How to Get Your Own Web Server to Play With at Home

Transcription

1 How to Get Your Own Web Server to Play With at Home This document will tell you how to create a virtual server. A virtual server runs on a virtual machine (VM). A virtual machine is a software representation of a concrete computer, which to software running on it appears to be physical hardware. That means that you can run an entirely "different" computer inside a window on your desktop. It also means you can run different operating systems than the one hosting the virtual machine. In our case, we are going to run Linux in a virtual machine on whatever you normally use. 1. Download VirtualBox: You need to get the installer for your host operating system. The host operating system is the system that VirtualBox itself will be installed on. If you have Windows, you need the Windows hosts version, if you have a Mac, you ned the OS X host version. If you have Linux, you probably already know all this, so why are you reading it? 2. Install VirtualBox. You do this in the usual way you install software for your host. Now you have a choice. You can create a VM and install everything from scratch, of you can download a pre-built VM (also sometimes called an "appliance"). We're going to build from scratch because it is more fun and will impress your friends more. 3. Start virtual box (you run it just like any other software you should find it in your launcher menu (Start menu on Windows. I don't know what you call it on a Mac). 4. Click the "New" icon, or choose the "New..." item from the "Machine" menu 5. Give the VM a name, choose "Linux" for the Type, and for the Version pick whatever best matches your distribution. I'm going to use PCLinuxOS, which is not in the list, so we'll choose "Other Linux" I'm also not sure what kind of computer hardware you are using, but 32-bit will

2 work on both 32-bit and 64-bit hosts, so we won't go wrong choosing that. By the way, the bit'ness of the operating system refers to the size of a word that the computer consumes while processing instructions. Usually, the central processing unit (CPU) determines the word size of a system. In a 32-bit system, the processor takes instructions and operands that are 32 bits wide. On a 64-bit system, the processor takes instructions and operands that are 64 bits wide. A bit is binary digit that is, it is a digit that can have the value 1 or the value 0. That's it. A computer processes bigger values by stringing bits together. The maximum value a computer can natively process is determined by its processor word size. In a 32-bit system, the maximum value the system can process is whatever can be represented by a string of 32 bits (e.g., an unsigned integer value of 4,294,967,296). If you don't know anything about binary arithmetic, it works just like base-10 arithmetic you use very day, except you move to the next place every 2 increments instead of every 10. You can find a lot about binary math on the Internet if you really want to know. The important thing for us, is that we want the bit'ness of our operating systems and our virtual and real machines to all be compatible. Anyway, your VM definition screen should look something like this now:

3 6. Click "Next" The default memory size on this screen is usually the lowest you can get away with. Since the VM will share memory (RAM) with your host operating system, you can't give all the memory in your computer to it. Whatever you do give it must be entirely reserved for the VM the host and the VM can't be allowed to address the same blocks of memory or both of them will crash. So whatever you assign here will NOT be available to your host OS. I still don't know what kind of computer your have, so we'll keep this selection low. It probably defaults to 256 MB that's too low. Let's bump it to 512 MB and click "Next" 7. Now you need to give your virtual computer a hard drive. Virtual hard drives are really just files on your host computer. Make sure the "Create a virtual hard drive now" item is ticked and click "Create"

4 8. On the next screen we need to select the format for the files that hold the virtual hard drive. This option is included with VirtualBox so that it is compatible with other hypervisors (VirtualBox is a hypervisor software that manages and supports virtual machines). You can leave the default and click "Next" 9. The next option is a fun one. One of the neat things about VMs is that to some degree they can be changed while running. You can say that you want your hard drive to be pre-allocated or allocate it as needed. Allocating all at once creates a file of the size you specifywhen the VM is created. Allocating as-needed, initially allocates a small file and then as that fills, the file is expanded up to a maximum size that you specify. I usually have plenty of disk to spare, so I opt for faster run-time performance and choose "Fixed Size" here. We'll do that now I doubt you are running tight on disk. Then click "Next": 10. Now you need to say where you want the file that represents the virtual hard drive to live on your real hard drive. The file location defaults to where VirtualBox usually keeps stuff and the name defaults to the VM name. I'm just going to change the name, but leave it in the default

5 location. I'm also going to leave the default size of 8 GB. That's a reasonable disk size for a small-scale Linux web server. Even libsystems.clemson.edu, which hosts things like staffweb, the library blog, and the library phone directory only has a 25 GB hard drive. You can leave the defaults here or change them and click "Create". You'll see VirtualBox going to work on your disk: And when it is done, VirtualBox will return to its main console window and you will see the new VM in the list (you'll only have one in your list):

6 All the details in the right pane describe the selected VM. You can change just about anything you want by clicking the "Settings" button (or selecting it from the "Machine" menu). So, now you've created your virtual computer. A lot less painful than pulling out the credit card at Best Buy, wasn't it? We want to put Linux on it yes, we really do. But we need an installer. 11. So back to your web browser, and go here: At the bottom of the page are some mirror links where you can download. Click "US", of course. You should get a list of file links to click on, for me it looks like this right now: Click the "pclinuxos-kde iso". Note that the names change when new releases are made available. For our example we just want to be sure we pick the plainest KDE name that doesn't have "64" after "pclinuxos" and ends in ".iso" Download it somewhere.

7 12. Now comes a neat part. We don't really want to burn a DVD to just install Linux one time, do we? So let's make our virtual machine think that the ISO we just downloaded is a disk in a DVD drive. Back in VirtualBox, make sure your VM is highlighed and click "Settings" and then "Storage" in the left pane: 13. Click the round CD/DVD icon in the right pane (it probably says "Empty", but might say something else if you have a disk in your computer's CD/DVD drive): 14. Click the little disk icon in the upper right of the next screen and choose "Choose a virtual CD/DVD disk file" NOTE: also tick the "Live CD/DVD" checkbox. You can't see it here because it is under the popup menu!

8 15. You'll get the usual file-open dialog you see when using your computer. Navigate to the ISO you downloaded and select and open it. Here's me doing it: You'll see the file you chose showing up in the storage pane next to the CD/DVD icon, like this: Click "OK" 16. We are going to be using this VM as a local web server, so we'll need to be able to talk with it across a network. We don't want it accessible FROM the outside world, just to the physical host computer and other VMs on it, so we need to tweak the network settings for the VM so that it talks on a network restricted to inside your physcal computer. In the VirtualBox File menu, choose "Preferences ":

9 Click "Network" in the left pane, and then click the "Host-only Networks" tab in the right pane: Click the + icon along the right side and VirtualBox will add a network (probably called vboxnet0). We need to configure that network we just made, so click the screwdriver-shaped configuration icon:

10 Then click the "DHCP Server" tab, tick the "Enable Server" checkbox, and enter appropriate values. You can just copy the ones from my example: Server Address: Server Mask: Lower Address Bound: Upper Address Bound: If you are interested, here is what is going on: a Dynamic Host Configuration Protocol (DHCP) server is used to hand out IP addresses to computers on networks. I'll tell you more about IP addresses later, but an IP address uniquely identifies a computer on a network. Since we're going to attach our VM to our virtual host-only network, we need some way to deliver the VM an address on that network, so we're telling VirtualBox to act as a DHCP server on the host-only network. When our VM starts up, it will ask the network for an address and the DHCP server will hand it the next unused one between the lower and upper bounds. Click "OK" and then click "OK" again. You should be back to the main VirtualBox window:

11 17. Now we will tell VirtualBox that our new VM should be attached to the virtual network we just created. Go back into Settings for the VM just as you did to set up the CD/DVD drive and click on "Network" in the left pane, then click the "Adapter 2" tab: Tick the "Enable Network Adapter" checkbox to add this second network adapter to the virtual machine. Select Host-only Adapter from the "Attached to:" drop list. Click "OK"

12 18. OK! We are ready to rock. Click the big Start button (or choose Start from the Machine menu): You'll see the VM booting up in a window. It will boot off the DVD image and you'll eventually get to this screen: Use the arrow keys on your keyboard to go down and select "Install PCLinuxOS" You don't have much time to do that LiveCD is the default and will be auto-selected in a few seconds. If you don't get to it fast enough, no biggy, under the "Machine" menu select "ACPI Shutdown" at anytime to turn the power off, as in the screenshot on the next page:

13 If you do that, it'll shutdown and you'll be asked to hit <enter> when the Live CD is removed. Just hit <enter> at that point. The VM window will close when it finally powers off. Then just click the big "Start" button again to boot it (NOTE: if you didn't tick the "Live CD/DVD" checkbox noted several steps back, you'll have to go back and do the CD setup in the Storage menu again. See steps 12+). This time be ready with that arrow key!

14 This is where you should be when all is said and done: 19. Hit your Enter key. You'll see some starting up stuff happen. 20. I'm not going to do screenshots of the next couple screens. They're pretty obvious: choose a US Keyboard, then you'll be told what you are doing as if you didn't know. Just click next until you get to this one: You can actually just click "Next" on this one, too, but I wanted to say something about it. Here you are configuring the layout of the disk for your server. In our case we're going to let it install mostly in just one gigantic partition, but in some cases you may need something more specialized for example if you don't want peoples' home directories on the same file system as the web server's documents. This VM is just a play thing, so one big partition is easiest to deal with and works just fine. Click "Next"

15 21. You'll get a big red warning. We don't care we know that the disk is really the virtual disk we created when we made the VM. There is no way for the VM to get to your real disk at this point. Just click "Next". It'll prep your disk partitions. 22. Click "Next" on the next screen about removing unneeded packages, then OK. It might take it just a little while. Then it'll tell you it is installing PCLinuxOS. It won't take too long too install (about 10 minutes), but feel free to go to the bathroom, or do the really geeky thing and get some coffee and then stand there, one hand in a pocket, slouching and sipping while pointlessly watching the progress bar crawl across screen, feeling superior to the rest of mankind because you're installing Linux in a VM. Nod subtly every now and then. Isn't this exciting?

16 23. Now you'll get the boot loader option screen. The boot loader is a little program that gets installed in a special place on the disk that the computer's BIOS (that's in the hardware, in our case in virtual hardware) looks to find something to run. It doesn't care what: just loads it and transfers control. Most everyone puts a boot loader there. Black-hatted hackers like to put virus code there on other peoples' disks. In any case, it has to be very, very small. The boot loader is just enough of a program to start loading the operating system. We're going to leave defaults. Just click "Next": 24. Boot loaders general present a menu (or are capable of even if they don't). The next screen lets you configure the boot loaders menu. Defaults are fine, click "Finish": The boot loader will be installed. A few other mystery things will go on for a bit.

17 25. Click "Finish" The VM will begin to reboot. When you see this: Right-click this at the bottom of the VM window and choose "Remove disk from virtual drive" Then press your <Enter> key. The VM will reboot. The new boot loader menu will appear (you can hit Enter when it does or let it time out and auto-choose the default). PCLinuxOS is now installed and running in your VM! Congratulations! Next we've got just a couple of configuration things to do so we can login.

18 26. You'll get a couple of screens I'm not going to capture, just do what you need to: Choose your timezone (New_York), leave the default for the Date, Clock dialog. It doesn't matter if the time is wrong. 27. Got root? You will soon! Here you are setting the password for the "root" user. On a Linux (and any Unix system I've seen), root is the super-user account. It can do anything at anytime. Security components even ignore checks on it. It is all-powerful on its system. Enter a decent password. This is a play thing that won't be running all the time and is not generally accessible outside of your (real) computer, so it isn't critical that it be extremely strong, but make it strong enough just in case. Click "Next" 28. Now you need to create a general purpose user account. Whatever you want for "Login name", but I'd avoid anything but lower-case letters and numbers. Other stuff is just annoying to have to type. Spaces always cause irritation. Click "Next" AND THAT IS ALL! You are done you installed and configured Linux in a VM for general-purpose use. W00t! Now we're going to make it a web server.

19 29. Click the user you created in the previous step and enter the password you entered there. Press "Enter". You'll be logged in. Give it a bit it is doing some extra stuff this first time. Eventually it'll display a notice entitled "Please update your system!" For brevity, I'm going to leave the updating out of this document for now. Just click "OK" on that dialog. Then it'll open the Konquerer web browser to tell you to update again. Choose "Quit" from the "File" menu to get rid of that. You'll see a circle with "PC" in it in the lower-left corner of the VM window. This opens the launcher menu it's like the Start button on Windows. 30. This is Linux we like the command line. So let's get a terminal session opened up. Click the launcher button to pull up the menu, and hover over "More Applications" then over "Terminals" then select "Konsole - Terminal":

20 You'll get something like this: Everyone wants super powers, so we're going to acquire ours in the next step by becoming root. NOTE: This is where I usually start when I'm working on servers for the library: I get a remote terminal session to a server and then obtain root privileges. Then I do what needs to be done and logout. The way we are going to set up the web server on this is similar to updates and package installs that I do on an almost daily basis on my desktop (I run Linux everywhere) and on servers. 31. In the terminal you opened, enter: su 32. when prompted, enter the root password you set when you were setting up user accounts a few steps back. If you forgot it already, you are out of luck. You will have to delete your VM and start over. You can't recover the root password or change it (technically you can, but I'm not going into that, it's not simple to explain). You should now see the command prompt in red and starting with "root@localhost", something like this: 33. Every mainstream Linux distribution supports a repository of software packages built for it and provides a package manager to fetch, install, and remove them. PCLinuxOS uses APT. Other package managers include (but are not limited to) Yellowdog Updater, Modified (Yum) and Pacman. Let's freshen the list of available software packages that APT can fetch for us. Enter: apt-get update (Incidentally, if you want to apply all updates available, you'd enter apt-get upgrade at this point we're not because it'll take too long and we're impatient to get on with the next step). 34. For this exercise, I'm going to install Apache's web server. There are others, but this one is very

21 popular and found all over the internet. It is the web server running on libsytems.clemson.edu (where StaffWeb is found, among others) and on biblio.clemson.edu (where ArcihvesSpace is found, among others). Enter the following to install the Apache HTTP server: apt-get install apache-mpm-prefork The package manager will examine what you want to do and determine any software it depends on that also needs to be installed. It will present you with a summary of actions it needs to take and ask if it is OK to continue. Enter: y for "yes", and it'll go to work. It'll tell you "Done." when it is finished. 35. That installed the web server, but it hasn't been started yet. The PCLinuxOS HTTPD package installs the software and sets it up as a service that can be easily stopped and started. To start it, enter: service httpd start It should say "Starting httpd: " and eventually put "[ OK ]" out next to that. And there you go! The web server is running. You won't usually ever need to start the service manually: it is configured to start automatically when the server boots. We just had to do it this first time since we didn't reboot the server. 36. But how do you get to it? Well, this web server is not available outside the boundaries of your physical computer. Nor is there a DNS name for your VM (DNS is the Domain Name System, it's the world-wide system that turns human friendly names of servers and services, such as into computer-friendly addresses that computers need to intercommunicate). We need to find out the IP address of the VM (IP stands for Internet Protocol, and it is the intercommunication standard upon which the Internet depends. Every computer on the Internet is assigned a unique IP address like a street address for computers. For one computer to talk to another it needs to know the other's IP address). We can find out our VM's IP address by entering this command: ifconfig You should see three network interfaces listed, the externally (to your VM) accessible interface, eth1, the talk-out-only NAT interface, eth0, and the loopback interface, lo. We need to know the address assigned to the eth1 interface. You can find it after "inet adder:" in the list of information displayed: In this case, the address of this VM is Find the address of yours and make a note of it. NOTE: the address assigned to your VM may be different depending on how you set

22 up the DHCP server in VirtualBox's host-only network configuration! 37. Now let's see if that web server is running properly. Back on your host computer (not in your VM), open your favorite web browser and put " followed by the IP address you noted in the previous step in the address bar. I would enter this for my example: You will get a page that says "The Server is alive and working." If you didn't, something went wrong somewhere, but if you did, congratulations! You just successfully installed your first web server! 38. The web server serves content from what is called its "Document Root". Most are configured by default to serve up whatever is in a file called "index.html" if no file is provided in the request URI (the request URI is what you enter in a browser address bar). Back in your VM in the console where you entered all the commands to install the web server, enter this: ls /var/www/html That gives a listing of the files and directories in your web server's document root. You'll see index.html in there. If you are really interested, enter: cat /var/www/html/index.html to see the contents of index.html. Near the bottom of the file listing, you'll see the phrase displayed in the test request you viewed, "The Server is alive and working." The rest of the gobbledygook is HTML markup. If you don't know what HTML is, it is what gives web pages their basic structure and look. You can learn all about HTML here: along with numerous other technologies used in building web pages and applications. For now, though, you are going to build a very simple web page. All web browsers I've ever seen will display plain old text, so you can make a working web page with no HTML in it. That's what you are going to do now. 39. Still in your VM terminal session, enter this: echo "The quick brown fox jumped over the lazy systems programmer." > /var/www/html/qbf.html This will put the line "The quick brown fox jumped over the lazy systems programmer." into the file qbf.html in the web server's document root. 40. Now, back in your "real" computer's web browser, put "/qbf.html" on the end of the test address you entered before. For my example, it is like this: Not surprisingly, you should see the quick brown fox phrase display in your web browser. Congratulations are in order again: you've made a web page!

23 41. The last thing you need to know how to do is shutdown the server. There are (more than) two ways to do it, but I'll let you pick. You can do it the GUI way by clicking the "PC" button to popup the launcher menu, and then choose "Leave" and then "Shut down": OR you can enter this in the console while still root: shutdown -h now like this: Either way, the VM will shutdown and "power off". Now anytime you want to play around with Linux, learn some web development, or take over the world, you can just start VirtualBox, Start your VM, login and have at it! Have fun!