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- So let's have a look at
how we can use variables

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in the a playbook.

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Variables themselves can be
defined in different ways.

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You can set them in the playbook directly,

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but that is bad practice as
the site-specific information,

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in that case, is not
separated from the code.

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But hey, let's face it,

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in some situations, you can do it anyway.

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If you start your playbook
with a list of variables

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at least you make it easy to modify

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if you're going to run it in
some specific information.

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If you are referring to a variable

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inside the YAML code in your playbook

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the default rule is that
you need double braces.

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As in the variable is
double braces, my variable.

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And the double braces make
that the value of the variable

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is interpreted the right way.

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If a value starts with a variable,

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the variable needs to be
between double quotes,

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as well as double braces.

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Notice that in the line that
you can see here on the slide

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the entire value is between double quotes

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not just the variable,

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but the fact that the value
starts with the variable

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makes it a variable must
be between double quotes.

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If you are using a variable
in a when statement

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which we will talk
about in the next lesson

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curly braces are omitted,

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and there's a couple of other situations

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where variables are
noted in a different way.

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Can be a little bit confusing,

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but hey let's try to
figure out how it works.

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Before doing anything else,

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let's have a look at the basic
example of using variables.

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So this time we are looking
at the basics directory.

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In the basics directory there
is variables_example.yaml,

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and let's have look at this
variables_example.yaml.

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As you can see it's pretty
easy to understand playbook.

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It creates a user using a variable.

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On the host rocky,

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the vars are defined
in the playbook itself.

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So we have a variable and in the variable

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I'm setting the variable
user to the value lisa.

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So the variable, also
known as the key, is user.

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And lisa is the value
that I want to set it to.

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Notice that the variables
integrate in the play header.

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That is the highest level in the playbook

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where you can set your variables.

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It also means that if you
have a multiple play playbook

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you need a different approach

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to set your variables accordingly.

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Next, we have the tasks and
in the tasks we have name,

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create a user double curly braces user

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on host ansible_hostname.

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User is a variable that
we defined right here.

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So in the task description,
we will see that it'll create

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the user and then it'll create this user

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on the host ansible_hostname.

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Now this ansible_hostname
is also noted as a variable.

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What kind of variable is this?

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This is an Ansible fact.

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Facts are discovered variables
and will talk about facts

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in more detail later.

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Next we have the user
module and the user module

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is name and name is referring
to the value of the variable.

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But as this time, the value
is starting with the variable

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or the entire value is just the variable.

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The entire value must be
between double quotes.

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So mind your syntax.

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Let's run it.

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So you can see it's starting
with the fact gathering.

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It's a mandatory component,

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needs to discover what's
going on on the notes.

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So there we can see fact
gathering was successful

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and it created user lisa on host ansible.

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So here we have lisa which
is the value of the variable

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and host ansible1 is the
value of the variable as well,

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the variable ansible host name.

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Now this is kind of a primitive structure.

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It's just printing ansible1
that's the first host name

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that it will encounter.

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And then you can see it works on ansible2

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as well as ansible1.

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Don't worry about it.

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We'll talk about when statements later

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and loops that allow you
to print all host names,

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if you want to.

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I don't think it's really necessary now.

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What is necessary is that we see

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the variable is substituted.

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Now there's another way
of running a playbook

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with variables.

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That is ansible-playbook
variables_example -e user is bob.

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What are we doing here?

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We are overwriting the
variable on the commands line.

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That goes for any option
that you use in Ansible.

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If you define the option
on the command line,

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it has higher precedence
and it'll always win.

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So in this case, user
will be bob and not lisa.

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That's a golden rule in Ansible.

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The most specific setting will always win.

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As you can see, create
user bob on host ansible1.

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So user bob is what is created.

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Did not exist yet, so we see
it changed and it changed.

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So this is what you need to
know about basic variable usage.