Kubernetes Tutorials & Lab: Ingress with Loadbalancer

Sample Code – https://github.com/devopsschool-demo-labs-projects/kubernetes-lab-demo/tree/main/Ingress

	ssh aen@c1-cp1


	#Check out 1-ingress-nodeport.sh for the on-prem demos

	#Demo 1 - Deploying an ingress controller
	#For our Ingress Controller, we're going to go with nginx, widely available and easy to use.
	#Follow this link here to find a manifest for nginx Ingress Controller for various infrastructures, Cloud, Bare Metal, EKS and more.
	#We have to choose a platform to deploy in...we can choose Cloud, Bare-metal (which we can use in our local cluster) and more.
	https://kubernetes.github.io/ingress-nginx/deploy/


	#Cloud: Azure (Same for GCE-GKE) This Ingress Controller will be exposed as a LoadBalancer service on a real public IP.
	#Let's make sure we're in the right context and deploy the manifest for the Ingress Controller found in the link just above (around line 9).
	kubectl config use-context 'CSCluster'
	kubectl apply -f ./cloud/deploy.yaml


	#Using this manifest, the Ingress Controller is in the ingress-nginx namespace but
	#It will monitor for Ingresses in all namespaces by default. If can be scoped to monitor a specific namespace if needed.


	#Check the status of the pods to see if the ingress controller is online.
	kubectl get pods --namespace ingress-nginx


	#Now let's check to see if the service is online. This of type LoadBalancer, so do you have an EXTERNAL-IP?
	kubectl get services --namespace ingress-nginx


	#Check out the ingressclass nginx...we have not set the is-default-class so in each of our Ingresses we will need
	#specify an ingressclassname
	kubectl describe ingressclasses nginx
	#kubectl annotate ingressclasses nginx "ingressclass.kubernetes.io/is-default-class=true"


	#Demo 2 - Single Service
	#Create a deployment, scale it to 2 replicas and expose it as a serivce.
	#This service will be ClusterIP and we'll expose this service via the Ingress.
	kubectl create deployment hello-world-service-single --image=gcr.io/google-samples/hello-app:1.0
	kubectl scale deployment hello-world-service-single --replicas=2
	kubectl expose deployment hello-world-service-single --port=80 --target-port=8080 --type=ClusterIP



	#Create a single Ingress routing to the one backend service on the service port 80 listening on all hostnames
	kubectl apply -f ingress-single.yaml


	#Get the status of the ingress. It's routing for all host names on that public IP on port 80
	#This IP will be the same as the EXTERNAL-IP of the ingress controller...will take a second to update
	#If you don't define an ingressclassname and don't have a default ingress class the address won't be updated.
	kubectl get ingress --watch
	kubectl get services --namespace ingress-nginx


	#Notice the backends are the Service's Endpoints...so the traffic is going straight from the Ingress Controller to the Pod cutting out the kube-proxy hop.
	#Also notice, the default backend is the same service, that's because we didn't define any rules and
	#we just populated ingress.spec.backend. We're going to look at rules next...
	kubectl describe ingress ingress-single


	#Access the application via the exposed ingress on the public IP
	INGRESSIP=$(kubectl get ingress -o jsonpath='{ .items[].status.loadBalancer.ingress[].ip }')
	curl http://$INGRESSIP






	#Demo 3 - Multiple Services with path based routing
	#Let's create two additional services
	kubectl create deployment hello-world-service-blue --image=gcr.io/google-samples/hello-app:1.0
	kubectl create deployment hello-world-service-red --image=gcr.io/google-samples/hello-app:1.0

	kubectl expose deployment hello-world-service-blue --port=4343 --target-port=8080 --type=ClusterIP
	kubectl expose deployment hello-world-service-red --port=4242 --target-port=8080 --type=ClusterIP


	#Let's create an ingress with paths each routing to different backend services.
	kubectl apply -f ingress-path.yaml


	#We now have two, one for all hosts and the other for our defined host with two paths
	#The Ingress controller is implementing these ingresses and we're sharing the one public IP, don't proceed until you see
	#the address populated for your ingress
	kubectl get ingress --watch


	#We can see the host, the path, and the backends.
	kubectl describe ingress ingress-path


	#Our ingress on all hosts is still routing to service single, since we're accessing the URL with an IP and not a domain name or host header.
	curl http://$INGRESSIP/


	#Our paths are routing to their correct services, if we specify a host header or use a DNS name to access the ingress. That's how the rule will route the request.
	curl http://$INGRESSIP/red --header 'Host: path.example.com'
	curl http://$INGRESSIP/blue --header 'Host: path.example.com'


	#Example prefix matches...these will all match and get routed to red
	curl http://$INGRESSNODEPORTIP:$NODEPORT/red/1 --header 'Host: path.example.com'
	curl http://$INGRESSNODEPORTIP:$NODEPORT/red/2 --header 'Host: path.example.com'


	#Example Exact mismatches...these will all 404
	curl http://$INGRESSNODEPORTIP:$NODEPORT/Blue --header 'Host: path.example.com'
	curl http://$INGRESSNODEPORTIP:$NODEPORT/blue/1 --header 'Host: path.example.com'
	curl http://$INGRESSNODEPORTIP:$NODEPORT/blue/2 --header 'Host: path.example.com'


	#If we don't specify a path we'll get a 404 while specifying a host header.
	#We'll need to configure a path and backend for / or define a default backend for the service
	curl http://$INGRESSIP/ --header 'Host: path.example.com'


	#Let's add a backend to the ingress listenting on path.example.com pointing to the single service
	kubectl apply -f ingress-path-backend.yaml


	#We can see the default backend, and in the Rules, the host, the path, and the backends.
	kubectl describe ingress ingress-path


	#Now we'll hit the default backend service, single
	curl http://$INGRESSIP/ --header 'Host: path.example.com'




	#Demo 4 - Name based virtual hosts
	#Now, let's route traffic to the services using named based virtual hosts rather than paths, wait for ADDRESS to be populated
	kubectl apply -f ingress-namebased.yaml
	kubectl get ingress --watch

	curl http://$INGRESSIP/ --header 'Host: red.example.com'
	curl http://$INGRESSIP/ --header 'Host: blue.example.com'




	#TLS Example
	#1 - Generate a certificate
	openssl req -x509 -nodes -days 365 -newkey rsa:2048 \
	-keyout tls.key -out tls.crt -subj "/C=US/ST=ILLINOIS/L=CHICAGO/O=IT/OU=IT/CN=tls.example.com"


	#2 - Create a secret with the key and the certificate
	kubectl create secret tls tls-secret --key tls.key --cert tls.crt


	#3 - Create an ingress using the certificate and key. This uses HTTPS for both / and /red
	kubectl apply -f ingress-tls.yaml


	#Check the status...do we have an IP?
	kubectl get ingress --watch


	#Test access to the hostname...we need --resolve because we haven't registered the DNS name
	#TLS is a layer lower than host headers, so we have to specify the correct DNS name.
	curl https://tls.example.com:443 --resolve tls.example.com:443:$INGRESSIP --insecure --verbose







	#Clean up from our demo
	kubectl delete ingresses ingress-path
	kubectl delete ingresses ingress-tls
	kubectl delete ingresses ingress-namebased
	kubectl delete deployment hello-world-service-single
	kubectl delete deployment hello-world-service-red
	kubectl delete deployment hello-world-service-blue
	kubectl delete service hello-world-service-single
	kubectl delete service hello-world-service-red
	kubectl delete service hello-world-service-blue
	kubectl delete secret tls-secret
	rm tls.crt
	rm tls.key

	#Delete the ingress, ingress controller and other configuration elements
	kubectl delete -f ./cloud/deploy.yaml

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