Merge pull request #10 from PoCInnovation/soft/day04

Software pool day 04

Software/day04/1 - Docker/README.md

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+# PoC Software Pool 2024 - Day 04 - Docker
+
+**Day purposes**
+
+✔️ Understand DevOps interests.
+
+✔️ Learn the basics of Docker.
+
+✔️ Create a simple image.
+
+✔️ Deploy a complete stack with `docker compose`.
+
+## Introduction
+
+When it's time to deploy an application, you will face various problems:
+- How scale on various servers?
+- How build your app for several architectures?
+- How manage dependencies and linked services that work with your app?
+
+For instance, if you want to deploy a simple application composed of a web 
+server, a frontend and a database, you will need to install all the
+required dependencies in the server, maybe update root config and create
+system services to automatically restart it on fail, manage volumes and so on...
+
+You've understood it, manually manage a stack is complex and painful.<br>
+This is why Docker exist, with it you can easily package your application
+into containers that you can manage independently or together.
+
+This dynamic follows the way of [DevOps](https://aws.amazon.com/devops/what-is-devops/),
+it's a philosophy and set of practices to improve the delivery process from
+build to release and monitoring.
+
+Here's a simple schema of the devops workflow:
+
+![devops workflow](../../.github/assets/software_devops_workflow.jpeg)
+
+This subject is focused on docker and containers building & management. It's
+one the most important part of DevOps.
+
+## Step 0 - Setup
+
+Please refer to the [SETUP.md](./SETUP.md) file.
+
+## Step 1 - Dockerfile
+
+Dockerfile is the first piece to containerize your application.<br>
+The purpose is to create an image of your application to make it easily
+deployable 😃
+
+This will help you to avoid installing the application directly on the
+computer and having dependencies issues.<br>
+With an image, you can't have any of these problems, it's self deployable and
+everything is already installed in it, you just have to run it with
+`docker run <image>`.
+
+Let's create an image of the API you made yesterday 🚀
+
+First, in your pool repository, in the folder `day04`, create a folder `docker`.
+
+```shell
+mkdir -p day04/docker
+```
+
+Now you can create a directory `step1`, copy-paste yesterday API
+sources and create a file [`Dockerfile`](https://docs.docker.com/engine/reference/builder/).
+
+Your `Dockerfile` must execute the following set:
+- Pull the latest [`alpine`](https://nickjanetakis.com/blog/the-3-biggest-wins-when-using-alpine-as-a-base-docker-image)
+image of your language.
+- [Expose](https://docs.docker.com/engine/reference/builder/#expose) port `8080`
+- Install dependencies
+- Set the [environment variable](https://docs.docker.com/engine/reference/builder/#env)
+`HELLO_MESSAGE` to `docker`
+- Build the API
+- Set the entrypoint to start the server when running the image.
+
+> ⚠️ Be careful to the listening API host.
+
+> Take a look at those [good practices](https://docs.docker.com/develop/develop-images/dockerfile_best-practices/) 😉
+
+## Step 2 - Docker compose
+
+In the previous step, you saw how to put your application in a container,
+it's time to go further: you will manage multiple containers with
+[docker compose](https://docs.docker.com/compose/).
+
+Create a directory `step2`:
+
+```shell
+mkdir -p step2
+```
+
+The purpose is to manage a fullstack application within containers.<br>
+This [application](./resources) is composed of:
+- a [PostgreSQL database](https://www.postgresql.org) (to run in a container)
+- a [NestJS](https://nestjs.com) API
+- a [React](https://reactjs.org) web application
+
+Here's a simple schema of the application architecture:
+
+![front-back-db](../../.github/assets/software-micro-services.png)
+
+### Lay the foundations
+
+In the directory `step2`, copy the [frontend](./resources/frontend.zip)
+and [backend](./resources/backend.zip) zips and extract them.
+
+You should end up with the following architecture:
+
+```shell
+tree -d
+# .
+# ├── backend
+# │   ├── src
+# │   │   └── notes
+# │   └── test
+# └── frontend
+#     ├── cypress
+#     ├── public
+#     └── src
+#         ├── components
+#         │   ├── List
+#         │   ├── Task
+#         │   └── TaskForm
+#         ├── dto
+#         └── services
+#
+# 13 directories
+```
+
+### Dockerfiles
+
+As you may notice, there is no `Dockerfile` in `frontend` or `backend`.<br>
+You figured out, you will need to create images for the `frontend` and the `backend`.<br>
+In each directory, create a `Dockerfile` and write a set of instructions to
+make it work.
+
+> 💡 You will need to test and understand how each program work to containerize it.<br>
+> Google is also your best friend, as a DevOps engineer it's common to
+> work on multiple stack without necessarily being an expert on them.
+
+### Compose
+
+[Docker compose](https://docs.docker.com/compose/compose-file/) aims to
+orchestrate services. It will help you a lot when you need to deploy
+multiple [microservices](https://aws.amazon.com/microservices/).
+
+Your `docker-compose` file must be composed of:
+
+3 services:
+- backend: run the `backend` image
+- frontend: run the `frontend` image
+- database: run the `postgres` image
+
+1 network:
+- backend: link database & backend in a private network
+
+1 volume:
+- db-data: store database permanent data
+
+To complete this step, you'll need to use all the knowledge acquired during
+previous day. It will be important to set an environment to correctly
+configure the database, backend and frontend in the `docker-compose`.
+
+> Don't forget to exposed ports and link your services 😄
+
+> This step is voluntarily complex to make you search and understand
+> by yourself, this is what real DevOps engineers do 🚀
+
+## Additional resources
+
+- [Optimize your Dockerfile](https://medium.com/@tonistiigi/faster-multi-platform-builds-dockerfile-cross-compilation-guide-part-1-ec087c719eaf)
+- [Buildkit, the future of docker build](https://github.com/moby/buildkit)
+- [Scale to the moon with Kubernetes](https://kubernetes.io)
+- [Create a Swarm of container with DockerSwarm](https://docs.docker.com/engine/swarm/)
+- [Improve your stack deployment with Helm](https://helm.sh)
+- [A GUI to manage your container: LazyDocker](https://github.com/jesseduffield/lazydocker)
+- [Infra as code with Terraform](https://registry.terraform.io)
+
+<h2 align=center>
+Organization
+</h2>
+<br/>
+<p align='center'>
+    <a href="https://www.linkedin.com/company/pocinnovation/mycompany/">
+        <img src="https://img.shields.io/badge/LinkedIn-0077B5?style=for-the-badge&logo=linkedin&logoColor=white" alt="LinkedIn logo">
+    </a>
+    <a href="https://www.instagram.com/pocinnovation/">
+        <img src="https://img.shields.io/badge/Instagram-E4405F?style=for-the-badge&logo=instagram&logoColor=white" alt="Instagram logo"
+>
+    </a>
+    <a href="https://twitter.com/PoCInnovation">
+        <img src="https://img.shields.io/badge/Twitter-1DA1F2?style=for-the-badge&logo=twitter&logoColor=white" alt="Twitter logo">
+    </a>
+    <a href="https://discord.com/invite/Yqq2ADGDS7">
+        <img src="https://img.shields.io/badge/Discord-7289DA?style=for-the-badge&logo=discord&logoColor=white" alt="Discord logo">
+    </a>
+</p>
+<p align=center>
+    <a href="https://www.poc-innovation.fr/">
+        <img src="https://img.shields.io/badge/WebSite-1a2b6d?style=for-the-badge&logo=GitHub Sponsors&logoColor=white" alt="Website logo">
+    </a>
+</p>
+
+> 🚀 Don't hesitate to follow us on our different networks, and put a star 🌟 on `PoC's` repositories.

Software/day04/1 - Docker/SETUP.md

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+# Setup - [Docker]
+
+Let's install [Docker](https://docs.docker.com/engine/install/fedora/)
+engine with his CLI and [docker compose](https://docs.docker.com/compose/install/linux).
+
+## Install [Docker]
+
+> ⚠️ The following steps are made for fedora (your default dump). <br>
+> If you use another OS, please, follow this [documentation](https://docs.docker.com/engine/install/)
+
+#### Clean up
+
+Let's start by removing old unused dependencies
+
+```shell
+sudo dnf remove docker                   \
+                docker-client            \
+                docker-client-latest     \
+                docker-common            \
+                docker-latest            \
+                docker-latest-logrotate  \
+                docker-logrotate         \
+                docker-selinux           \
+                docker-engine-selinux    \
+                docker-engine
+```
+
+#### Installation
+
+We can now install docker engine and the compose plugin:
+
+```shell
+# Add docker repository to your package manager
+sudo dnf -y install dnf-plugins-core
+sudo dnf config-manager --add-repo https://download.docker.com/linux/fedora/docker-ce.repo
+
+# Install Docker
+sudo dnf install docker-ce docker-ce-cli containerd.io
+
+# Install docker compose
+sudo dnf install docker-compose-plugin
+
+### Start Docker
+
+After installing all the dependencies, start docker engine:
+
+```shell
+# Start docker service
+sudo systemctl start docker
+
+# Optional: Automatically start it when on computer start
+sudo systemctl enable docker
+```
+
+The last thing to do for a seamless experience is to [enable the use of Docker without a root user](https://docs.docker.com/engine/install/linux-postinstall/#manage-docker-as-a-non-root-user): 
+
+```shell
+# Add current user to docker group to use docker CLI without sudo
+sudo groupadd docker
+sudo usermod -aG docker $USER
+
+# Logout from your user session or restart your computer
+```
+
+#### Troubleshooting
+
+If you are on Fedora 31+, you will certainly meet this issue:
+
+```shell
+docker: Error response from daemon: cgroups: cannot found cgroup mount destination: unknown.
+```
+
+If that happens, read this [issue](https://github.com/docker/for-linux/issues/219)
+and try the fixes in it.
+
+> If you still struggle, don't hesitate to ask the staff to help you 😄
+
+## Check your installation
+
+You can verify that everything goes well by running a [`hello-world`](https://hub.docker.com/_/hello-world)
+container.
+
+You should have the following output:
+
+```shell
+docker run hello-world
+# Unable to find image 'hello-world:latest' locally
+# latest: Pulling from library/hello-world
+# 2db29710123e: Pull complete 
+# Digest: sha256:18a657d0cc1c7d0678a3fbea8b7eb4918bba25968d3e1b0adebfa71caddbc346
+# Status: Downloaded newer image for hello-world:latest
+# 
+# Hello from Docker!
+# This message shows that your installation appears to be working correctly.
+# 
+# To generate this message, Docker took the following steps:
+#  1. The Docker client contacted the Docker daemon.
+#  2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
+#     (amd64)
+#  3. The Docker daemon created a new container from that image which runs the
+#     executable that produces the output you are currently reading.
+#  4. The Docker daemon streamed that output to the Docker client, which sent it
+#     to your terminal.
+# 
+# To try something more ambitious, you can run an Ubuntu container with:
+#  $ docker run -it ubuntu bash
+# 
+# Share images, automate workflows, and more with a free Docker ID:
+#  https://hub.docker.com/
+# 
+# For more examples and ideas, visit:
+#  https://docs.docker.com/get-started/
+```
+
+
+## Back to the workshop
+
+[Jump !](./README.md)