.. _states-tutorial: ===================================== States tutorial, part 1 - Basic Usage ===================================== The purpose of this tutorial is to demonstrate how quickly you can configure a system to be managed by Salt States. For detailed information about the state system please refer to the full :ref:`states reference `. This tutorial will walk you through using Salt to configure a minion to run the Apache HTTP server and to ensure the server is running. .. include:: /_incl/requisite_incl.rst Setting up the Salt State Tree ============================== States are stored in text files on the master and transferred to the minions on demand via the master's File Server. The collection of state files make up the ``State Tree``. To start using a central state system in Salt, the Salt File Server must first be set up. Edit the master config file (:conf_master:`file_roots`) and uncomment the following lines: .. code-block:: yaml file_roots: base: - /srv/salt .. note:: If you are deploying on FreeBSD via ports, the ``file_roots`` path defaults to ``/usr/local/etc/salt/states``. Restart the Salt master in order to pick up this change: .. code-block:: bash pkill salt-master salt-master -d Preparing the Top File ====================== On the master, in the directory uncommented in the previous step, (``/srv/salt`` by default), create a new file called :conf_master:`top.sls ` and add the following: .. code-block:: yaml base: '*': - webserver The :ref:`top file ` is separated into environments (discussed later). The default environment is ``base``. Under the ``base`` environment a collection of minion matches is defined; for now simply specify all hosts (``*``). .. _targeting-minions: .. admonition:: Targeting minions The expressions can use any of the targeting mechanisms used by Salt — minions can be matched by glob, PCRE regular expression, or by :ref:`grains `. For example: .. code-block:: yaml base: 'os:Fedora': - match: grain - webserver Create an ``sls`` file ====================== In the same directory as the :ref:`top file `, create a file named ``webserver.sls``, containing the following: .. code-block:: yaml apache: # ID declaration pkg: # state declaration - installed # function declaration The first line, called the :ref:`id-declaration`, is an arbitrary identifier. In this case it defines the name of the package to be installed. .. note:: The package name for the Apache httpd web server may differ depending on OS or distro — for example, on Fedora it is ``httpd`` but on Debian/Ubuntu it is ``apache2``. The second line, called the :ref:`state-declaration`, defines which of the Salt States we are using. In this example, we are using the :mod:`pkg state ` to ensure that a given package is installed. The third line, called the :ref:`function-declaration`, defines which function in the :mod:`pkg state ` module to call. .. admonition:: Renderers States ``sls`` files can be written in many formats. Salt requires only a simple data structure and is not concerned with how that data structure is built. Templating languages and `DSLs`_ are a dime-a-dozen and everyone has a favorite. Building the expected data structure is the job of Salt :ref:`renderers` and they are dead-simple to write. In this tutorial we will be using YAML in Jinja2 templates, which is the default format. The default can be changed by editing :conf_master:`renderer` in the master configuration file. .. _`DSLs`: http://en.wikipedia.org/wiki/Domain-specific_language .. _running-highstate: Install the package =================== Next, let's run the state we created. Open a terminal on the master and run: .. code-block:: bash salt '*' state.apply Our master is instructing all targeted minions to run :func:`state.apply `. When this function is executed without any SLS targets, a minion will download the :ref:`top file ` and attempt to match the expressions within it. When the minion does match an expression the modules listed for it will be downloaded, compiled, and executed. .. note:: This action is referred to as a "highstate", and can be run using the :py:func:`state.highstate ` function. However, to make the usage easier to understand ("highstate" is not necessarily an intuitive name), a :py:func:`state.apply ` function was added in version 2015.5.0, which when invoked without any SLS names will trigger a highstate. :py:func:`state.highstate ` still exists and can be used, but the documentation (as can be seen above) has been updated to reference :py:func:`state.apply `, so keep the following in mind as you read the documentation: - :py:func:`state.apply ` invoked without any SLS names will run :py:func:`state.highstate ` - :py:func:`state.apply ` invoked with SLS names will run :py:func:`state.sls ` Once completed, the minion will report back with a summary of all actions taken and all changes made. .. warning:: If you have created :ref:`custom grain modules `, they will not be available in the top file until after the first :ref:`highstate `. To make custom grains available on a minion's first :ref:`highstate `, it is recommended to use :ref:`this example ` to ensure that the custom grains are synced when the minion starts. .. _sls-file-namespace: .. admonition:: SLS File Namespace Note that in the :ref:`example ` above, the SLS file ``webserver.sls`` was referred to simply as ``webserver``. The namespace for SLS files when referenced in :conf_master:`top.sls ` or an :ref:`include-declaration` follows a few simple rules: 1. The ``.sls`` is discarded (i.e. ``webserver.sls`` becomes ``webserver``). 2. Subdirectories can be used for better organization. a. Each subdirectory is represented with a dot (following the Python import model) in Salt states and on the command line . ``webserver/dev.sls`` on the filesystem is referred to as ``webserver.dev`` in Salt b. Because slashes are represented as dots, SLS files can not contain dots in the name (other than the dot for the SLS suffix). The SLS file ``webserver_1.0.sls`` can not be matched, and ``webserver_1.0`` would match the directory/file ``webserver_1/0.sls`` 3. A file called ``init.sls`` in a subdirectory is referred to by the path of the directory. So, ``webserver/init.sls`` is referred to as ``webserver``. 4. If both ``webserver.sls`` and ``webserver/init.sls`` happen to exist, ``webserver/init.sls`` will be ignored and ``webserver.sls`` will be the file referred to as ``webserver``. .. admonition:: Troubleshooting Salt If the expected output isn't seen, the following tips can help to narrow down the problem. Turn up logging Salt can be quite chatty when you change the logging setting to ``debug``: .. code-block:: bash salt-minion -l debug Run the minion in the foreground By not starting the minion in daemon mode (:option:`-d `) one can view any output from the minion as it works: .. code-block:: bash salt-minion Increase the default timeout value when running :command:`salt`. For example, to change the default timeout to 60 seconds: .. code-block:: bash salt -t 60 For best results, combine all three: .. code-block:: bash salt-minion -l debug # On the minion salt '*' state.apply -t 60 # On the master Next steps ========== This tutorial focused on getting a simple Salt States configuration working. :ref:`Part 2 ` will build on this example to cover more advanced ``sls`` syntax and will explore more of the states that ship with Salt.