Configuring a Java microservices

• Objective - Breakout rooms to configuring a java microservices:
  • have a driver
  • Documenter
  • All must complete the tutorial
  • presenter

Overview

• Prerequisites
• Start Kubernetes
• Navigate to microservices directory
• Build each microservice
• Deploy each microservice
• Check Status of Microservices
• Send GET Request to system Service
• Send GET Request to inventory Service
• Fetch Current Values from Kubernetes ConfigMap
• Modify Values from Kubernetes ConfigMap
• Modify System Microservice
• Modify Inventory Microservice
• Create ConfigMap
• Create Secret to Configgure Inventory Service Credentials
• Update Kubernetes Resources
• Add Kubernetes.yml to start directory
• Deploy Changes
• Delete Old Kubernetes Deployment
• Check Staus of Pods of Services
• Call Updated System Service
• Verify Inventory Service is using Kubernetes Secret

Prerequisites

• Install Docker
• Install Kubectl
• Install Minikube

Clone Project

• Clone project by clicking here

Start Kubernetes

Navigate to microservices directory

• Execute the command below to navigate to microservices directory
  • cd guide-kubernetes-microprofile-config/start/

Build Each Microservice

• Build each microservice
  • mvn package -pl system
  • mvn package -pl inventory

Deploy Each microservice

• Use the yaml file to deploy 2 microservices and accompanying services by executing command below
  • kubectl apply -f kubernetes.yaml

Check Status of Microservices

• The two commands below will check the status of the pods and check when they are in a ready state.
• This is done by providing the command with the labels for the pod such as inventory.
• Issue the following commands to check the status of your microservices:

kubectl wait --for=condition=ready pod -l app=inventory
kubectl wait --for=condition=ready pod -l app=system

Send GET Request to system Service

• use curl to make an HTTP GET request to the system service.
• The service is secured with a user id and password that is passed in the request.
• Execute the command below
  • curl -u bob:bobpwd http://$( minikube ip ):31000/system/properties

Send GET Request to inventory Service

• The inventory service will call the system service and store the response data in the inventory service before returning the result.
• use the following curl command to call the inventory service:
• Execute the command below
  • curl http://$( minikube ip ):32000/inventory/systems/system-service

Fetch Current Values from Kubernetes ConfigMap

• use a Kubernetes ConfigMap to modify the X-App-Name: response header.
• Take a look at their current values by running the following curl command:

curl -# -I -u bob:bobpwd -D - http://$( minikube ip ):31000/system/properties | grep -i ^X-App-Name:

Modify Values from Kubernetes ConfigMap

• use a Kubernetes ConfigMap to modify the X-App-Name: response header.
• Take a look at their current values by running the following curl command:

curl -# -I -u bob:bobpwd -D - http://$( minikube ip ):31000/system/properties | grep -i ^X-App-Name:

Modify System Microservice

• The system service is hardcoded to have system as the app name.
• To make this configurable, add the appName member and code to set the X-App-Name to the SystemResource file.
• Add the code below to the file /guide-kubernetes-microprofile-config/start/system/src/main/java/system/SystemResource.java
• These changes use MicroProfile Config and CDI to inject the value of an environment variable called APP_NAME into the appName member of the SystemResource class.

package system;

// CDI
import javax.enterprise.context.RequestScoped;
import javax.inject.Inject;
import javax.ws.rs.GET;
// JAX-RS
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.eclipse.microprofile.config.inject.ConfigProperty;

@RequestScoped
@Path("/properties")
public class SystemResource {

  @Inject
  @ConfigProperty(name = "APP_NAME")
  private String appName;

  @Inject
  @ConfigProperty(name = "HOSTNAME")
  private String hostname;

  @GET
  @Produces(MediaType.APPLICATION_JSON)
  public Response getProperties() {
    return Response.ok(System.getProperties())
      .header("X-Pod-Name", hostname)
      .header("X-App-Name", appName)
      .build();
  }
}

Modify Inventory Microservice

• The inventory service is hardcoded to use bob and bobpwd as the credentials to authenticate against the system service.
• make these credentials configurable using a Kubernetes Secret.
• These changes use MicroProfile Config and CDI to inject the value of the environment variables SYSTEM_APP_USERNAME and SYSTEM_APP_PASSWORD into the SystemClient class.
• In a text editor, open the file by clicking on the navigating to the link below
  • /guide-kubernetes-microprofile-config/start/inventory/src/main/java/inventory/client/SystemClient.java
  • Edit the two lines under // Basic Auth Credentials with the following

  // Basic Auth Credentials
  @Inject
  @ConfigProperty(name = "SYSTEM_APP_USERNAME")
  private String username;

  @Inject
  @ConfigProperty(name = "SYSTEM_APP_PASSWORD")
  private String password;

Create ConfigMap

• Create a ConfigMap to configure the application name by executing the command below:
  • kubectl create configmap sys-app-name --from-literal name=my-system
  • This command deploys a ConfigMap named sys-app-name to your cluster.
  • It has a key called name with a value of my-system.
  • The --from-literal flag allows you to specify individual key-value pairs to store in this ConfigMap.

Create Secret to Configure Inventory Service Credentials

• Create a secret to configure the credentials that the inventory service will use to authenticate against system service with the following kubectl command:
  • kubectl create secret generic sys-app-credentials --from-literal username=bob --from-literal password=bobpwd

Update Kubernetes Resources

• Update Kubernetes deployment to set the environment variables in your containers, based on the values configured in the ConfigMap and Secret.
• Edit the kubernetes.yaml file (located in the start directory).
• This file defines the Kubernetes deployment.
  • Note the valueFrom field.
    • This specifies the value of an environment variable, and can be set from various sources.
    • Sources include
      • a ConfigMap,
      • a Secret
      • information about the cluster
    • In this example configMapKeyRef sets the key name with the value of the ConfigMap sys-app-name. Similarly, secretKeyRef sets the keys username and password with values from the Secret sys-app-credentials.
    • Similarly, secretKeyRef sets the keys username and password with values from the Secret sys-app-credentials.

Add Kubernetes.yml to start directory

• Edit the kubernetes.yaml file in the start directory by adding the following lines of code:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: system-deployment
  labels:
    app: system
spec:
  selector:
    matchLabels:
      app: system
  template:
    metadata:
      labels:
        app: system
    spec:
      containers:
      - name: system-container
        image: system:1.0-SNAPSHOT
        ports:
        - containerPort: 9080
        # Set the APP_NAME environment variable
        env:
        - name: APP_NAME
          valueFrom:
            configMapKeyRef:
              name: sys-app-name
              key: name
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: inventory-deployment
  labels:
    app: inventory
spec:
  selector:
    matchLabels:
      app: inventory
  template:
    metadata:
      labels:
        app: inventory
    spec:
      containers:
      - name: inventory-container
        image: inventory:1.0-SNAPSHOT
        ports:
        - containerPort: 9080
        # Set the SYSTEM_APP_USERNAME and SYSTEM_APP_PASSWORD environment variables
        env:
        - name: SYSTEM_APP_USERNAME
          valueFrom:
            secretKeyRef:
              name: sys-app-credentials
              key: username
        - name: SYSTEM_APP_PASSWORD
          valueFrom:
            secretKeyRef:
              name: sys-app-credentials
              key: password
---
apiVersion: v1
kind: Service
metadata:
  name: system-service
spec:
  type: NodePort
  selector:
    app: system
  ports:
  - protocol: TCP
    port: 9080
    targetPort: 9080
    nodePort: 31000
---
apiVersion: v1
kind: Service
metadata:
  name: inventory-service
spec:
  type: NodePort
  selector:
    app: inventory
  ports:
  - protocol: TCP
    port: 9080
    targetPort: 9080
    nodePort: 32000

Deploy Changes

• You now need rebuild and redeploy the applications for your changes to take effect.
• Rebuild the application by executing the commands below from the start directory:
  • mvn package -pl system
  • mvn package -pl inventory

Delete Old Kubernetes Deployment

• Now you need to delete your old Kubernetes deployment then deploy your updated deployment by issuing the following commands:
  • kubectl replace --force -f kubernetes.yaml

Check Staus of Pods of Services

• Check the status of the pods for the services by executing the command below:
  • kubectl get --watch pods
• You should eventually see the status of Ready for the two services.
• Press Ctrl-C to exit the terminal command.

Call Updated System Service

• Call the updated system service and check the headers by executing the command below:
  • curl -u bob:bobpwd -D - http://$( minikube ip ):31000/system/properties -o /dev/null

Verify Inventory Service is using Kubernetes Secret

• Verify that inventory service is now using the Kubernetes Secret for the credentials by executing the command below:
  • curl http://$( minikube ip ):32000/inventory/systems/system-service