Invoke one Microservices from another - PART 2: Kubernetes
In this guide, you will learn HOW-TO run the Docker Images you built in Invoke one Microservices from another - PART 1: Container Images on Kubernetes.
Prerequisites
To complete this guide, you need:
Introduction
In this guide, we will deploy on Kubernetes the two container images we created in Invoke one Microservices from another - PART 1: Container Images;
Minikube
You can use whatever Kubernetes cluster you have available; in this guide, and in the following, we will use minikube.
Microservice B - the server
Image Registry
To make the simple-microservice-server:latest Docker Image available to Kubernetes, you need to push it to some Image Registry that is accessible by the Kubernetes cluster you want to use.
Quay.io
There are many Image Registries you can use: in this guide, we will push the simple-microservice-server:latest Docker Image, to the quay.io Image Registry.
Create a public repository named simple-microservice-server on quay.io (e.g. https://quay.io/repository/tborgato/simple-microservice-server).
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Note
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replace tborgato with the name of your account in all the commands that will follow
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Tag the Docker image:
podman tag simple-microservice-server quay.io/tborgato/simple-microservice-serverPush the simple-microservice-server Docker Image to it:
podman push quay.io/tborgato/simple-microservice-serverAt this point, the simple-microservice-server:latest Docker Image should be publicly available and free to be consumed by any Kubernetes Cluster;
Deploy on Kubernetes
Create a folder named kubernetes in the root of your project and create a file named simple-microservice-server-deployment.yaml inside it:
apiVersion: apps/v1
kind: Deployment
metadata:
name: simple-microservice-server-deployment
labels:
app: simple-microservice-server
spec:
replicas: 1
selector:
matchLabels:
app: simple-microservice-server
template:
metadata:
labels:
app: simple-microservice-server
spec:
containers:
- name: simple-microservice-server
image: quay.io/tborgato/simple-microservice-server
ports:
- containerPort: 8080
- containerPort: 9990
livenessProbe:
httpGet:
path: /health/live
port: 9990
readinessProbe:
httpGet:
path: /health/ready
port: 9990
startupProbe:
httpGet:
path: /health/started
port: 9990Deploy to your Kubernetes Cluster:
kubectl apply -f kubernetes/simple-microservice-server-deployment.yaml|
Note
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before running any kubectl remember to start you Kubernetes cluster (use minikube start if using minikube)
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Create Kubernetes ClusterIP Service
We create a kubernetes service to consume the services exposed by simple-microservice-server from inside Kubernetes;
Create a file named simple-microservice-server-service.yaml in the kubernetes folder:
apiVersion: v1
kind: Service
metadata:
name: simple-microservice-server-service
labels:
app: simple-microservice-server
spec:
ports:
- name: http
protocol: TCP
port: 8080
targetPort: 8080
selector:
app: simple-microservice-server
type: ClusterIPDeploy to your Kubernetes Cluster:
kubectl apply -f kubernetes/simple-microservice-server-service.yamlCheck Kubernetes Service
kubectl run --rm -it --tty curl-simple-microservice-server --image=curlimages/curl --restart=Never -- http://simple-microservice-server-service:8080/hello/pippoMicroservice A - the client
Image Registry
To make the simple-microservice-client:latest Docker Image available to Kubernetes, you need to push it to some Image Registry that is accessible by the Kubernetes cluster you want to use.
Quay.io
There are many Image Registries you can use: in this guide, we will push the simple-microservice-client:latest Docker Image, to the quay.io Image Registry.
Create a public repository named simple-microservice-client on quay.io (e.g. https://quay.io/repository/tborgato/simple-microservice-client).
|
Note
|
replace tborgato with the name of your account in all the commands that will follow
|
Tag the Docker image:
podman tag simple-microservice-client quay.io/tborgato/simple-microservice-clientPush the simple-microservice-client Docker Image to it:
podman push quay.io/tborgato/simple-microservice-clientAt this point, the simple-microservice-client:latest Docker Image should be publicly available and free to be consumed by any Kubernetes Cluster;
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Note
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You can use wildfly-maven-plugin to automate the image push to an image registry
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Deploy on Kubernetes
Create a file named simple-microservice-client-deployment.yaml in the kubernetes folder:
apiVersion: apps/v1
kind: Deployment
metadata:
name: simple-microservice-client-deployment
labels:
app: simple-microservice-client
spec:
replicas: 1
selector:
matchLabels:
app: simple-microservice-client
template:
metadata:
labels:
app: simple-microservice-client
spec:
containers:
- name: simple-microservice-client
image: quay.io/tborgato/simple-microservice-client
ports:
- containerPort: 8080
- containerPort: 9990
livenessProbe:
httpGet:
path: /health/live
port: 9990
readinessProbe:
httpGet:
path: /health/ready
port: 9990
startupProbe:
httpGet:
path: /health/started
port: 9990
env:
- name: SIMPLE_MICROSERVICE_SERVER_URI
value: "http://simple-microservice-server-service:8080"|
Note
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The environment variable SIMPLE_MICROSERVICE_SERVER_URI allows simple-microservice-client to invoke simple-microservice-server through the service simple-microservice-server-service
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Deploy to your Kubernetes Cluster:
kubectl apply -f kubernetes/simple-microservice-client-deployment.yamlCreate Kubernetes NodePort Service
We create a service to consume the services exposed by simple-microservice-client from outside Kubernetes;
Create a file named simple-microservice-client-service.yaml in the kubernetes folder:
apiVersion: v1
kind: Service
metadata:
name: simple-microservice-client-service
labels:
app: simple-microservice-client
spec:
ports:
- name: http
protocol: TCP
port: 8080
targetPort: 8080
selector:
app: simple-microservice-client
type: NodePortDeploy to your Kubernetes Cluster:
kubectl apply -f kubernetes/simple-microservice-client-service.yamlCheck your application
Find out on what IP address/port, minikube is exposing your service:
$ minikube service simple-microservice-client-service --url
http://192.168.39.143:30347Verify it’s working as expected:
$ curl http://192.168.39.143:30347/hello/pippo
Hello 'pippo'.References
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Source code for this guide:
