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System administration for junior devs: Setting up a virtual server with Vagrant
When you’re learning about system administration, it is helpful to have a private server to muck around on so that your mistakes do not affect users. Fortunately, you can use a tool called Vagrant to easily create virtual servers on your development machine. This tutorial requires Vagrant, so you will need to follow these instructions if you do not have it already (it is pretty easy). You will also need VirtualBox.
This blog post aims to help developers create a virtual server while also explaining what, exactly, that means.
1. Creating a clean virtual server
For this tutorial, I have predefined some very vanilla Vagrant settings to get things started. To grab those, run git clone https://github.com/handlers/servers.git.
Now cd into that directory. ls and you’ll see that the repository has a Vagrantfile which contains details about the server that Vagrant is going to create. If you poke around that Vagrantfile and ctrl + f for “config.vm.box,” you should see a line that looks like this: config.vm.box = "ubuntu/trusty64". This tells Vagrant that our server should come preloaded with the Trusty release of the Ubuntu operating system. You should also note that this Vagrantfile specifies a private IP address of 192.168.33.11.
2. Creating your virtual server
We will now use Vagrant to create a virtual server on your computer. Make sure you’re in the project directory you cloned from GitHub and run vagrant up. (It may take a while to download the Ubuntu base image.1) Eventually your terminal should spit out something like this:
==> default: Machine booted and ready!
==> default: Checking for guest additions in VM...
==> default: Configuring and enabling network interfaces...
==> default: Mounting shared folders...
3. What it means to have a virtual server
When you run vagrant up, you create something that walks and talks like a real server, but it is actually running within your own computer. For our purposes, it is important that the virtual server is networked. We can prove it by pinging the IP referenced in the Vagrantfile (192.168.33.11).
$ ping 192.168.33.11
PING 192.168.33.11 (192.168.33.11): 56 data bytes
64 bytes from 192.168.33.11: icmp_seq=0 ttl=64 time=0.385 ms
^C
--- 192.168.33.11 ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.385/0.385/0.385/0.000 ms
As you can see, we are getting packets back from the IP address we just created.
Vagrant also preloads the machine with a user named vagrant, and you can ssh into the machine as this user. Try running vagrant ssh from within the project directory.2 You should see a prompt like this:
vagrant@vagrant-ubuntu-trusty-64:~$
It allows you to do everything you can do on a regular server, from checking out the machine’s OS to poking around its directory structure.
“`
vagrant@vagrant-ubuntu-trusty-64:~$ uname -a
Linux vagrant-ubuntu-trusty-64 3.13.0-39-generic #66-Ubuntu SMP Tue Oct 28 13:30:27 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
vagrant@vagrant-ubuntu-trusty-64:~$ pwd
/home/vagrant
vagrant@vagrant-ubuntu-trusty-64:~$ ls /
bin dev home lib lost+found mnt proc run srv tmp vagrant vmlinuz
boot etc initrd.img lib64 media opt root sbin sys usr var
“`
You now have a virtual Ubuntu server running on your computer, complete with ssh access. cd / and take a little time to check out what’s going on. It might be helpful to check out this Wikipedia article on Unix’s normal directory structure. Many, many websites run on computers that have directories laid out like this. Don’t worry about messing some part of your server up — creating a fresh image is as easy as bringing down your existing server with vagrant destroy and then running vagrant up again. Remember that these commands (vagrant ___) should be issued from your computer, not from within the virtual machine.
You have now completed the first step in understanding how your server fields Web requests, creating a very basic, networked virtual server. You are controlledly replicating the Internet on your development machine. Stay tuned for part III, in which we configure our server to handle HTTP requests with NGINX.
Extra credit
If you really want to get down into the guts of what’s going on, try sshing into your virtual server and running tcpdump -i any icmp[icmptype] == 8 to see what happens when you ping it. It is pretty cool!
1 The wait is more bearable when you realize you are basically downloading a whole computer!
2 It is worth noting that you did not run your system’s standard ssh command, but rather a Vagrant utility called ssh which opens a shell session on the virtual machine. You can, however, also run ssh [email protected] with password vagrant.
The Sunlight Foundation is a non-profit, nonpartisan organization that uses the power of the Internet to catalyze greater government openness and transparency, and provides new tools and resources for media and citizens, alike.
Source: http://sunlightfoundation.com/blog/2015/05/12/system-administration-for-junior-devs-setting-up-a-virtual-server-with-vagrant/
