Istio Sample

This sample code helps get you started with Istio Service Mesh

Related technologies:

Kotlin: https://kotlinlang.org/docs/reference/
Spring Boot: https://spring.io/projects/spring-boot#overview
Docker: https://www.docker.com/resources/what-container
Kubernetes: https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/
Minikube: https://kubernetes.io/docs/setup/learning-environment/minikube/
Istio: https://istio.io/docs/concepts/what-is-istio/
MetalLB: https://metallb.universe.tf/

What’s Here

This sample includes:

README.md - this file
pom.xml - this file is the Maven Project Object Model for the web service
demo1 - this directory contains your Kotlin Spring Boot app source files

Getting Started

To work on the sample code, you’ll need to clone project’s repository to your
local computer. If you haven’t, do that first.

Install Docker. See https://docs.docker.com/install/
Install Minikube. See https://kubernetes.io/docs/tasks/tools/install-minikube/
Install Istio. See https://istio.io/docs/setup/#downloading-the-release
Minikube comes with it’s own Docker daemon, so you don’t have to use Docker Desktop. You only need the Docker CLI and to point it to Minikube:
```
 $ eval $(minikube docker-env)
```

Create the cluster:

 $ minikube config set cpus 4 ; minikube config set memory 8192 ; minikube config set disk-size 50g ; minikube addons enable ingress ; minikube start

Into your Istio source folder, run the following command to apply the Custom Resource Definitions (CRDs):
```
 $ for i in install/kubernetes/helm/istio-init/files/crd*yaml; do kubectl apply -f $i; done
```

6.1. If you have the following error:

    error: SchemaError(io.k8s.api.networking.v1beta1.IngressList): invalid object doesn't have additional properties

6.2. Run the following command to relink kubectl:

    rm /usr/local/bin/kubectl ; brew link --overwrite kubernetes-cli

6.4. Then run again:

    $ for i in install/kubernetes/helm/istio-init/files/crd*yaml; do kubectl apply -f $i; done

Into your Istio source folder, run the following command to apply Istio in your cluster:
```
 $ kubectl apply -f install/kubernetes/istio-demo.yaml
```

7.1. To follow the Istio health in your cluster, run the following command:

    $ kubectl get pod -n istio-system

7.2. When all items from STATUS column are Completed or Running, run the following command to enable the Sidecar injection:

    $ kubectl label namespace default istio-injection=enabled

To install the Load Balancer MetalLB, run the following command:

 $ kubectl apply -f https://raw.githubusercontent.com/google/metallb/v0.7.3/manifests/metallb.yaml

8.1. To check the MetalLB health check, run the following command:

    $ kubectl get service -n istio-system istio-ingressgateway

8.2. When colunm EXTERNAL-IP has a IP address, MetalLB is running.

Run the following command to get the Minikube ip:
```
 $ minikube ip
```

9.1. Copy the result from the previous step and navigate to istio-sample (this project) folder:

    $ cd istio-sample/demo1/kube

Paste the copied IP in last section (addresses) of deployment.yaml file, example:

    # External Load Balancer
    apiVersion: v1
    kind: ConfigMap
    metadata:
      namespace: metallb-system
      name: config
    data:
      config: |
        address-pools:
        - name: custom-ip-space
          protocol: layer2
          addresses:
          - MINIKUBE IP HERE/28

Still in istio-sample folder, run the following command to deploy your Spring Boot app into your cluster:
```
$ kubectl apply -f deployment.yaml
```
Run the following command to check the Spring Boot health in your browser:
```
$ minikube dashboard
```
When all the Workloads Statuses section in Kubernetes are green, get the result of EXTERNAL-IP (step 8.1) from MetalLB and run:
```
$ curl -v YOUR-EXTERNAL-IP-HERE/welcome
```

13.1. Your Istio cluster is working \o/

To test the Canary Release, apply the following command, from your istio-sample folder:
```
$ kubectl apply -f canary.yaml
```

14.1. The traffic will be routed 80% to V1 and 20% to V2, you can test running the step 13 some times.

14.2 To rollout all the traffic to V2, run the following command:

    $ kubectl apply -f rollout_v2.yaml

14.3. The traffic will be routed 100% to V2, you can test running the step 13 some times.

For a while, That’s all Folks! :)