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Okay friends, so now that we understand how to utilize Ginger2 to do things

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like variable substitution

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as well as to create loops and conditional statements, let's now use Ginger2 to

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actually

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make a configuration change on our devices.

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Now the actual configuration that we are going to build is going to be really

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quite simple.

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All we're going to do is we're going to change the configurations of our DNS

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server for each

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of the devices in our system.

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So here is what I'm going to do, I'm first going to go to my host variables and

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let's
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let's

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go into let's say blue box for example, okay.

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So inside of here, let me just add the key DNS servers and this is going to be

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an array

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object that's going to allow me to specify all of the servers that I want to

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use.

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So let's just say we want to use, in this case here, 8.8.8.8, as well as 8.8.4.

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4.

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So let's copy it right and quit.

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And for the yellow box, again, very important, we want to use the same key.

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So it's going to be DNS servers and then we specify the servers that we want to

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use.

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So let's just maybe say this one is going to use 8.8.8.8, as well as let's

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maybe say
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maybe say

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1.1.1.1, which I don't believe actually as a DNS server, but nevertheless, it's

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just

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for a demonstration.

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So what we want to do is we want to create a template that is going to make

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that configuration

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change.

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So go into our templates directory.

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Okay, here we are.

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And I'm going to create a new template just called, let's just say DNS dot j2.

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Okay.

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So what is the base template going to look like?

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Well, think about what file are we going to try to modify?

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In this case here, I'm going to try to modify the 8.8.8. resolve.conf
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In this case here, I'm going to try to modify the 8.8.8. resolve.conf

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configuration file.

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So let's go and look at that for reference.

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I will just say cat, 8.8. resolve.conf.

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And this is the file right here.

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Now think about it.

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What would we do if we wanted to have multiple deformed servers?

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So the way we'd actually modify this, we could say sudo vim, 8.8. resolve.conf.

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Going to insert more than again, this is not necessarily the way we'd want to

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do this.

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It's just for demonstration.

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You can manage this directly via network manager.

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And if you want to add in another server, i.e. we have multiple servers, we

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would say,

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name server once again, and then specify the corresponding server configuration
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name server once again, and then specify the corresponding server configuration

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, which

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would be in this case here, maybe a 1.1.1.1.

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So basically, imagine this as a template.

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Okay, let's copy this here.

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And we'll go to our templates right here.

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So let's paste this in.

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Now, let's just go back to this right here in our press escape colon quits and

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exclamation

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mark.

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We don't want to write those changes.

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Let's just tap this to ensure that there's nothing being changed.

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We can see we didn't actually modify anything.

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Now think about this.

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When we happen to push our rendered configuration, let's just leave this part
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When we happen to push our rendered configuration, let's just leave this part

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here at the top.

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That is the comment generated by network manager and search local domain.

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Let's just leave that.

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Okay.

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So we'll just hard code that directly into our template.

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Now this part here, we see the same thing repeating twice.

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If we see a repetition, this is a candidate for a loop.

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So we're going to invoke a loop.

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And within that loop, we want to hard code the word name server followed by a

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variable

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value, which will actually denote the IP address configuration of the name

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server and we'll

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call that directly from our host variable file.
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call that directly from our host variable file.

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So basically, we want a loop and within that loop, a variable.

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Okay.

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So let's actually try to modify this and insert mode and let's use our loop.

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Okay.

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So color brace percentage same and I'll just say for server, again, call this

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anything

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you so wish it's just a variable value in and what is the actual key here?

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Okay.

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So we can see here the key to be of use is DNS underscore servers.

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We're going to have to reference that.

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Okay.

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So DNS underscore servers and then percentage color brace that gives us our for
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So DNS underscore servers and then percentage color brace that gives us our for

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loop.

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Now let me delete this low entry.

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And like I say, the name server, we're going to leave that word hard coded, but

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the actual

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value here, this is going to vary.

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So how do we actually access the variable?

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We'll just say double color brace.

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And all we need to do here is use the variable server because that's going to

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give us each

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element within the array, ie each IP address.

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Now what are we actually missing here?

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We have started a for loop.

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Therefore, we're going to have to close it.

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So we'll say color brace percent and four percent color brace.
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So we'll say color brace percent and four percent color brace.

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So if I press escape colon wq, now we have the DNS dot J2.

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Okay.

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So let's go and check this out.

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Then let's go and I'll just copy over my playbook and let's just call this or

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render

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to dot yml.

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Okay.

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So let's go in here and modify it.

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So the source this time is not going to be test dot J2.

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That is not the template we want.

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The template we want this time is going to be DNS dot J2.

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Now that is the file that we're going to render, but where do we actually want

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to place

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that file?
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that file?

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Well, in the destination parameter, we want to specify that this should go into

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the Etsy

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resolve dot conf file.

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So if I just escape colon, write and quit, clear the screen and just say Ans

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ible hyphen

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playbook and also render to and enter and we can see the changes have been

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applied.

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So let's go to each device.

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So if I go to the yellow box and I just say vim, it's a resolve dot conf.

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Look at this right here.

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The yellow box has the configuration name server, eight dot eight dot eight dot

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eight

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and name server one dot one dot one dot one just as we saw within the variable
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and name server one dot one dot one dot one just as we saw within the variable

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files for

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that particular host.

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Now if we go to the blue box and say vim, it's a resolve dot conf.

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Look at this right here, we see name server eight dot eight dot eight dot eight

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and name

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server eight dot eight dot four dot four again, exactly mirroring the

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configurations that we

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have for the host variables for that particular device.