\_\*\_interpreter
Works for anything such as ruby or perl and works just like ansible_python_interpreter.
This replaces shebang of modules which will run on that host.
