📃 Improve Ingress exercises

slides/exercises/ingress-brief.md

@@ -2,7 +2,7 @@
 
 - Add an ingress controller to a Kubernetes cluster
 
-- Create an ingress resource for a web app on that cluster
+- Create an ingress resource for a couple of web apps on that cluster
 
 - Challenge: accessing/exposing port 80
 

slides/exercises/ingress-details.md

@@ -1,49 +1,131 @@
 # Exercise — Ingress
 
-- We want to expose a web app through an ingress controller
+- We want to expose a couple of web apps through an ingress controller
 
 - This will require:
 
-  - the web app itself (dockercoins, NGINX, whatever we want)
+  - the web apps (e.g. two instances of `jpetazzo/color`)
 
   - an ingress controller
 
-  - a domain name (`use \*.nip.io` or `\*.localdev.me`)
-
   - an ingress resource
 
 ---
 
-## Goal
+## Different scenarios
 
-- We want to be able to access the web app using a URL like:
+We will use a different deployment mechanism depending on the cluster that we have:
 
-  http://webapp.localdev.me
+- Managed cluster with working `LoadBalancer` Services
 
-  *or*
+- Local development cluster
 
-  http://webapp.A.B.C.D.nip.io
+- Cluster without `LoadBalancer` Services (e.g. deployed with `kubeadm`)
 
-  (where A.B.C.D is the IP address of one of our nodes)
+---
+
+## The apps
+
+- The web apps will be deployed similarly, regardless of the scenario
+
+- Let's start by deploying two web apps, e.g.:
+
+  a Deployment called `blue` and another called `green`, using image `jpetazzo/color`
+
+- Expose them with two `ClusterIP` Services
+
+---
+
+## Scenario "classic cloud Kubernetes"
+
+*Difficulty: easy*
+
+For this scenario, we need a cluster with working `LoadBalancer` Services.
+
+(For instance, a managed Kubernetes cluster from a cloud provider.)
+
+We suggest to use "Ingress NGINX" with its default settings.
+
+It can be installed with `kubectl apply` or with `helm`.
+
+Both methods are described in [the documentation][ingress-nginx-deploy].
+
+We want our apps to be available on e.g. http://X.X.X.X/blue and http://X.X.X.X/green
+<br/>
+(where X.X.X.X is the IP address of the `LoadBalancer` allocated by Ingress NGINX).
+
+[ingress-nginx-deploy]: https://kubernetes.github.io/ingress-nginx/deploy/
+
+---
+
+## Scenario "local development cluster"
+
+*Difficulty: easy-hard (depends on the type of cluster!)*
+
+For this scenario, we want to use a local cluster like KinD, minikube, etc.
+
+We suggest to use "Ingress NGINX" again, like for the previous scenario.
+
+Furthermore, we want to use `localdev.me`.
+
+We want our apps to be available on e.g. `blue.localdev.me` and `green.localdev.me`.
+
+The difficulty is to ensure that `localhost:80` will map to the ingress controller.
+
+(See next slide for hints!)
 
 ---
 
 ## Hints
 
-- For the ingress controller, we can use:
+- With clusters like Docker Desktop, the first `LoadBalancer` service uses `localhost`
 
-  - [ingress-nginx](https://github.com/kubernetes/ingress-nginx/blob/main/docs/deploy/index.md)
+  (if the ingress controller is the first `LoadBalancer` service, we're all set!)
 
-  - the [Traefik Helm chart](https://doc.traefik.io/traefik/getting-started/install-traefik/#use-the-helm-chart)
+- With clusters like K3D and KinD, it is possible to define extra port mappings
 
-  - the container.training [Traefik DaemonSet](https://raw.githubusercontent.com/jpetazzo/container.training/main/k8s/traefik-v2.yaml)
+  (and map e.g. `localhost:80` to port 30080 on the node; then use that as a `NodePort`)
 
-- If our cluster supports LoadBalancer Services: easy
+---
 
-  (nothing special to do)
+## Scenario "on premises cluster", take 1
 
-- For local clusters, things can be more difficult; two options:
+*Difficulty: easy*
 
-  - map localhost:80 to e.g. a NodePort service, and use `\*.localdev.me`
+For this scenario, we need a cluster with nodes that are publicly accessible.
 
-  - use hostNetwork, or ExternalIP, and use `\*.nip.io`
+We want to deploy the ingress controller so that it listens on port 80 on all nodes.
+
+This can be done e.g. with the manifests in @@LINK[k8s/traefik.yaml].
+
+We want our apps to be available on e.g. http://X.X.X.X/blue and http://X.X.X.X/green
+<br/>
+(where X.X.X.X is the IP address of any of our nodes).
+
+---
+
+## Scenario "on premises cluster", take 2
+
+*Difficulty: medium*
+
+We want to deploy the ingress controller so that it listens on port 80 on all nodes.
+
+But this time, we want to use a Helm chart to install the ingress controller.
+
+We can use either the Ingress NGINX Helm chart, or the Traefik Helm chart.
+
+Test with an untainted node first.
+
+Feel free to make it work on tainted nodes (e.g. control plane nodes) later.
+
+---
+
+## Scenario "on premises cluster", take 3
+
+*Difficulty: hard*
+
+This is similar to the previous scenario, but with two significant changes:
+
+1. We only want to run the ingress controller on nodes that have the role `ingress`.
+
+2. We don't want to use `hostNetwork`, but a list of `externalIPs` instead.