Tutorial: Integrate Admin for Spring with Eureka Server for Spring in Azure Container Apps

This tutorial will guide you through the process of integrating a managed Admin for Spring with a Eureka Server for Spring within Azure Container Apps.

This article contains some content similar to the "Connect to a managed Admin for Spring in Azure Container Apps" tutorial, but with Eureka Server for Spring, you can bind Admin for Spring to Eureka Server for Spring, so that it can get application information through Eureka, instead of having to bind individual applications to Admin for Spring.

By following this guide, you'll set up a Eureka Server for service discovery and then create an Admin for Spring to manage and monitor your Spring applications registered with the Eureka Server. This setup ensures that other applications only need to bind to the Eureka Server, simplifying the management of your microservices.

In this tutorial, you will learn to:

1. Create a Eureka Server for Spring.
2. Create an Admin for Spring and link it to the Eureka Server.
3. Bind other applications to the Eureka Server for streamlined service discovery and management.

Prerequisites

To complete this tutorial, you need the following items:

Requirement	Instructions
Azure account	An active subscription is required. If you don't have one, you can create one for free.
Azure CLI	Install the Azure CLI.
An existing Eureka Server for Spring Java component	If you don't have one, follow the Create the Eureka Server for Spring section to create one.

Considerations

When running managed Java components in Azure Container Apps, be aware of the following details:

Item	Explanation
Scope	Components run in the same environment as the connected container app.
Scaling	Component can't scale. The scaling properties minReplicas and maxReplicas are both set to 1.
Resources	The container resource allocation for components is fixed. The number of the CPU cores is 0.5, and the memory size is 1Gi.
Pricing	Component billing falls under consumption-based pricing. Resources consumed by managed components are billed at the active/idle rates. You can delete components that are no longer in use to stop billing.
Binding	Container apps connect to a component via a binding. The bindings inject configurations into container app environment variables. Once a binding is established, the container app can read the configuration values from environment variables and connect to the component.

Setup

Before you begin, create the necessary resources by executing the following commands.

1. Create variables to support your application configuration. These values are provided for you for the purposes of this lesson.

   export LOCATION=chinaeast
   export RESOURCE_GROUP=my-services-resource-group
   export ENVIRONMENT=my-environment
   export EUREKA_COMPONENT_NAME=eureka
   export ADMIN_COMPONENT_NAME=admin
   export CLIENT_APP_NAME=sample-service-eureka-client
   export CLIENT_IMAGE="mcr.microsoft.com/javacomponents/samples/sample-admin-for-spring-client:latest"
   

   Variable	Description
   LOCATION	The Azure region location where you create your container app and Java components.
   RESOURCE_GROUP	The Azure resource group name for your demo application.
   ENVIRONMENT	The Azure Container Apps environment name for your demo application.
   EUREKA_COMPONENT_NAME	The name of the Eureka Server Java component.
   ADMIN_COMPONENT_NAME	The name of the Admin for Spring Java component.
   CLIENT_APP_NAME	The name of the container app that will bind to the Eureka Server.
   CLIENT_IMAGE	The container image used in your Eureka Server container app.

2. Log in to Azure with the Azure CLI.

   az cloud set -n AzureChinaCloud
   az login
   # az cloud set -n AzureCloud   //means return to Public Azure.
   

3. Create a resource group.

   az group create --name $RESOURCE_GROUP --location $LOCATION
   

4. Create your container apps environment.

   az containerapp env create \
     --name $ENVIRONMENT \
     --resource-group $RESOURCE_GROUP \
     --location $LOCATION \
     --query "properties.provisioningState"
   

   Using the --query parameter filters the response down to a simple success or failure message.

Optional: Create the Eureka Server for Spring

If you don't have an existing Eureka Server for Spring, follow the command below to create the Eureka Server Java component. For more information, see [Create the Eureka Server for Spring](java-eureka-server.md#create-the-eureka server-for-spring-java-component).

az containerapp env java-component eureka-server-for-spring create \
  --environment $ENVIRONMENT \
  --resource-group $RESOURCE_GROUP \
  --name $EUREKA_COMPONENT_NAME

Bind the components together

Create the Admin for Spring Java component.

az containerapp env java-component admin-for-spring create \
  --environment $ENVIRONMENT \
  --resource-group $RESOURCE_GROUP \
  --name $ADMIN_COMPONENT_NAME \
  --min-replicas 1 \
  --max-replicas 1 \
  --bind $EUREKA_COMPONENT_NAME

Bind other apps to the Eureka Server

With the Eureka Server set up, you can now bind other applications to it for service discovery. And you can also monitor and manage these applications in the dashboard of Admin for Spring. Follow the steps below to create and bind a container app to the Eureka Server:

Create the container app and bind it to the Eureka Server.

az containerapp create \
  --name $CLIENT_APP_NAME \
  --resource-group $RESOURCE_GROUP \
  --environment $ENVIRONMENT \
  --image $CLIENT_IMAGE \
  --min-replicas 1 \
  --max-replicas 1 \
  --ingress external \
  --target-port 8080 \
  --bind $EUREKA_COMPONENT_NAME 

View the dashboards

1. Create the custom role definition.

   az role definition create --role-definition '{
       "Name": "Java Component Dashboard Access",
       "IsCustom": true,
       "Description": "Can access managed Java Component dashboards in managed environments",
       "Actions": [
           "Microsoft.App/managedEnvironments/write"
       ],
       "AssignableScopes": ["/subscriptions/<SUBSCRIPTION_ID>"]
   }'
   

   Make sure to replace placeholder in between the <> brackets in the AssignableScopes value with your subscription ID.

2. Assign the custom role to your account on managed environment resource.

   Get the resource id of the managed environment.

   export ENVIRONMENT_ID=$(az containerapp env show \
     --name $ENVIRONMENT --resource-group $RESOURCE_GROUP \
     --query id -o tsv)
   

3. Assign the role to your account.

   Before running this command, replace the placeholder in between the <> brackets with your user or service principal ID.

   az role assignment create \
     --assignee <USER_OR_SERVICE_PRINCIPAL_ID> \
     --role "Java Component Dashboard Access" \
     --scope $ENVIRONMENT_ID
   

4. Get the URL of the Admin for Spring dashboard.

   az containerapp env java-component admin-for-spring show \
     --environment $ENVIRONMENT \
     --resource-group $RESOURCE_GROUP \
     --name $ADMIN_COMPONENT_NAME \
     --query properties.ingress.fqdn -o tsv
   

5. Get the URL of the Eureka Server for Spring dashboard.

   az containerapp env java-component eureka-server-for-spring show \
     --environment $ENVIRONMENT \
     --resource-group $RESOURCE_GROUP \
     --name $EUREKA_COMPONENT_NAME \
     --query properties.ingress.fqdn -o tsv
   

   This command returns the URL you can use to access the Eureka Server for Spring dashboard. Through the dashboard, your container app is also to you as shown in the following screenshot.

   

   

Clean up resources

The resources created in this tutorial have an effect on your Azure bill. If you aren't going to use these services long-term, run the following command to remove everything created in this tutorial.

az group delete \
    --resource-group $RESOURCE_GROUP

Next steps