hosting

many online solutions are available for hosting your web apps

• static hosting

  • surge.sh

  • netlify.com

  • vercel.com

• CI/CD

  • github pages (powered by github actions)

  • readthedocs.io

  • ...

Fast and easy: fly.io¶

It’s rather easy to host you web app on fly.io; the repo below shows how to do it using Continuous Deployment (CD) with Github Actions on a super-simple FastAPI app.

https://github.com/ue22-p25/backend-fastapi-flyio

there are many advantages with this kind of service:

• you can deploy your app in a few minutes

• you pay as you use it

• and the machines get turned off automatically when not in use

• you can scale up and down easily

Cloud operators¶

Many operators offer cloud services

• AWS

• Google Cloud

• Azure

• Digital Ocean

• Scaleway

• OVH

• etc..

Cloud offerings¶

• metal

  • bare metal servers

• instances

  • virtual machines

• kubernetes

  • the substrate is ready for you

  • kube is about container orchestration

  • this means you just write yaml files

  • you describe the state you want to reach

  • not the order in which to do things

  • the kube engine will take care of it

  • offers a huge number of sophisticated features

  • e.g. load balancing, replicas, scaling, ...

k8s has a rather steep learning curve, but very much worth it;
particularly as it is a standard and you can use it on any cloud provider

Illustration on Scaleway¶

• web console

• docs & the API

• the CLI

• billing

• monitoring

  • prometheus

  • grafana

  • graphQL

Docker: a container engine¶

• what is a container ? think of it as:

  • a root image (filesystem)

  • a set of processes (process group)

  • a network namespace (IP address)

• in short, it is a lightwight virtual machine

  • except that it shares the kernel with the host OS

• an app vendor can package their app

  • with all its dependencies

  • and ship it as a container image

• so in pratical terms:

  • instead of running a service inside an OS, you run it inside a container

  • e.g. you can run a linux-based nginx server inside a container in a Windows machine

  • note there are some gory tricks at work (does WSL rings a bell ?)

CI/CD¶

Continuous Integration / Continuous Deployment¶

• CI/CD is a set of practices that enable development teams to deliver code changes more frequently and reliably

• CI focuses on automating the integration of code changes from multiple contributors into a single software project

• CD automates the deployment of code changes to production

• example : github actions

  • look at the .github/workflows folder

• example: readthedocs (continuous documentation)

  • in the numerique course, see the .readthedocs.yaml file

firewalls¶

• a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules

• typically it is configured to allow or deny traffic based on

  • IP addresses

  • ports

  • and protocols

• typically if you set up a web server in the cloud, you will

  • deny all traffic

  • except TCP incoming traffic on port 22 (SSH)

  • and on port 80 (HTTP) and/or port 443 (HTTPS)

any temporary need (join a debug endpoint on port 9000, for example) can be done through a SSH tunnel