ansible-modules — stock modules shipped with ansible
Ansible ships with a number of modules that can be executed directly on remote hosts or through +
ansible-modules — stock modules shipped with ansible
Ansible ships with a number of modules that can be executed directly on remote hosts or through ansible playbooks.
Most modules other than command are idempotent, meaning they will seek to avoid changes unless a change needs to be made. When using ansible playbooks, these modules can trigger change events, as described in ansible-playbooks(5).
Unless otherwise noted, all modules support change hooks.
The command module takes the command name followed by a list of arguments, space delimited. diff --git a/html/man/ansible-playbook.5.html b/html/man/ansible-playbook.5.html index 08433495646..e495756d929 100644 --- a/html/man/ansible-playbook.5.html +++ b/html/man/ansible-playbook.5.html @@ -1,6 +1,6 @@ -
ansible-playbook — format and function of an ansible playbook file
Ansible ships with ansible-playbook, a tool for running playbooks. +
ansible-playbook — format and function of an ansible playbook file
Ansible ships with ansible-playbook, a tool for running playbooks. Playbooks can represent frequent tasks, desired system configurations, or deployment processes.
See:
ansible — run a command somewhere else
Ansible is an extra-simple tool/framework/API for doing 'remote things' over +
ansible — run a command somewhere else
Nearly all modules take key=value parameters. Some modules take no parameters, and the command +module just takes arguments for the command you want to run.
+All modules return JSON format data, thoug if you are using the command line or playbooks, you +don’t really need to know much about that.
Most modules other than command are idempotent, meaning they will seek to avoid changes unless a change needs to be made. When using ansible playbooks, these modules can trigger change events. Unless otherwise noted, all modules support change hooks.
-Stock modules:
The command module takes the command name followed by a list of arguments, space delimited. @@ -76,15 +78,16 @@ This is the only module that does not use key=value style parameters.
Example usage:
/sbin/shutdown -t now
The given shell command will be executed on all selected nodes.
This module does not support change hooks and returns the return code from the program as well as timing information about how long the command was running for.
The copy module moves a file on the local box to remote locations.
src:
-Local absolute path to a file to copy to the remote server
+Local path to a file to copy to the remote server. This can be an absolute or relative path.
dest:
-Remote absolute path where the file should end up
+Remote absolute path where the file should end up.
This module also returns md5sum information about the resultant file.
Requires that ‘facter’ and ‘ruby-json’ be installed on the remote end.
This module is informative only - it takes no parameters & does not support change hooks, -nor does it make any changes on the system.
+nor does it make any changes on the system. Playbooks do not actually use +this module, they use the ‘setup’ module behind the scenes.Deploys software from git checkouts.
+Deploys software (or files) from git checkouts.
repo:
git or http protocol address of the repo to checkout
dest:
@@ -112,13 +116,14 @@ data is a bit more verbose and nested than facter.Requires that ‘ohai’ be installed on the remote end.
This module is information only - it takes no parameters & does not support change hooks, nor does it make any changes on the system.
+Playbooks should not call the ohai module, playbooks call the ‘setup’ +module behind the scenes instead.
A trivial test module, this module always returns the integer ‘1’ on successful contact.
-This module does not support change hooks.
-This module is informative only - it takes no parameters & does not +
This module does not support change hooks and is informative only - it takes no parameters & does not support change hooks, nor does it make any changes on the system.
Writes a JSON file containing key/value data, for use in templating. Call this once before using the template modules. Playbooks will -execute this module automatically as the first step in each play.
+execute this module automatically as the first step in each play using +the variables section, so it is unneccessary to make explicit calls to +setup within a playbook.If facter or ohai are installed, variables from these programs will also be snapshotted into the JSON file for usage in templating. These variables -are prefixed with ‘facter‘ and ‘ohai” so it’s easy to tell their source.
-metadata
-Optionally overrides the default JSON file location of /etc/ansible/setup or ~/ansible/setup -depending on what remote user has been specified.
-If used, also supply the metadata parameter to the template module.
+are prefixed with ‘facter‘ and ‘ohai” so it’s easy to tell their source. +All variables are then bubbled up to the caller.anything
any other parameters can be named basically anything, and set a key=value pair in the JSON file for use in templating.
@@ -151,32 +155,39 @@ pair in the JSON file for use in templating.Templates a file out to a remote server. Call the setup module prior to usage.
src
-path of a Jinja2 formatted template on the local server
+path of a Jinja2 formatted template on the local server. This can be a relative +or absolute path.
dest
location to render the template on the remote server
-metadata
-location of a JSON file to use to supply template data. Default is /etc/ansible/setup -which is the same as the default for the setup module. Change if running as a non-root -remote user who does not have permissions on /etc/ansible.
This module also returns md5sum information about the resultant file.
This module is in plan.
-This module is in plan.
-To write your own modules, simply follow the convention of those already available in /usr/share/ansible. Modules must return JSON but can be written in any language. -Modules should return hashes, but hashes can be nested. -To support change hooks, modules should return hashes with a changed: True/False -element at the top level. Modules can also choose to indicate a failure scenario -by returning a top level ‘failure’ element with a True value, and a ‘msg’ element -describing the nature of the failure. Other values are up to the module.
+Modules should return hashes, but hashes can be nested. +To support change hooks, modules should return hashes with a changed: True/False +element at the top level:
+{
+ 'changed' : True,
+ 'something' : 42
+}
+Modules can also choose to indicate a failure scenario by returning a top level ‘failure’ +element with a True value, and a ‘msg’ element describing the nature of the failure. +Other return values are up to the module.
++++
+- {
+- ‘failure’ : True, +‘msg’ : “here is what happened...”
+}
+
When shipping modules, drop them in /usr/share/ansible, or specify the module path to the +command line tool or API. It is easy to test modules by running them directly on +the command line, passing them arguments just like they would be passed with ansible.
The Inventory File, Patterns, and Groups
+Playbooks are a completely different way to use ansible and are particularly awesome. They are the basis for a really simple configuration management and deployment system, unlike any that already exist, and one that is very well suited to deploying complex multi-machine applications. While you might run the main ansible program for ad-hoc tasks, playbooks are more likely to be kept in source control and used to push out your configuration or assure the configurations of your remote systems are in spec.
+Playbooks are a completely different way to use ansible and are particularly awesome.
+They are the basis for a really simple configuration management and multi-machine deployment system, unlike any that already exist, and one that is very well suited to deploying complex applications.
+While you might run the main /usr/bin/ansible program for ad-hoc tasks, playbooks are more likely to be kept in source control and used to push out your configuration or assure the configurations of your remote systems are in spec.
Playbooks are expressed in YAML format and have a minimum of syntax. Each playbook is composed @@ -89,30 +91,39 @@ back on the webservers group, etc:
The hosts line is alist of one or more groups or host patterns, seperated by colons, as -described in the ‘patterns’ documentation.
+The hosts line is a list of one or more groups or host patterns, seperated by colons, as +described in the ‘patterns’ documentation. This is just like the first parameter to /usr/bin/ansible.
A list of variables that can be used in the templates, action lines, or included files. -Variables are deferenced using jinja2 syntax like this:
-{{ varname }}
-These variables will be pushed down to the managed systems for use in templating operations, where -the way to dereference them in templates is exactly the same.
+A list of variables and values that can be used in the plays. These can be used in templates +or ‘action’ lines and are dereferenced using `jinja2` syntax like this:
++{{ varname }}
Further, if there are discovered variables about the system (say, if facter or ohai were installed) these variables bubble up back into the playbook, and can be used on each system just like explicitly set variables. Facter variables are prefixed with ‘facter_‘ -and Ohai variables are prefixed with ‘ohai_‘.
+and Ohai variables are prefixed with ‘ohai_‘. So for instance, if I wanted to write the +hostname into the /etc/motd file, I could say: ++++
+- name: write the motd
+- action: template src=/srv/templates/motd.j2 dest=/etc/motd
+
And in /srv/templates/motd.j2::
+You are logged into {{ facter_hostname }}
+But we’re getting ahead of ourselves. Let’s talk about tasks.
Each play contains a list of tasks. Tasks are executed in order, one at a time, against -all machines matched by the play’s host pattern, before moving on to the next task. -Hosts with failed tasks are taken out of the rotation for the entire playbook. If things fail, -correct the problem and rerun. Modules other than command are idempotent, meaning if you -run them again, they will make the changes they are told to make to bring the system to -the desired state.
+all machines matched by the play’s host pattern, before moving on to the next task. +Hosts with failed tasks are taken out of the rotation for the entire playbook. If things fail, +simply correct the playbook file and rerun.
+Modules other than command are idempotent, meaning if you run them again, they will make the +changes they are told to make to bring the system to the desired state.
The action line is the name of an ansible module followed by parameters. Usually these are expressed in key=value form, except for the command module, which looks just like a Linux/Unix command line. See the module documentation for more info.
+Variables, as mentioned above, can be used in action lines. So if, hypothetically, you wanted +to make a directory on each system named after the hostname ... yeah, that’s I know silly ... you could +do it like so:
+++
+- name: make a directory
+- action: mkdir /tmp/{{ facter_hostname }}
+
Nearly all modules are written to be ‘idempotent’ and can signal when they have affected a change on the remote system. If a notify statement is used, the named handler will be run against -each system where a change was effected, but NOT on systems where no change occurred.
+each system where a change was effected, but NOT on systems where no change occurred. This happens +after all of the tasks are run. For example, if notifying Apache and potentially replacing lots of +configuration files, you could have Apache restart just once, at the end of a run. If you need +Apache restarted in the middle of a run, you could just make a task for it, no harm done. Notifiers +are optional.Handlers are lists of tasks, not really any different from regular tasks, that are referenced -by name.
+by name. Handlers are what notifiers notify. If nothing notifies a handler, it will not run. +Regardless of how many things notify a handler, it will run only once, after all of the tasks +complete in a particular play.Not all tasks have to be listed directly in the main file. An include file can contain a list of tasks (in YAML) as well, optionally passing extra variables into the file. -Variables passed in can be deferenced like this:
+Variables passed in can be deferenced like this (assume a variable named ‘user’) +++{{ user }}
For instance, if deploying multiple wordpress instances, I could contain all of my tasks +in a wordpress.yml file, and use it like so:
-+{{ variable }}
In addition to the explicitly passed in parameters, all variables from the vars section +are also available.