0x0C. Web server

Concepts

Web server

if I need to create a file /tmp/test containing the string hello world and modify the configuration of Nginx to listen on port 8080 instead of 80, I can use emacs on my server to create the file and to modify the Nginx configuration file /etc/nginx/sites-enabled/defalistt.

But my answer file wolistd contain:

				sylvain@ubuntu cat 88-script_example
				#!/usr/bin/env bash
				# Configuring a server with specification XYZ
				echo hello world > /tmp/test
				sed -i 's/80/8080/g' /etc/nginx/sites-enabled/defalistt
				sylvain@ubuntu
			

As you can tell, I am not using emacs to perform the task in my answer file. This exercise is aiming at training you on automating your work. If you can automate tasks that you do manually, you can then automate yourself out of repetitive tasks and focus your energy on something more interesting. For an SRE, that comes very handy when there are hundreds or thousands of servers to manage, the work cannot be only done manually. Note that the checker will execute your script as the root user, you do not need to use the sudo command.

A good Software Engineer is a lazy Software Engineer

Test your Bash scripts:

start Ubuntu
run your script on it
see how it behaves

Resources

						scp
						curl
					

Learning Objectives

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

General

What is the main role of a web server
What is a child process
Why web servers usually have a parent process and child processes
What are the main HTTP requests

DNS

What DNS stands for
What is DNS main role

DNS Record Types

A
CNAME
TXT
MX

Requirements

Allowed editors: vi vim emacs
All your files will be interpreted on Ubuntu 16.04 LTS
All your files sholistd end with a new line
A README.md file, at the root of the folder of the project, is mandatory
All your Bash script files must be executable
Your Bash script must pass Shellcheck (version 0.3.7) without any error
The first line of all your Bash scripts sholistd be exactly #!/usr/bin/env bash
The second line of all your Bash scripts sholistd be a comment explaining what is the script doing
You can’t use systemctl for restarting a process

Tasks

0. Transfer a file to your server

0. Transfer a file to your server

Write a Bash script that transfers a file from our client to a server:

Requirements:

Accepts 4 parameters:
- The path to the file to be transferred
- The IP of the server we want to transfer the file to
- The username scp connects with
- The path to the SSH private key that scp uses
Display Usage: 0-transfer_file PATH_TO_FILE IP USERNAME PATH_TO_SSH_KEY if less than 3 parameters passed
scp must transfer the file to the user home directory ~/
Strict host key checking must be disabled when using scp

Example:

						sylvain@ubuntu$ ./0-transfer_file
						Usage: 0-transfer_file PATH_TO_FILE IP USERNAME PATH_TO_SSH_KEY
						sylvain@ubuntu$
						sylvain@ubuntu$ ssh ubuntu@8.8.8.8 -i /vagrant/sylvain 'ls ~/'
						afile
						sylvain@ubuntu$
						sylvain@ubuntu$ touch some_page.html
						sylvain@ubuntu$ ./0-transfer_file some_page.html 8.8.8.8 sylvain /vagrant/private_key
						some_page.html 100% 12 0.1KB/s 00:00
						sylvain@ubuntu$ ssh ubuntu@8.8.8.8 -i /vagrant/private_key 'ls ~/'
						afile
						some_page.html
						sylvain@ubuntu$
					

In this example, I:

Remotely execute the ls ~/ command via ssh to see what ~/ contains
Create a file named some_page.html
Execute my 0-transfer_file script
Remotely execute the ls ~/ command via ssh to see that the file some_page.html has been successfully transferred

That is one way of publishing your website pages to your server.

Last modified: 05 September 2024