Inception

This project was developed for 42 school. For comprehensive information regarding the requirements, please consult the PDF file in the subject folder of the repository. Furthermore, I have provided my notes and a concise summary below.

+ keywords: docker
+ set up small infrastructure composed of different services
+ docker virtualises the operating system, lightweight (only one kernel) and portable containers
+ move from monolith apps to a service oriented architecture
+ development - testing - production

Mindmap (shinckel, 2024)

High-level Overview

Each Docker image must have the same name as its corresponding service. Each service has to run in a dedicated container. For performance matters, the containers must be built either from the penultimate stable version of Alpine or Debian. The Dockerfiles must be called in your docker-compose.yml by your Makefile. Write your own Dockerfiles, one per service.

You then have to set up: • A Docker container that contains NGINX with TLSv1.2 or TLSv1.3 only. • A Docker container that contains WordPress + php-fpm (it must be installed and configured) only without nginx. • A Docker container that contains MariaDB only without nginx. • A volume that contains your WordPress database. • A second volume that contains your WordPress website files. • A docker-network that establishes the connection between your containers. Your containers have to restart in case of a crash.

-| srcs/
---| docker-compose
---| .env
---| requirements/
----| mariadb/ (database)
-----| tools/
------| db_start.sh
------| mysqld.conf
------| wordpress.sql
-----| Dockerfile
----| nginx/ (web server)
-----| conf/
-----| Dockerfile
----| wordpress
-----| conf/
-----| tools/
-----| Dockerfile
| Makefile

Relationship Between MariaDB, Nginx, and WordPress

• MariaDB: This container runs the MariaDB database server, which stores all the data for your WordPress site.
• Nginx: This container runs the Nginx web server, which serves as a reverse proxy to forward HTTPS requests to the WordPress container.
• WordPress: This container runs WordPress with PHP-FPM, which processes PHP code and generates dynamic content for the website. -All services run in separate containers, connected via a Docker network, with volumes for persistent storage. The docker-compose.yml and Makefile automate the setup and management of these containers.

Using network: host or --link or links: is forbidden. The network line must be present in your docker-compose.yml file. Your containers musn’t be started with a command running an infinite loop. Thus, this also applies to any command used as entrypoint, or used in entrypoint scripts. The following are a few prohibited hacky patches: tail -f, bash, sleep infinity, while true.

- apt-get install docker-engine (debian/ubuntu)
- docker toolbox (download to mac, creates a VM for running docker)

- docker info (how many images)
- docker version
- docker run (if doesn't have an image locally, it talks to dockerHub remotelly)
- time docker run hello-world (how much time takes to run the container in ms)
- docker run -d -P [image-name] (locally or remotely, - flags tell how to run the container, P is for mapping a random port on the host to a specified port within the container itself)

- docker ps (you should see the container running)
- access and visualize the deployed application through [ip number]/port

- docker build -t name/demo:v1 . (build and name the image, add a tag e.g. v1)
- docker run -d -P name/demo:v1 (run a container)

- docker build -t name/demo:v2 . (edit the source file and build another image, changing the version tag. it will use the cache and build super fast)
- docker images

- share container with friends in dockerHub -> docker push name/demo:v2

- docker logs image-name
- docker rm image-name
- docker ps -a (list all containers, including the ones that have stopped)
- docker stop container-name
- docker network ls (list current docker network)
- driver: network type

# A basic Apache+PHP Image 
FROM ubuntu:12.04

MAINTAINER Nicola Kabar version: 0.1

RUN apt-get update && apt-get install -y apache2

RUN apt-get install -y php5

ENV APACHE_RUN_USER www-data
ENV APACHE_RUN_GROUP www-data
ENV APACHE_LOG_DIR /var/log/apache2

RUN rm -rf /var/www/*
ADD index.php /var/www/

EXPOSE 80

CMD ["/usr/sbin/apache2", "-D", "FOREGROUND"]

$ docker pull centos
$ docker run -d -t --name myfirstcontainer centos
$ docker ps
> CONTAINER ID   IMAGE     COMMAND       CREATED         STATUS         PORTS     NAMES
> abd188b5d3a4   centos    "/bin/bash"   3 seconds ago   Up 2 seconds             myfirstcontainer
$ docker exec -it myfirstcontainer bash
[root@abd188b5d3a4 /]# --> you are inside the container, connected to bash shell

$ docker pull alpine
$ docker run -d -t --name mysecondcontainer alpine
$ docker exec -it mysecondcontainer sh
> / #
> exit

$ docker run -itd --rm --name thor busybox (rm remove container after running it)
> CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS     NAMES
> a3e817b291a6   nginx     "/docker-entrypoint.…"   20 seconds ago   Up 19 seconds   80/tcp    spiderman
> 1b41d844c330   busybox   "sh"                     10 minutes ago   Up 10 minutes             batman
> 6b75aab91b64   busybox   "sh"                     10 minutes ago   Up 10 minutes             thor
$ ip address show (it will show three new networks, besides loopback, broadcast and docker)
$ bridge link
> 29: vethd80e00e@if28: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master docker0 state forwarding priority 32 cost 2 
> 31: vethb13694d@if30: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master docker0 state forwarding priority 32 cost 2 
> 33: vethc69260d@if32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master docker0 state forwarding priority 32 cost 2
$ docker inspect bridge
$ docker run -itd --rm -p 80:80 --name spiderman nginx
$ docker ps
> CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                               NAMES
> f7cdd36128cf   nginx     "/docker-entrypoint.…"   2 minutes ago    Up 2 minutes    0.0.0.0:80->80/tcp, :::80->80/tcp   spiderman

References:

Virtual Machine (VM) vs Docker
What are Microservices?
Containerization Explained
Contain Yourself: An Intro to Docker and Containers by Nicola Kabar and Mano Marks
What is Docker? watch demo from minute 24
Apache+PHP Dockerfile Demo

Concepts

Task	Prototype	Description
VM && docker	abstraction layer	Software is used to create an abstraction layer(virtualization). VM lifecycle is measured in months. Container lifecycle is measured in seconds.
Virtual machine	Hypervisor	Virtual machine emulates the physical computer, managing the allocation of resources (virtual hardware, virtual CPU, guest OS, etc) from a single physical host. Benefits: diverse OS, isolation/separated kernel and OS, set environment for running legacy applications. Downsides: deploy a separated guest OS everytime you create a VM, binary library, etc, even for a small application. It takes a lot of resources. host OS - hypervisor - guest OS
Containerization	Operating System virtualization	Instead of hardware level, it is an OS virtualization abstraction level. Each application lightweight, isolated, runnable, and portable. New way to package EVERYTHING that an app needs to run, regardless of running it in a local or production environment (a.k.a no matter which underlying infrastructure). Example: if you developed your app locally, using the Docker platform, expect it to be successfully deployed. No matter what is the underlying infrastructure. As long as there is a docker engine running on the other side (operation infrastructure using any cloud: AWS, Google, Microsoft, open stack cloud) your application is going to be successfylly deployed there. Running with the exact same behaviour you architectured it to be. Watch Why You Need to Learn Containerization.
Docker	Containerization built around client server architecture	Open source platform that uses containerization. Package of application and dependencies into lightweight containers. An individual container has only the application and its libraries and dependencies. Benefits: Microservices, speed development/deployment/scale up, CI/CD pipelines, resource efficiency/small footprint. host OS - runtime engine - don't worry about guest OS - container/libs. Shared resources: if it is not being used by the service, share resources with the other containers.
Docker engine	orchestrating containers	Creating, running and orchestrating containers (building - shipping - deploying - managing). Interact with host kernel to allocate resources and force isolation between containers. Control groups, namespaces: restrict access and visibility to others. It is built around HTTP REST API.
Docker image	executable packages	Runtime code/libraries/tools/lightweight standalone, static files. Executable packages, which are built using Dockerfile. TEMPLATE in which containers are built from. READ-ONLY, IMMUTABLE.
Docker container	isolated environment	Instances of the docker images, running in the docker engine. Isolated in a self-sufficient environment. READ-WRITE LAYER. Copy-on-write(COW): if you are not making extra changes in the container, it is not going to take extra space, so it is utilizing what is already there.
Chicken and egg	references	All containers are born from images and images are created from commited containers. Dockerfile can be understood as the first step of the process, automated by Docker itself.
Dockerfile	manifest	Instructions for building the images. A manifest describes de container, in docker world it would be the Dockerfile (but please remember that containerization concept was created in 2008 before docker existed - released in 2013). manifest - image - container => for every line it creates de container - executes that line - commits container to a new image - uses it for all subsequent operations
Microservices	modular application architecture	Every app function is its own service running in a container. Services communicate via API, in a modular and more flexible way: you can use different languages/frameworks, deploy it fast, if one service fails/crash the rest continue to run in an independent way. It is also possible to add capability to a specific service that is more required e.g. payment service for a webside selling ticket to the final game.
Monolith	rigid application architecture	You are dependent on decisions made in the past(language/framework, libraries). Over time it is difficult to grow: what are the dependencies and relationship between the different parts of the software? For deploying it you will have to shut down the app and deploy everything again (sometimes a second instance of the whole application), it takes a long time. SHIFTED FROM DEPLOYING EVERY MONTH TO CONTINUOS INTEGRATION AND CONTINUOS DEVELOPMENT.
bare metal	bare machine	Refers to a computer executing instructions directly on logic hardware without an intervening operating system.
REST API
Check docker in your VM	docker run -it ubuntu bash	The purpose of this command is to start a new Ubuntu container and provide you with an interactive Bash shell inside that container.
Network	80:80 host:dockercontainer	Container share the same configs as the host e.g. ip address, or port forwarding e.g. into the host OS stack, meaning: host port 8888 inside the app could be running in port 80.
Bridge network	Default bridge docker 0 : virtual bridge interface	Each app has its own ip address (and could share with other containers) ip address show. Change network from NAT to Bridge Adapter. Downside: manually expose ports, otherwise you can't access services directly e.g. website. docker run -itd --rm -p 80:80 --name spiderman nginx. Each container has its own ip address. Each one has a copy of /etc/resolv.conf.
Volumes		Each app has its own filesystem, but you can map files from host directly to your app (keep data, destroy containers). E.g. shared container volumes, doesn't run app only share data.
Clean cache	sudo apt-get clean sudo du -sh /* pipe sort -h
User defined bridge	docker network create name	docker network ls ip address show hostname -I will show a new network bridge. docker run -itd --rm --network [network name] --name [container name] [image name] bridge link docker inspect [network name] new interfaces will be tied to the virtual bridge created. Why should I do it? ISOLATION, protected from the default network. Check using ping, I can ping the new virtual bridge by name ping [network name].
Host network	docker run -itd --rm --network host --name [container name] [image name]	Moved next to the host, everything is shared with the host e.g. ip address, ports, etc. Downside: no isolation.
Mac VLAN
Remove cache	sudo apt-get clean	Remove the package cache to free up space. Remove unused Docker containers, volumes, and networks to free up space docker container prune -f docker volume prune -f docker network prune -f. Check for large log files and remove them sudo rm -rf /var/log/*.log
Verify port mapping	sudo netstat -tuln [pipe] grep 80	tcp 0 0 0.0.0.0:80 0.0.0 0:* LISTEN
Check if services are network connected	docker network inspect my_custom_network	It will return an object containing connected services.
Useful commands	troubleshooting	docker-compose -p srcs restart nginx docker-compose -p srcs ps docker-compose -p srcs logs wordpress docker exec -it inception-nginx apt-get install -y telnet docker exec -it inception-nginx telnet wordpress 9000 sudo systemctl status docker

Ensure the directories have the correct permissions so that Docker can access them: sudo chown -R ubuntu:ubuntu /home/ubuntu/data/wp_data sudo chown -R ubuntu:ubuntu /home/ubuntu/data/db_data sudo chmod -R 755 /home/ubuntu/data/wp_data sudo chmod -R 755 /home/ubuntu/data/db_data

docker inspect 4dad940eafe4 | grep -i env

check ssl connection openssl s_client -connect shinckel.42.fr:443

Since UFW is inactive, your firewall isn't blocking any connections. sudo ufw status

shinckel@inceptionVirtualMachine:~/Documents/inception$ sudo docker exec -it 
inception-mariadb env
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=3cf14098864a
TERM=xterm
WORDPRESS_ADMIN_PASSWORD=adminpass
WORDPRESS_ADMIN_USER=admin
MYSQL_DATABASE=wordpress
MYSQL_ROOT_PASSWORD=superpass
WORDPRESS_TITLE=My WordPress Site
DOMAIN_NAME=shinckel.42.fr
WORDPRESS_URL=http://shinckel.42.fr
WORDPRESS_ADMIN_EMAIL=admin@shinckel.42.fr
CONTAINER_NAME=inception
MYSQL_HOSTNAME=mariadb
WORDPRESS_DEBUG=false
MYSQL_USER=shinckel
WORDPRESS_TABLE_PREFIX=wp_
MYSQL_PASSWORD=pass
GOSU_VERSION=1.17
LANG=C.UTF-8
MARIADB_VERSION=1:11.5.2+maria~ubu2404
HOME=/root

run docker with no sudo sudo usermod -aG docker $USER

mariadb -u root -p show DATABASES; USE inception; SHOW TABLES;

SELECT ID, post_title, post_date, post_status FROM wp_posts WHERE post_type = 'post' AND post_status = 'publish';

SELECT comment_ID, comment_post_ID, comment_content, comment_date, comment_approved FROM wp_comments WHERE comment_post_ID = 1;

SELECT ID, user_login, user_email, user_registered, display_name FROM wp_users;