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Hey everyone and welcome back to another skill in the LPIC 2 certification course.

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Okay so what we're going to be focusing on in this skill right here is all about being

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able to set up a web server.

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Now there are different types of web servers available that you can use on Linux.

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The main focus for us right now is going to be an Apache web server.

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Now all Apache is, it is an open source utility.

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Now if you don't know what open source is, it just means that the source code for the

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project is widely available.

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You can actually read this source code and it's not just open to read, it's also free

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to use under the Apache license.

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So naturally this makes a very good web server to use because it's not going to cost you

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anything, you can easily see the code to see how it actually operates.

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This really is a great solution for us, especially for demo purposes and because we do want to

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be knowing this once again for the LPIC 2 certification.

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So really what is an Apache web server used for?

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We'll think about it.

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What it's going to do is going to allow us to serve up web pages so no real big revelation

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right there.

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Now what this actually means is that we can serve up these services to our internal users,

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perhaps you want to present some type of web page to them to be able to manage their own

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system or if we so choose we can present this web page as a front facing external website

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that could be reached over the internet.

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The reality is how the Apache web server is implemented is completely flexible and up

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to you.

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Now the way Apache works is by leveraging something called HTML.

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Now if you happen to have much familiarity with web development you will actually understand

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or be at least familiar with the concept of HTML.

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But if you're not familiar all HTML is, it stands for the Hypertext Markup Language.

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And all this is going to be doing is going to provide us a type of structure that we

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can use so that we can display the pages that we want on to our website.

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It is the language that our web browsers can read.

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So if on your website you want to have maybe some bullet points like point one, point two,

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so on and so forth.

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Or if you want to embed some type of images maybe say some JPEG images or you want to

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format your actual text into paragraphs whatever it may be.

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Perhaps you want to add in different headings.

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Maybe you want to use headings of different sizes for more important issues and smaller

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headings for less important issues.

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The reality is all of this can be done using HTML which like I say is what Apache is going

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to leverage.

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Now with respect to Apache actually using HTML so that we can ultimately render our

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web pages all of this hinges upon particular configuration files.

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And like so much of what we learn within the LPIC certification courses, the actual location

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of these configuration files are of primary importance.

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So we do actually want to be knowing whereabouts these configuration files that Apache is going

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to leverage.

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We need to know where exactly they are and unsurprisingly there actually is once again

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a difference depending on if you are using a Red Hat based system or a Debian based system.

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Now with respect to Debian based systems the actual package itself is simply known

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as Apache 2 and this package on Debian is going to be located within the Etsy directory

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and then within a folder simply titled Apache 2.

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So really easy to remember the name of the package is basically within the Etsy directory

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itself.

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Now things are a little bit different with respect to Red Hat based systems like I say

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the actual package itself is not going to be called Apache 2, the package is going to

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be called HTTPD.

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Now the reason for this is because in order to access web pages we are going to be actually

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accessing that data using the HTTP protocol.

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This is the Hypertext Transfer Protocol.

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This is what you see when you use your web browser.

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So this might be a little bit confusing.

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This is the transport we use to get the information and the information we are consuming is leveraging

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HTML.

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That is the difference but basically here this is just the Hypertext Transfer Protocol

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deamin effectively.

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Now on a Red Hat based system this HTTPD package is going to be once again located within the

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Etsy directory but this time in a folder called HTTPD.

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So that really is the difference.

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The package name is going to be in the Etsy directory just like we saw with the Debian

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based Apache server package.

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So these packages are going to reside within these respective folders and within these

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particular folders we are going to have like I say these configuration files.

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Now these configuration files are not just going to be one large monolithic file that

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contains absolutely everything like so much of what we see within Linux.

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These are actually going to be modular such that effectively the configuration files are

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broken up into small chunks.

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This once again like we see before makes things a lot more manageable so as opposed to dealing

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with a huge configuration file that controls absolutely everything.

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We will be dealing with more specific and smaller files that control very particular

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aspects of the configuration.

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Like I say a common theme on Linux because this architecture happens to work really

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quite well.

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Now with respect to our Debian based systems there is quite a unique directory structure

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that we have to talk about.

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The first thing that I really should mention is that the main configuration file is going

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to be one called Apache2.conf.

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Now within this configuration file we are actually going to point to additional folders

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and these folders are going to be one called sites-enabled and the other one is going to

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be mods-enabled.

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Now these actual folders are what are called simlinks.

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Now we actually talked about simlinks in the Lpik1 certification course so no doubt you

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are familiar with this concept.

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So all these folders do in effect then is point to additional folders.

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So let me show you what the relationships actually look like.

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Let's take for example this simlink first.

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So sites-enabled.

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This simlink folder is actually going to point to a folder called sites-available.

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That is the relationship right there and with respect to our mods-enabled the mods-enabled

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simlink folder this one is going to point to a directory known as mods-available.

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And within these actual folders that we see here we are going to have a whole bunch of

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configuration files that have to be loaded by the system in order to operate correctly.

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But you might be asking why even bother having these simlinks right here.

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Instead why doesn't the Apache 2.con file just not point to this directory directly.

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Well the reality is by invoking our simlinks it just simply makes things more manageable.

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So let me tell you why this is because think about it if we have our simlink sites enabled

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which really just points to this main directory of sites-available.

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If we want to temporarily disable any of the configurations that are within this directory

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right here we don't actually have to go in and delete anything here because if we happen

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to go into this directory and delete those files then we could lose them forever.

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Instead if we just want to disable that behavior all we could do is simply and temporarily

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remove this simlink and by doing this we actually haven't changed anything physically within

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this directory but we've broken the link to this directory so it's not actually going

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to be active.

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And once again if we want the configurations within this directory to once again become

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active once more well we just recreate this simlink once again to point to this file or

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this directory should I say and then all the configurations within this folder structure

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are going to be active once again the same is true of the mods enabled simlink which

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points to the mods available directory structure.

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So really this is all about making things much much easier as well as by the way much

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safer to manage because like I say you're not having to go in and physically remove

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configuration files from the actual disk itself.

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Now like I say we do have differences between Red Hat and Debian with respect to Red Hat

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we no longer have this Apache 2.conf file no surprises since the actual package is not

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called Apache 2.

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Instead you can probably guess what the configuration file is going to be called instead the main

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configuration file here is going to be HTTP.conf so a little bit different once again.

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Also with respect to Red Hat we're not actually invoking this simlink behavior instead this

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configuration file HTTP.conf this just points to a directory structure known as the conf.d

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directory and within this directory structure we have the configuration files that the web

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server needs to actually operate and we just interact with them directly as opposed to

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the way we do it on the Debian based system.

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Okay so now that we have a rough idea of how Apache actually operates within these systems

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how about we actually take a quick peek at what these configuration files do now in order

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to do so the first thing I'm going to have to do is to install the Apache web server

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package now I happen to be on a Debian based system so I'm going to install the Apache

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2 package not the HTTP package so what I will do here is I will say sudo apt update and

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I'll type in my password okay Apache 2 and I will do dash y to answer yes to the prompt

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and the installation will begin okay so now that I have actually installed this I should

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now have this directory right here so if I go into etsy and go into Apache 2 this now

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exists now what we're going to see here is what exactly I talked about remember these

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particular files say for example or rather these particular directories should I say

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the sites available the sites enabled the mods available and the mods enabled now the enabled

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ones are going to be our sim links so if I do an LS dash L on mods enabled and list everything

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in here we can see here that indeed we actually have all these sim links that point to particular

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configurations and these actually live within the mods available directory see that there

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but in mods enabled but the point to mods available and once again we can tell these are sim

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links with these little arrows the highlighting and more concretely we have the little L at the

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very left hand side right here and similarly if I just clear the screen and I do an LS dash L on

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sites enabled once again we're going to see sim links and here in this case we only have a

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singular sim link but as you'll notice it points through the sites available directory so we could

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go into these directories such as the sites available and if I do an LS right here we can see

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these are the actual configuration files that are ultimately controlling the behavior here but we

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can like I say access them within the sim link so I can go into the sites enabled directory do an

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LS we can see we have this configuration file right here if I do a sudo nano on this configuration

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file we can see a whole bunch of information so right here we can actually see that this

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particular service is going to be running on star which means on any IP address i.e. any IP

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addresses we have configured on our server this service is going to listen on any of those IP

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addresses on port 80 now port 80 is a well-known port for web access so this should come as no

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surprise but we also have some additional information here which is really quite important this one

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right here is indeed very important the document routes this is really going to be the main

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directory that is going to hold all of your files with respect to your service so within here the

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var directory www and then the html but actually going to find html files that are going to be

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ultimately rendered by the Apache service for our web pages now the other file I want to show you is

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that main configuration file we talked about remember on Debian based system this is going to

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be called Apache 2.conf so if I go back a directory right here so I'm in the Apache 2 directory I do

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an LS here is this main configuration file right here so if I open this one up as we can see here

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this is the main server configuration file for the Apache server itself if we scroll on down we

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can actually see such things as the include optional keyword which is actually specified we're

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going to load the configuration files within the sites enable directory and we can see here we

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actually have a wildcard value which is the star meaning that any file within this directory that

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ends with .conf is going to be read as a configuration file so if we go back we're going to sites

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enabled we do an LS-L any configuration files that we can see here the end in .conf which is this

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sim link here this is going to be read in and again it just points to the sites available

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directory where we have the physical location for this configuration file and like I say that Apache

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2.conf configuration file has way way way more information than we can actually cover within

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this nugget now what we actually saw within this configuration file like I say we can see this

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document root so how about we go and have a look at this particular directory then so we'll go back

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out and I'll go into my var directory go into www and then HTML if I clear the screen to a PWD and

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LS we can see this index dot HTML configuration file right here now if I happen to open this we're

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going to see a whole bunch of HTML and you don't have to worry about all of this particular

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formatting here this is HTML code you do not have to be able to be a web developer who is very strong

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on this just understand what you happen to be looking at here this is just effectively instructions

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for how our web page is going to be rendered so what we actually have here is this index dot

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HTML file like I say and this is actually going to be a default file that the Apache web server

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is going to look for and read so if everything that is in this configuration file is going to be

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read by Apache and ultimately rendered that means what we actually see in this file we could

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actually view it via a web browser now one thing I will do right now is I will check my IP address

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I'll say IP adder we can see my local address is 192 1680 44 if I browse to this address in a web

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browser we should actually see the contents of this index dot HTML page right here so let's try that

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then so I'll go to my virtual machine browser right here I'll type in the IP address 192 1680

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44 if I hit enter the browser is actually showing the Apache to default page this is ultimately

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what we see within the contents of that index dot HTML file so what I can do here is if I go in and

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I just maybe say remove this okay so it no longer exists in fact I need to do a pseudo RM so now it

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no longer exists what I'll do is I'll recreate it okay so I'll say HTML now what I'm going to do here

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is some very basic HTML now you don't have to be worrying about being able to write this HTML

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code I just want to show you a basic example here so I'm going to use these particular

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tags h1 and then a closing tag of h1 this h1 is just simply to create a heading so I can just say

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this is a big heading welcome to the page and then I can create a smaller heading using an h2

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label or an h2 tag so you've found IPv0s web server and I'll do a closing tag for h2 and I can make

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an even smaller heading using an h3 heading hope you have a great time and I'll create another h2

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heading which will be of medium size so a little bit bigger once again come back again soon okay so

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if I happen to save this file right here we now have this index dot HTML recreated if I go to my

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web page and I reload this check this out we can see here the main heading for the web page we have

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a medium size heading then a small heading then again another medium size heading now of course

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this is a very very basic web service there is nothing too savvy with the html code that we're

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seeing here but ultimately the point remains the same we have these particular configuration files

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that are ultimately going to be referencing particular pieces of html which we can feed

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into the Apache web server that can ultimately render this service which we can then expose to

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our internal users as a private web page or if we so choose expose it as a public web page to be

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consumed by regular users on the internet so that is us for our introduction into Apache I hope this

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has been informative for you and I'd like to thank you for viewing