0x0D. Web stack debugging #0

Concepts

For this project, we expect you to look at these concepts:

Background Context

The Webstack debugging series will train you in the art of debugging. Computers and software rarely work the way we want (that’s the “fun” part of the job!).

Being able to debug a webstack is essential for a Full-Stack Software Engineer, and it takes practice to be a master of it.

In this debugging series, broken/bugged webstacks will be given to you, the final goal is to come up with a Bash script that once executed, will bring the webstack to a working state. But before writing this Bash script, you should figure out what is going on and fix it manually.

Let’s start with a very simple example. My server must:

have a copy of the /etc/passwd file in /tmp
have a file named /tmp/isworking containing the string OK

Let’s pretend that without these 2 elements, my web application cannot work.

Let’s go through this example and fix the server.

docker run -d -ti ubuntu:14.04

			Unable to find image 'ubuntu:14.04' locally
			14.04: Pulling from library/ubuntu
			34667c7e4631: Already exists
			d18d76a881a4: Already exists
			119c7358fbfc: Already exists
			2aaf13f3eff0: Already exists
			Digest: sha256:58d0da8bc2f434983c6ca4713b08be00ff5586eb5cdff47bcde4b2e88fd40f88
			Status: Downloaded newer image for ubuntu:14.04
			76f44c0da25e1fdf6bcd4fbc49f4d7b658aba89684080ea5d6e8a0d832be9ff9
		

docker ps

			CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
			76f44c0da25e ubuntu:14.04 "/bin/bash" 13 seconds ago Up 12 seconds infallible_bhabha
		

docker exec -ti 76f44c0da25e /bin/bash

			root@76f44c0da25e:/# ls /tmp/
			root@76f44c0da25e:/# cp /etc/passwd /tmp/
			root@76f44c0da25e:/# echo OK > /tmp/isworking
			root@76f44c0da25e:/# ls /tmp/
			isworking passwd
			root@76f44c0da25e:/#
		

Then my answer file would contain:

cat answerfile

			#!/usr/bin/env bash
			# Fix my server with these magic 2 lines
			cp /etc/passwd /tmp/
			echo OK > /tmp/isworking
		

Note that as you cannot use interactive software such as emacs or vi in your Bash script, everything needs to be done from the command line (including file edition).

Installing Docker

If you would like to have Docker so that you can experiment with it and/or solve this problem locally, you can install it on your machine, your Ubuntu 14.04 VM, or your Ubuntu 16.04 VM if you upgraded.

Mac OS
Windows
Ubuntu 14.04 LTS (Note that Docker for Ubuntu 14 is deprecated and you will have to make some adjustments to the instructions when installing)
Ubuntu 16.04

More Info

Resources

curl

Requirements

General

Allowed editors: vi, vim, emacs
All your files will be interpreted on Ubuntu 14.04 LTS
All your files should 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 scripts must pass Shellcheck without any error
Your Bash scripts must run without error
The first line of all your Bash scripts should be exactly #!/usr/bin/env bash
The second line of all your Bash scripts should be a comment explaining what is the script doing

Tasks

0. Give me a page!

Be sure to read the Docker concept page

In this first debugging project, you will need to get Apache to run on the container and to return a page containing Hello Holberton when querying the root of it.

Example:

docker run -p 8080:80 -d -it holbertonschool/265-0

47ca3994a4910bbc29d1d8925b1c70e1bdd799f5442040365a7cb9a0db218021

docker ps

				CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
				47ca3994a491 holbertonschool/265-0 "/bin/bash" 3 seconds ago Up 2 seconds 0.0.0.0:8080->80/tcp
				vigilant_tesla
			

curl 0:8080

curl: (52) Empty reply from server

Here we can see that after starting my Docker container, I curl the port 8080 mapped to the Docker container port 80, it does not return a page but an error message. Note that you might also get the error message curl: (52) Empty reply from server.

curl 0:8080

Hello Holberton

After connecting to the container and fixing whatever needed to be fixed (here is your mission), you can see that curling port 80 return a page that contains Hello Holberton. Paste the command(s) you used to fix the issue in your answer file.

Repo

Repo:
- GitHub repository: alx-system_engineering-devops
- Directory: 0x0D-web_stack_debugging_0
- File: 0-give_me_a_page

Last modified: 05 September 2024