salt/doc/ref/states/highstate.rst
2013-06-07 12:47:47 -06:00

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====================================
Highstate data structure definitions
====================================
The Salt State Tree
===================
.. glossary::
Top file
The main state file that instructs minions what environment and modules
to use during state execution.
Configurable via :conf_master:`state_top`.
.. seealso:: :doc:`A detailed description of the top file </ref/states/top>`
.. glossary::
State tree
A collection of ``SLS`` files that live under the directory specified
in :conf_master:`file_roots`. A state tree can be organized into
``SLS modules``.
Include declaration
-------------------
.. glossary::
Include declaration
Defines a list of :term:`module reference` strings to include in this
:term:`SLS`.
Occurs only in the top level of the highstate structure.
Example:
.. code-block:: yaml
include:
- edit.vim
- http.server
Module reference
----------------
.. glossary::
Module reference
The name of a SLS module defined by a separate SLS file and residing on
the Salt Master. A module named ``edit.vim`` is a reference to the SLS
file ``salt://edit/vim.sls``.
ID declaration
--------------
.. glossary::
ID declaration
Defines an individual highstate component. Always references a value of
a dictionary containing keys referencing :term:`state declarations
<state declaration>` and :term:`requisite declarations <requisite
declaration>`. Can be overridden by a :term:`name declaration` or a
:term:`names declaration`.
Occurs on the top level or under the :term:`extend declaration`.
Must be unique across entire state tree. If the same ID declaration is
used twice, only the first one matched will be used. All subsequent
ID declarations with the same name will be ignored.
.. note:: Naming gotchas
Until 0.9.6, IDs could **not** contain a dot, otherwise highstate summary output was
unpredictable. (It was fixed in versions 0.9.7 and above)
Extend declaration
------------------
.. glossary::
Extend declaration
Extends a :term:`name declaration` from an included ``SLS module``. The
keys of the extend declaration always define existing :term:`ID
declarations <ID declaration>` which have been defined in included
``SLS modules``.
Occurs only in the top level and defines a dictionary.
Extend declarations are useful for adding-to or overriding parts of a
:term:`state declaration` that is defined in another ``SLS`` file. In the
following contrived example, the shown ``mywebsite.sls`` file is ``include``
-ing and ``extend`` -ing the ``apache.sls`` module in order to add a ``watch``
declaration that will restart Apache whenever the Apache configuration file,
``mywebsite`` changes.
.. code-block:: yaml
include:
- apache
extend:
apache:
service:
- watch:
- file: mywebsite
mywebsite:
file:
- managed
.. seealso:: watch_in and require_in
Sometimes it is more convenient to use the :term:`watch_in` or
:term:`require_in` syntax instead of extending another ``SLS``
file.
:doc:`State Requisites </ref/states/requisites>`
State declaration
-----------------
.. glossary::
State declaration
A list which contains one string defining the :term:`function
declaration` and any number of :term:`function arg declaration`
dictionaries.
Can, optionally, contain a number of additional components like the
name override components — :term:`name <name declaration>` and
:term:`names <names declaration>`. Can also contain :term:`requisite
declarations <requisite declaration>`.
Occurs under an :term:`ID declaration`.
Requisite declaration
---------------------
.. glossary::
Requisite declaration
A list containing :term:`requisite references <requisite reference>`.
Used to build the action dependency tree. While Salt states are made to
execute in a deterministic order, this order is managed by requiring
and watching other Salt states.
Occurs as a list component under a :term:`state declaration` or as a
key under an :term:`ID declaration`.
Requisite reference
-------------------
.. glossary::
Requisite reference
A single key dictionary. The key is the name of the referenced
:term:`state declaration` and the value is the ID of the referenced
:term:`ID declaration`.
Occurs as a single index in a :term:`requisite declaration` list.
Function declaration
--------------------
.. glossary::
Function declaration
The name of the function to call within the state. A state declaration
can contain only a single function declaration.
For example, the following state declaration calls the :mod:`installed
<salt.states.pkg.installed>` function in the ``pkg`` state module:
.. code-block:: yaml
httpd:
pkg.installed
The function can be declared inline with the state as a shortcut, but
the actual data structure is better referenced in this form:
.. code-block:: yaml
httpd:
pkg:
- installed
Where the function is a string in the body of the state declaration.
Technically when the function is declared in dot notation the compiler
converts it to be a string in the state declaration list. Note that the
use of the first example more than once in an ID declaration is invalid
yaml.
INVALID:
.. code-block:: yaml
httpd:
pkg.installed
service.running
When passing a function without arguments and another state declaration
within a single ID declaration, then the long or "standard" format
needs to be used since otherwise it does not represent a valid data
structure.
VALID:
.. code-block:: yaml
httpd:
pkg:
- installed
service:
- running
Occurs as the only index in the :term:`state declaration` list.
Function arg declaration
------------------------
.. glossary::
Function arg declaration
A single key dictionary referencing a Python type which is to be passed
to the named :term:`function declaration` as a parameter. The type must
be the data type expected by the function.
Occurs under a :term:`function declaration`.
For example in the following state declaration ``user``, ``group``, and
``mode`` are passed as arguments to the :mod:`managed
<salt.states.file.managed>` function in the ``file`` state module:
.. code-block:: yaml
/etc/http/conf/http.conf:
file.managed:
- user: root
- group: root
- mode: 644
Name declaration
----------------
.. glossary::
Name declaration
Overrides the ``name`` argument of a :term:`state declaration`. If
``name`` is not specified the :term:`ID declaration` satisfies the
``name`` argument.
The name is always a single key dictionary referencing a string.
Overriding ``name`` is useful for a variety of scenarios.
For example, avoiding clashing ID declarations. The following two state
declarations cannot both have ``/etc/motd`` as the ID declaration:
.. code-block:: yaml
motd_perms:
file.managed:
- name: /etc/motd
- mode: 644
motd_quote:
file.append:
- name: /etc/motd
- text: "Of all smells, bread; of all tastes, salt."
Another common reason to override ``name`` is if the ID declaration is long and
needs to be referenced in multiple places. In the example below it is much
easier to specify ``mywebsite`` than to specify
``/etc/apache2/sites-available/mywebsite.com`` multiple times:
.. code-block:: yaml
mywebsite:
file.managed:
- name: /etc/apache2/sites-available/mywebsite.com
- source: salt://mywebsite.com
a2ensite mywebsite.com:
cmd.wait:
- unless: test -L /etc/apache2/sites-enabled/mywebsite.com
- watch:
- file: mywebsite
apache2:
service:
- running
- watch:
- file: mywebsite
Names declaration
-----------------
.. glossary::
Names declaration
Expands the contents of the containing :term:`state declaration` into
multiple state declarations, each with its own name.
For example, given the following state declaration:
.. code-block:: yaml
python-pkgs:
pkg.installed:
- names:
- python-django
- python-crypto
- python-yaml
Once converted into the lowstate data structure the above state
declaration will be expanded into the following three state declarations:
.. code-block:: yaml
python-django:
pkg.installed
python-crypto:
pkg.installed
python-yaml:
pkg.installed
Large example
=============
Here is the layout in yaml using the names of the highdata structure
components.
.. code-block:: yaml
<Include Declaration>:
- <Module Reference>
- <Module Reference>
<Extend Declaration>:
<ID Declaration>:
[<overrides>]
# standard declaration
<ID Declaration>:
<State Declaration>:
- <Function>
- <Function Arg>
- <Function Arg>
- <Function Arg>
- <Name>: <name>
- <Requisite Declaration>:
- <Requisite Reference>
- <Requisite Reference>
# inline function and names
<ID Declaration>:
<State Declaration>.<Function>:
- <Function Arg>
- <Function Arg>
- <Function Arg>
- <Names>:
- <name>
- <name>
- <name>
- <Requisite Declaration>:
- <Requisite Reference>
- <Requisite Reference>
# multiple states for single id
<ID Declaration>:
<State Declaration>:
- <Function>
- <Function Arg>
- <Name>: <name>
- <Requisite Declaration>:
- <Requisite Reference>
<State Declaration>:
- <Function>
- <Function Arg>
- <Names>:
- <name>
- <name>
- <Requisite Declaration>:
- <Requisite Reference>