Azure App Configuration Kubernetes Provider reference

The following reference outlines the properties supported by the Azure App Configuration Kubernetes Provider v1.3.0. See release notes for more information on the change.

Properties

An AzureAppConfigurationProvider resource has the following top-level child properties under the spec. Either endpoint or connectionStringReference has to be specified.

The spec.target property has the following child property.

If the spec.target.configMapData property is not set, the generated ConfigMap is populated with the list of key-values retrieved from Azure App Configuration, which allows the ConfigMap to be consumed as environment variables. Update this property if you wish to consume the ConfigMap as a mounted file. This property has the following child properties.

The spec.auth property isn't required if the connection string of your App Configuration store is provided by setting the spec.connectionStringReference property. Otherwise, one of the identities, service principal, workload identity, or managed identity, is used for authentication. The spec.auth has the following child properties. Only one of them should be specified. If none of them are set, the system-assigned managed identity of the virtual machine scale set is used.

The spec.auth.workloadIdentity property has the following child properties. One of them must be specified.

The spec.auth.workloadIdentity.managedIdentityClientIdReference property has the following child properties.

The spec.configuration has the following child properties.

If the spec.configuration.selectors property isn't set, all key-values with no label are downloaded. It contains an array of selector objects, which have the following child properties. Note that the key-values of the last selector take precedence and override any overlapping keys from the previous selectors.

The spec.configuration.refresh property has the following child properties.

The spec.configuration.refresh.monitoring.keyValues is an array of objects, which have the following child properties.

The spec.secret property has the following child properties. It is required if any Key Vault references are expected to be downloaded. To learn more about the support for Kubernetes built-in types of Secrets, see Types of Secret.

The spec.secret.target property has the following child property.

If the spec.secret.auth property isn't set, the system-assigned managed identity is used. It has the following child properties.

The authentication method of each Key Vault can be specified with the following properties. One of managedIdentityClientId, servicePrincipalReference or workloadIdentity must be provided.

The spec.secret.refresh property has the following child properties.

The spec.featureFlag property has the following child properties. It is required if any feature flags are expected to be downloaded.

If the spec.featureFlag.selectors property isn't set, feature flags are not downloaded. It contains an array of selector objects, which have the following child properties. Note that the feature flags of the last selector take precedence and override any overlapping keys from the previous selectors.

The spec.featureFlag.refresh property has the following child properties.

Installation

Use the following helm install command to install the Azure App Configuration Kubernetes Provider. See helm-values.yaml for the complete list of parameters and their default values. You can override the default values by passing the --set flag to the command.

helm install azureappconfiguration.kubernetesprovider \
    oci://mcr.microsoft.com/azure-app-configuration/helmchart/kubernetes-provider \
    --namespace azappconfig-system \
    --create-namespace

Autoscaling

By default, autoscaling is disabled. However, if you have multiple AzureAppConfigurationProvider resources to produce multiple ConfigMaps/Secrets, you can enable horizontal pod autoscaling by setting autoscaling.enabled to true.

Examples

Authentication

Use system-assigned managed identity of virtual machine scale set

1. Enable the system-assigned managed identity in the virtual machine scale set used by the Azure Kubernetes Service (AKS) cluster.

2. Grant the system-assigned managed identity App Configuration Data Reader role in Azure App Configuration.

3. Deploy the following sample AzureAppConfigurationProvider resource to the AKS cluster.

   apiVersion: azconfig.io/v1
   kind: AzureAppConfigurationProvider
   metadata:
     name: appconfigurationprovider-sample
   spec:
     endpoint: <your-app-configuration-store-endpoint>
     target:
       configMapName: configmap-created-by-appconfig-provider
   

Use user-assigned managed identity of virtual machine scale set

1. Create a user-assigned managed identity and note down its client ID after creation.

2. Assign the user-assigned managed identity to the virtual machine scale set used by the Azure Kubernetes Service (AKS) cluster.

3. Grant the user-assigned managed identity App Configuration Data Reader role in Azure App Configuration.

4. Set the spec.auth.managedIdentityClientId property to the client ID of the user-assigned managed identity in the following sample AzureAppConfigurationProvider resource and deploy it to the AKS cluster.

   apiVersion: azconfig.io/v1
   kind: AzureAppConfigurationProvider
   metadata:
     name: appconfigurationprovider-sample
   spec:
     endpoint: <your-app-configuration-store-endpoint>
     target:
       configMapName: configmap-created-by-appconfig-provider
     auth:
       managedIdentityClientId: <your-managed-identity-client-id>
   

Use service principal

1. Create a Service Principal

2. Grant the service principal App Configuration Data Reader role in Azure App Configuration.

3. Create a Kubernetes Secret in the same namespace as the AzureAppConfigurationProvider resource and add azure_client_id, azure_client_secret, and azure_tenant_id of the service principal to the Secret.

4. Set the spec.auth.servicePrincipalReference property to the name of the Secret in the following sample AzureAppConfigurationProvider resource and deploy it to the Kubernetes cluster.

   apiVersion: azconfig.io/v1
   kind: AzureAppConfigurationProvider
   metadata:
     name: appconfigurationprovider-sample
   spec:
     endpoint: <your-app-configuration-store-endpoint>
     target:
       configMapName: configmap-created-by-appconfig-provider
     auth:
       servicePrincipalReference: <your-service-principal-secret-name>
   

Use workload identity

1. Enable Workload Identity on the Azure Kubernetes Service (AKS) cluster.

2. Get the OIDC issuer URL of the AKS cluster.

3. Create a user-assigned managed identity and note down its client ID after creation.

4. Create the federated identity credential between the managed identity, OIDC issuer, and subject using the Azure CLI.

   az identity federated-credential create --name "${FEDERATED_IDENTITY_CREDENTIAL_NAME}" --identity-name "${USER_ASSIGNED_IDENTITY_NAME}" --resource-group "${RESOURCE_GROUP}" --issuer "${AKS_OIDC_ISSUER}" --subject system:serviceaccount:azappconfig-system:az-appconfig-k8s-provider --audience api://AzureADTokenExchange
   

5. Grant the user-assigned managed identity App Configuration Data Reader role in Azure App Configuration.

6. Set the spec.auth.workloadIdentity.managedIdentityClientId property to the client ID of the user-assigned managed identity in the following sample AzureAppConfigurationProvider resource and deploy it to the AKS cluster.

   apiVersion: azconfig.io/v1
   kind: AzureAppConfigurationProvider
   metadata:
     name: appconfigurationprovider-sample
   spec:
     endpoint: <your-app-configuration-store-endpoint>
     target:
       configMapName: configmap-created-by-appconfig-provider
     auth:
       workloadIdentity:
         managedIdentityClientId: <your-managed-identity-client-id>
   

Use connection string

1. Create a Kubernetes Secret in the same namespace as the AzureAppConfigurationProvider resource and add Azure App Configuration connection string with key azure_app_configuration_connection_string in the Secret.

2. Set the spec.connectionStringReference property to the name of the Secret in the following sample AzureAppConfigurationProvider resource and deploy it to the Kubernetes cluster.

   apiVersion: azconfig.io/v1
   kind: AzureAppConfigurationProvider
   metadata:
     name: appconfigurationprovider-sample
   spec:
     connectionStringReference: <your-connection-string-secret-name>
     target:
       configMapName: configmap-created-by-appconfig-provider
   

Key-value selection

Use the selectors property to filter the key-values to be downloaded from Azure App Configuration.

The following sample downloads all key-values with no label.

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider

In following example, two selectors are used to retrieve two sets of key-values, each with unique labels. It's important to note that the values of the last selector take precedence and override any overlapping keys from the previous selectors.

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
  configuration:
    selectors:
      - keyFilter: app1*
        labelFilter: common
      - keyFilter: app1*
        labelFilter: development

A snapshot can be used alone or together with other key-value selectors. In the following sample, you load key-values of common configuration from a snapshot and then override some of them with key-values for development.

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
  configuration:
    selectors:
      - snapshotName: app1_common_configuration
      - keyFilter: app1*
        labelFilter: development

Key prefix trimming

The following sample uses the trimKeyPrefixes property to trim two prefixes from key names before adding them to the generated ConfigMap.

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
  configuration:
    trimKeyPrefixes: [prefix1, prefix2]

Configuration refresh

When you make changes to your data in Azure App Configuration, you might want those changes to be refreshed automatically in your Kubernetes cluster. It's common to update multiple key-values, but you don't want the cluster to pick up a change midway through the update. To maintain configuration consistency, you can use a key-value to signal the completion of your update. This key-value is known as the sentinel key. The Kubernetes provider can monitor this key-value, and the ConfigMap and Secret will only be regenerated with updated data once a change is detected in the sentinel key.

In the following sample, a key-value named app1_sentinel is polled every minute, and the configuration is refreshed whenever changes are detected in the sentinel key.

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
  configuration:
    selectors:
      - keyFilter: app1*
        labelFilter: common
    refresh:
      enabled: true
      interval: 1m
      monitoring:
        keyValues:
          - key: app1_sentinel
            label: common

Key Vault references

Authentication

In the following sample, one Key Vault is authenticated with a service principal, while all other Key Vaults are authenticated with a user-assigned managed identity.

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
  configuration:
    selectors:
      - keyFilter: app1*
  secret:
    target:
      secretName: secret-created-by-appconfig-provider
    auth:
      managedIdentityClientId: <your-user-assigned-managed-identity-client-id>
      keyVaults:
        - uri: <your-key-vault-uri>
          servicePrincipalReference: <name-of-secret-containing-service-principal-credentials>

Types of Secret

Two Kubernetes built-in types of Secrets, Opaque and TLS, are currently supported. Secrets resolved from Key Vault references are saved as the Opaque Secret type by default. If you have a Key Vault reference to a certificate and want to save it as the TLS Secret type, you can add a tag with the following name and value to the Key Vault reference in Azure App Configuration. By doing so, a Secret with the kubernetes.io/tls type will be generated and named after the key of the Key Vault reference.

Refresh of secrets from Key Vault

Refreshing secrets from Key Vaults usually requires reloading the corresponding Key Vault references from Azure App Configuration. However, with the spec.secret.refresh property, you can refresh the secrets from Key Vault independently. This is especially useful for ensuring that your workload automatically picks up any updated secrets from Key Vault during secret rotation. Note that to load the latest version of a secret, the Key Vault reference must not be a versioned secret.

The following sample refreshes all non-versioned secrets from Key Vault every hour.

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
  configuration:
    selectors:
      - keyFilter: app1*
        labelFilter: common
  secret:
    target:
      secretName: secret-created-by-appconfig-provider
    auth:
      managedIdentityClientId: <your-user-assigned-managed-identity-client-id>
    refresh:
      enabled: true
      interval: 1h

Feature Flags

In the following sample, feature flags with keys starting with app1 and labels equivalent to common are downloaded and refreshed every 10 minutes. Note that to populate feature flags in the generated ConfigMap, the configMapData.type property must be json or yaml.

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
    configMapData:
      type: json
      key: appSettings.json
  featureFlag:
    selectors:
      - keyFilter: app1*
        labelFilter: common
    refresh:
      enabled: true
      interval: 10m

ConfigMap Consumption

Applications running in Kubernetes typically consume the ConfigMap either as environment variables or as configuration files. If the configMapData.type property is absent or is set to default, the ConfigMap is populated with the itemized list of data retrieved from Azure App Configuration, which can be easily consumed as environment variables. If the configMapData.type property is set to json, yaml or properties, data retrieved from Azure App Configuration is grouped into one item with key name specified by the configMapData.key property in the generated ConfigMap, which can be consumed as a mounted file.

The following examples show how the data is populated in the generated ConfigMap with different settings of the configMapData.type property.

Assuming an App Configuration store has these key-values:

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider

data:
  key1: value1
  key2: value2
  key3: value3

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
    configMapData:
      type: json
      key: appSettings.json

data:
  appSettings.json: >-
    {"key1":"value1","key2":"value2","key3":"value3"}

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
    configMapData:
      type: yaml
      key: appSettings.yaml

data:
  appSettings.yaml: >-
    key1: value1
    key2: value2
    key3: value3

apiVersion: azconfig.io/v1
kind: AzureAppConfigurationProvider
metadata:
  name: appconfigurationprovider-sample
spec:
  endpoint: <your-app-configuration-store-endpoint>
  target:
    configMapName: configmap-created-by-appconfig-provider
    configMapData:
      type: properties
      key: app.properties

data:
  app.properties: >-
    key1=value1
    key2=value2
    key3=value3