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Migrate Application Configuration Service to Config Server for Spring in Azure Container Apps

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Note

The Basic, Standard, and Enterprise plans will be deprecated starting from mid-March, 2025, with a 3 year retirement period. We recommend transitioning to Azure Container Apps. For more information, see the Azure Spring Apps retirement announcement.

The Standard consumption and dedicated plan will be deprecated starting September 30, 2024, with a complete shutdown after six months. We recommend transitioning to Azure Container Apps. For more information, see Migrate Azure Spring Apps Standard consumption and dedicated plan to Azure Container Apps.

This article applies to: ❎ Basic/Standard ✅ Enterprise

This article describes how to migrate Application Configuration Service (ACS) and Config Server to Config Server for Spring in Azure Container Apps. Azure Container Apps manages Config Server for Spring, which has similar functions as ACS or Spring Cloud Config Server in Azure Spring Apps.

Prerequisites

  • An Azure Spring Apps Enterprise plan instance with Application Configuration Service enabled.
  • An Azure Container Apps environment for Config Server and an Azure Container Apps instance.

Provision Config Server

The following steps show you how to provision a Config Server for Spring in your Azure Container Apps:

  1. Navigate to your Azure Container Apps environment in the Azure portal.

  2. In the menu, select Services > Services.

  3. Open the Configure drop-down list, and then select Java component.

  4. In the Configure Java component panel, enter the following values:

    Property Value
    Java component type Select Config Server for Spring.
    Java component name Enter configserver.

  5. In the Git repositories section, select Add, and then migrate the values from Application Configuration Service to here, as shown in the following table. Choose one repository as the default repository of Config Server for Spring.

    Property Value
    Type Select DEFAULT.
    URI Enter the value of URI of the repository.
    Branch name Enter the value of label of the repository.
    Search paths Enter the value of search path of the repository.
    Authentication Select the authentication type of the repository and enter the corresponding information.

    Leave the rest of the fields with the default values and then select Add.

  6. If you have multiple repositories, select Add to migrate other repositories. For Type, select Other, and then migrate other properties as shown in the previous step and the following table:

    Property Value
    Type Select DEFAULT.
    Pattern Enter the Patterns value for the repository in the {application} or {application}/{profile} format.

  7. In the Binding section, open the dropdown to select the apps to bind to the Config Server for Spring.

  8. Select Next.

  9. To set up Config Server, on the Review tab, select Configure, and then follow the instructions in the configuration section.

After successful creation, you can see that the Provisioning State of Config Server for Spring is Succeeded.

Resource allocation

The container resource allocation for the managed Config Server in Azure Container Apps is fixed to the following values:

  • CPU: 0.5 vCPU
  • Memory: 1 Gi

To configure the instance count of Config Server for Spring, you need to update the parameters --min-replicas and --max-replicas with the same value. This configuration ensures that the instance count remains fixed. Currently, the system doesn't support autoscaling configurations for dynamic scaling.

Configure Config Server

Select one Git repository from Application Configuration Service (ACS) as the default repository in Config Server, and other repositories as additional repositories.

The following table provides a mapping between the properties in ACS and the corresponding configurations in Config Server:

Property name in ACS CONFIGURATION_KEY CONFIGURATION_VALUE
name You don't need to map this value to Config Server.
pattern You don't need to map this value to Config Server.
uri spring.cloud.config.server.git.uri
spring.cloud.config.server.git.repos.{repoName}.uri		 The URI of the remote repository.
search path spring.cloud.config.server.git.search-paths
spring.cloud.config.server.git.repos.{repoName}.search-paths		 The search paths to use within the local working copy. By default, searches only the root.
label spring.cloud.config.server.git.default-label
spring.cloud.config.server.git.repos.{repoName}.default-label		 The label used for Git.
username spring.cloud.config.server.git.username
spring.cloud.config.server.git.repos.{repoName}.username		 The username for authentication with the remote repository if the authentication type is HTTP Basic.
password spring.cloud.config.server.git.password
spring.cloud.config.server.git.repos.{repoName}.password		 The password for authentication with the remote repository if the authentication type is HTTP Basic.
private key spring.cloud.config.server.git.private-key
spring.cloud.config.server.git.repos.{repoName}.private-key		 A valid SSH private key if the authentication type is SSH.
host key spring.cloud.config.server.git.host-key
spring.cloud.config.server.git.repos.{repoName}.host-key		 A valid SSH host key if the authentication type is SSH. Must be set if host-key-algorithm is also set.
host key algorithm spring.cloud.config.server.git.host-key-algorithm
spring.cloud.config.server.git.repos.{repoName}.host-key-algorithm		 One of ssh-dss, ssh-rsa, ssh-ed25519, ecdsa-sha2-nistp256, ecdsa-sha2-nistp384, or ecdsa-sha2-nistp521 if the authentication type is SSH. Must be set if host-key is also set.

For more Config Server properties, see the Configuration options section of Connect to a managed Config Server for Spring in Azure Container Apps.

For example, suppose you have the following configuration in ACS:

"settings": {
    "gitProperty": {
        "repositories": [
            {
                "name": "r1",
                "patterns": [
                    "application"
                ],
                "label": "master",
                "uri": "https://github.com/Azure-Samples/spring-petclinic-microservices-config"
            },
            {
                "name": "r2",
                "patterns": [
                    "customers-service"
                ],
                "label": "master",
                "uri": "https://github.com/Azure-Samples/spring-petclinic-microservices-config"
            },
            {
                "name": "r3",
                "patterns": [
                    "payment"
                ],
                "label": "main",
                "uri": "https://github.com/Azure-Samples/acme-fitness-store-config"
            }
        ]
    }
}

With this ACS configuration, you can migrate to Config Server for Spring with the following configurations:

spring.cloud.config.server.git.uri=https://github.com/Azure-Samples/spring-petclinic-microservices-config
spring.cloud.config.server.git.default-label=master
spring.cloud.config.server.git.repos.repo1.uri=https://github.com/Azure-Samples/acme-fitness-store-config
spring.cloud.config.server.git.repos.repo1.default-label=main

Change the application configuration

After you provision and configure the Config Server for Spring, use the following steps to adjust your application configuration to use it effectively:

  1. Update Spring Boot dependencies. Add the following Spring Cloud Config dependencies to your pom.xml for Maven or build.gradle for Gradle.

    <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-config</artifactId>
</dependency>

  2. Configure a profile. The profile for ACS is provided as patterns in an Azure Spring Apps deployment, while in Config Server, the profile is configured in the application's source code.

    Ensure your application uses the correct profiles - dev, prod, and so on - so that the Config Server can serve environment-specific configurations.

    Update the bootstrap.yml or application.yml file in your application with the correct configuration properties to point to the Config Server, as shown in the following example:

    spring:
  cloud:
    config:
      profile: dev

  3. Configure a refresh interval. If you set a refresh interval in ACS, you can also specify the corresponding value in the spring.cloud.config.server.git.refreshRate configuration of Config Server for Spring. This value determines how frequently Config Server for Spring fetches updated configuration data from the Git backend.

    To load property changes in your application's code, using the following steps:

    1. Register a scheduled task to refresh the context in a given interval.
    2. Enable autorefresh and set the appropriate refresh interval in your application.yml file.
    3. Add @RefreshScope to your code.

    For more information, see Refresh Config Server.

Deploy the application to Azure Container Apps

After testing the application locally, you can deploy the new image to the Azure Container Apps application.

Use the following steps to deploy:

  1. Navigate to your Azure Container Apps application in the Azure portal.
  2. In the menu, select Application > Containers.
  3. Select Edit and deploy to open the Create and deploy new revision page.
  4. In the Container image section, select the image and then select Edit.
  5. In the Edit a container section, on the Properties tab, choose the new image of the application.
  6. On the Environment variables tab, for Name, specify spring.application.name. Then, for Source, choose Manual entry and specify the config file name where the application consumes the configuration.
  7. Select Save to deploy the new revision.

Troubleshoot

You can view logs for the managed Config Server for Spring in Azure Container Apps using Log Analytics. Use the following steps:

  1. Navigate to your Azure Container Apps environment in the Azure portal.

  2. Select the Monitoring > Logs menu.

  3. To view logs, enter a query into the query editor for the ContainerAppSystemLogs_CL table, as shown in the following example:

    ContainerAppSystemLogs_CL
| where ComponentType_s == "SpringCloudConfig"
| project Time=TimeGenerated, ComponentName=ComponentName_s, Message=Log_s
| take 100

For more information about querying logs, see Observability of managed Java components in Azure Container Apps.

Known limitation

Migrating ACS to Config Server for Spring only applies for Java applications. Because ACS manages configuration by using the Kubernetes-native ConfigMap. This method enables dynamic configuration updates in Kubernetes environments, making it versatile for different applications with multiple programming languages. While Spring Cloud Config Server is primarily designed for Java applications, using Spring Framework features, and thus only supports configuration management for Java.