Jhispter-Kubernetes

Demos Jhispter and Kubernetes and microservices

1) Generate all 4 projects

In a new folder, generate the JHipster microservices architecture:

• directory /uaa: User Account and Authentication (UAA) Server.
• directory /catalog: Microservice catalog.
• directory /contoso: Gateway contoso Angular 5.
• directory /number: Microservice number.

Calling yo jhipster to generate all Maven 4 projects

User Account and Authentication (UAA) Server:

Microservice catalog:

Gateway contoso:

Microservice number:

2) Adding a Product entity

In /catalog, generate a product entity:

• yo jhipster:entity product
• Add field name of type String, and marked as Required.
• Add field price of type Double, and marked as Required.
• Add field isbn of type String.

3) Test the solution

Stop all current instances:

• docker stop $(docker ps -a -q)
• docker rm $(docker ps -a -q)

Launch docker images:

• docker-compose -f uaa/src/main/docker/mysql.yml up -d
• docker-compose -f catalog/src/main/docker/jhipster-registry.yml up -d
• docker-compose -f catalog/src/main/docker/mongodb.yml up -d

Execute mvnw in each folder, in the correct order:

• uaa
• catalog
• contoso

Check those URLS:

• Check if the JHipster registry is running: http://localhost:8761.
• Check if the /catalog microservice exposes the product swagger contract: http://localhost:8081/v2/api-docs
• Check if the /contoso gateway is available : http://localhost:8080

4) Adding IsbnResource in the /number microservice

In /number/src/main/java/com/mycompany/myapp/web/rest add the following code in a java class called IsbnResource.java:

package com.mycompany.myapp.web.rest;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api")
public class IsbnResource {

    @GetMapping("/isbn")
    public String generateIsbnNumber() {
        return "ISBN-" + Math.random();
    }
}

Test those two urls to check if Swagger is available and the isbn result as well:

• http://localhost:8082/v2/api-docs
• http://localhost:8082/api/isbn : Should return an unauthorized error !

Disable the authentication for testing purpose

In /config/MicroserviceSecurityConfiguration.java, make a small modification :

• Change .antMatchers("/api/**").authenticated()
• With .antMatchers("/api/**").permitAll()
• Then test again http://localhost:8082/api/isbn: Should return a correct isbn number.

An after revert to authenticated()

5) Generate the /catalog code with the swagger generator

In /catalog directory, generate the server code using the jhispter-swagger-cli:

• yo jhipster-swagger-cli

In /client/isbn/api/ApiApiClient.java replace the code and use the @AuthorizedFeignClient annotation code :

package com.mycompany.myapp.client.isbn.api;

import com.mycompany.myapp.client.AuthorizedFeignClient;

@AuthorizedFeignClient(name="number")
public interface ApiApiClient extends ApiApi {
}

In /web/rest/ProductResource.java, replace the following code:

@Autowired
private ApiApiClient isbnClientApi;

@PostMapping("/products")
@Timed
public ResponseEntity<Product> createProduct(@Valid @RequestBody Product product) throws URISyntaxException {
    log.debug("REST request to save Product : {}", product);
    if (product.getId() != null) {
        throw new BadRequestAlertException("A new product cannot already have an ID", ENTITY_NAME, "idexists");
    }

    String isbnNumber = isbnClientApi.generateIsbnNumberUsingGET().getBody();
    product.setIsbn(isbnNumber);

    Product result = productRepository.save(product);
    return ResponseEntity.created(new URI("/api/products/" + result.getId()))
        .headers(HeaderUtil.createEntityCreationAlert(ENTITY_NAME, result.getId().toString()))
        .body(result);
}

6) Generate the kubernetes config

Create a /kubernetes folder

in the /kubernetes dir, launch the yo jhipster:kubernetes command

7) Generate the dockers images

Generate the missing Docker image(s):

./mvnw verify -Pprod dockerfile:build in \catalog
./mvnw verify -Pprod dockerfile:build in \contoso
./mvnw verify -Pprod dockerfile:build in \number
./mvnw verify -Pprod dockerfile:build in \uaa

Push images to a registry: Tag and push the images:

docker image tag catalog spertus/catalog
docker push spertus/catalog
docker image tag contoso spertus/contoso
docker push spertus/contoso
docker image tag number spertus/number
docker push spertus/number
docker image tag uaa spertus/uaa
docker push spertus/uaa

8) Create a kubernetes cluster in AZURE

Login to your Azure account and follow the instructions (you will have to copy paste a generated code):

az login

-- Check if you have valid subscription:
az account list --output table

Create a resource group named rgkub on AZURE :

az group create --name rgkub --location westeurope

Now, we are going to use the aks command line. See more informations about aks here : https://docs.microsoft.com/en-us/cli/azure/aks?view=azure-cli-latest

Then use aks to create and manage a new kubernetes cluster named jhkub:

-- Create a cluster named jhkub with 5 nodes and get the ssh keys locally
az aks create --resource-group rgkub --name jhkub --node-count 5 --generate-ssh-keys

-- Open a connection to the kubernetes cluster to be able to use kubectl command line
az aks get-credentials --resource-group rgkub --name jhkub

Usefuls command lines:

-- OPTIONAL : Set the default resource group (to omit --resource-group in command lines)
az configure --defaults group=rgkub

-- Get managed kubernetes cluster
az aks list --output table

-- Show a managed aks
az aks show --resource-group rgkub --name jhkub

-- Browse (with port forwarding) an aks dashboard
az aks browse --resource-group rgkub --name jhkub

-- Check versions available for my current cluster
az aks get-versions --resource-group rgkub --name jhkub --output table

-- Upgrade your cluster
az aks upgrade --resource-group rgkub --name jhkub --kubernetes-version 1.8.2

-- Scale node count
az aks scale --resource-group rgkub --name jhkub --node-count 10 

9) Apply kubernetes config on AZURE kubernetes cluster:

You can deploy all your apps by running:

kubectl apply -f registry
kubectl apply -f catalog
kubectl apply -f contoso
kubectl apply -f number
kubectl apply -f uaa

Use these commands to find your application's IP addresses:

kubectl get svc contoso

Useful commands to monitor your kubernetes cluster:

-- watcher on pods / svc status
kubectl get pods --watch
kubectl get svc --watch

-- Get deployment
kubectl get deployment

-- OPTIONAL : Scale on 3 replicats
kubectl scale deployment catalog --replicas 3

-- OPTIONAL : Port forwarding to see jhipster registry 
kubectl port-forward [podname] 8761:8761

10) Adding a DNS to the public ip address

If you try the application with the direct IP (something like http://52.174.25.153:8080, you will have an error during the authentication step.

If you get the logs from the Contoso pod using the command kubectl logs [podname] you will see something like:

java.lang.IllegalArgumentException: Not a valid domain name: '52.174.25.153'
        at com.google.common.base.Preconditions.checkArgument(Preconditions.java:210)
        at com.google.common.net.InternetDomainName.<init>(InternetDomainName.java:155)
        at com.google.common.net.InternetDomainName.from(InternetDomainName.java:216)
        at com.mycompany.myapp.security.oauth2.OAuth2CookieHelper.getCookieDomain(OAuth2CookieHelper.java:296)
        at com.mycompany.myapp.security.oauth2.OAuth2CookieHelper.createCookies(OAuth2CookieHelper.java:109)
        at com.mycompany.myapp.security.oauth2.OAuth2AuthenticationService.authenticate(OAuth2AuthenticationService.java:70)
        at com.mycompany.myapp.web.rest.AuthResource.authenticate(AuthResource.java:51)

To be able to resolve this issue, open the resource group generated by Azure (not rgkub for instance), and open the Public IP Address resource:

Then on the configuraition tab, add a sub domain (snowkub in my example):

Now use the fully complete address to reach your Contoso front web application:

http://snowkub.westeurope.cloudapp.azure.com:8080