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README_kubernetes_consul.md

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Running in Kubernetes (NOT WORKING)

An Kubernetes environment is required, when running locally use minikube.

Install Consul on Kubernetes

git clone https://github.com/hashicorp/consul-helm.git
cd consul-helm/ 
alias helm="docker run -ti --rm -v $(pwd):/apps -v ~/.kube:/root/.kube -v ~/.minikube:~/.minikube alpine/helm:2.11.0"
helm init
git checkout v0.4.0

Edit values.yaml so that the number of replicas is 1

helm install --name consul ./

And then according to ihttps://www.consul.io/docs/platform/k8s/dns.html we need to do

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: ConfigMap
metadata:
  labels:
    addonmanager.kubernetes.io/mode: EnsureExists
  name: kube-dns
  namespace: kube-system
data:
  stubDomains: |
    {"consul": ["$(kubectl get svc consul-dns -o jsonpath='{.spec.clusterIP}')"]}
EOF

Local build

Just make sure that everything has been built (kotlin seems to require this as the gradle run command doesn't build jars?)

./gradlew clean build

Docker builds

docker build books -t <YOUR NAMESPACE>/micronaut-books
docker build inventory -t <YOUR NAMESPACE>/micronaut-inventory
docker build gateway -t <YOUR NAMESPACE>/micronaut-gateway
docker push <YOUR NAMESPACE>/micronaut-books
docker push <YOUR NAMESPACE>/micronaut-inventory
docker push <YOUR NAMESPACE>/micronaut-gateway

Create deployments in Kubernetes

kubectl run books --image=petenorth/micronaut-books --port=8082 --env="MICRONAUT_ENVIRONMENTS=consul" --env="CONSUL_HOST=consul-server" -l=app=books
kubectl run inventory --image=petenorth/micronaut-inventory --port=8081 --env="MICRONAUT_ENVIRONMENTS=consul" --env="CONSUL_HOST=consul-server" -l=app=inventory
kubectl run gateway --image=petenorth/micronaut-gateway --port=8080 --env="MICRONAUT_ENVIRONMENTS=consul" --env="CONSUL_HOST=consul-server" -l=app=gateway

Create service definitions for the deployments

kubectl expose deployment books
kubectl expose deployment inventory
kubectl expose deployment gateway

Enable ingress using the minikube addon

minikube addons enable ingress

wait until it appears in

kubectl get pod -n kube-system -w

Scale down the deployments and then scale up to pick up the environment variables (MUST BE A BETTER WAY OF DOING THIS)

kubectl scale --replicas=0 deployment/inventory
kubectl scale --replicas=0 deployment/gateway
kubectl scale --replicas=0 deployment/books

Wait until terminated and then

kubectl scale --replicas=1 deployment/inventory
kubectl scale --replicas=1 deployment/gateway
kubectl scale --replicas=1 deployment/books

Apply ingress resource definition

kubectl apply -f kubernetes/ingress.yml

Wait until it has an address

kubectl get ing -w

Test

Access using minikube ip .

curl -L -k "http://$(minikube ip)/api/books"

Export definitions

kubectl get services --export=true -o yaml > kubernetes/services.yaml 
kubectl get deployments --export=true -o yaml > kubernetes/deployments.yaml

To recreate

The ingress definition file was created earlier and has to be created by hand as the ingress definition cannot currently be created via any simple kubectl command.

kubectl create -f kubernetes/services.yaml
kubectl create -f kubernetes/deployments.yaml
kubectl create -f kubernetes/ingress.yaml

TODO

  • Implement via Helm
  • Use Consul within Kubernetes (showing that the service discovery mechanism doesn't have to be Kubernetes based when running in Kubernetes).
  • Istio enable things (service discovery, service to service communication, metrics and logging, traffic behaviour including retries circuit breaker etc.) Means that
    • Consul not needed
    • JWT stuff not needed in application code base (??)
    • Zipkin not needed (no configuration in code base)
    • BUT think about running locally without Kubernetes/Istio
  • Enable Zipkin