.. _tutorial-states-part-2: ========================================================= States tutorial, part 2 - More Complex States, Requisites ========================================================= .. note:: This tutorial builds on topics covered in :ref:`part 1 <states-tutorial>`. It is recommended that you begin there. In the :ref:`last part <states-tutorial>` of the Salt States tutorial we covered the basics of installing a package. We will now modify our ``webserver.sls`` file to have requirements, and use even more Salt States. Call multiple States ==================== You can specify multiple :ref:`state-declaration` under an :ref:`id-declaration`. For example, a quick modification to our ``webserver.sls`` to also start Apache if it is not running: .. code-block:: yaml :linenos: :emphasize-lines: 4,5 apache: pkg.installed:  service.running: - require: - pkg: apache Try stopping Apache before running :py:func:`state.apply <salt.modules.state.apply_>` once again and observe the output. .. note:: For those running RedhatOS derivatives (Centos, AWS), you will want to specify the service name to be httpd. More on state service here, :mod:`service state <salt.states.service>`. With the example above, just add "- name: httpd" above the require line and with the same spacing. Require other states ==================== We now have a working installation of Apache so let's add an HTML file to customize our website. It isn't exactly useful to have a website without a webserver so we don't want Salt to install our HTML file until Apache is installed and running. Include the following at the bottom of your ``webserver/init.sls`` file: .. code-block:: yaml :linenos: :emphasize-lines: 7,11 apache: pkg.installed:  service.running: - require: - pkg: apache /var/www/index.html: # ID declaration file: # state declaration - managed # function - source: salt://webserver/index.html # function arg - require: # requisite declaration - pkg: apache # requisite reference **line 7** is the :ref:`id-declaration`. In this example it is the location we want to install our custom HTML file. (**Note:** the default location that Apache serves may differ from the above on your OS or distro. ``/srv/www`` could also be a likely place to look.) **Line 8** the :ref:`state-declaration`. This example uses the Salt :mod:`file state <salt.states.file>`. **Line 9** is the :ref:`function-declaration`. The :func:`managed function <salt.states.file.managed>` will download a file from the master and install it in the location specified. **Line 10** is a :ref:`function-arg-declaration` which, in this example, passes the ``source`` argument to the :func:`managed function <salt.states.file.managed>`. **Line 11** is a :ref:`requisite-declaration`. **Line 12** is a :ref:`requisite-reference` which refers to a state and an ID. In this example, it is referring to the ``ID declaration`` from our example in :ref:`part 1 <states-tutorial>`. This declaration tells Salt not to install the HTML file until Apache is installed. Next, create the ``index.html`` file and save it in the ``webserver`` directory: .. code-block:: html <!DOCTYPE html> <html> <head><title>Salt rocks</title></head> <body> <h1>This file brought to you by Salt</h1> </body> </html> Last, call :func:`state.apply <salt.modules.state.apply_>` again and the minion will fetch and execute the :ref:`highstate <running-highstate>` as well as our HTML file from the master using Salt's File Server: .. code-block:: bash salt '*' state.apply Verify that Apache is now serving your custom HTML. .. admonition:: ``require`` vs. ``watch`` There are two :ref:`requisite-declaration`, “require”, and “watch”. Not every state supports “watch”. The :mod:`service state <salt.states.service>` does support “watch” and will restart a service based on the watch condition. For example, if you use Salt to install an Apache virtual host configuration file and want to restart Apache whenever that file is changed you could modify our Apache example from earlier as follows: .. code-block:: yaml :emphasize-lines: 1,2,3,10,11 /etc/httpd/extra/httpd-vhosts.conf: file.managed: - source: salt://webserver/httpd-vhosts.conf apache: pkg.installed:  service.running: - watch: - file: /etc/httpd/extra/httpd-vhosts.conf - require: - pkg: apache If the pkg and service names differ on your OS or distro of choice you can specify each one separately using a :ref:`name-declaration` which explained in :ref:`Part 3 <tutorial-states-part-3>`. Next steps ========== In :ref:`part 3 <tutorial-states-part-3>` we will discuss how to use includes, extends, and templating to make a more complete State Tree configuration.