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Kubernetes Authentication

The authentication process in Kubernetes relies on KubernetesAuthProviders -- which are not the same as the application's auth providers. the default providers are defined in plugins/kubernetes-react/src/kubernetes-auth-provider/KubernetesAuthProviders.ts; you can add custom providers there if needed.

These providers are configured so your Kubernetes plugin can locate and access the clusters you have access to, some of them have special requirements in the third party in question, like Microsoft Entra ID (formerly Azure Active Directory) subscription or Azure RBAC support active on the cluster.

The providers currently available are summarized below:

Server Side Providers​

These providers authenticate your application with the cluster, meaning anyone that is logged in into your Backstage app will be granted the same access to Kubernetes objects, including guest users.

The server side providers are:

  • aws
  • azure
  • googleServiceAccount
  • localKubectlProxy
  • serviceAccount

AWS​

For AWS, in addition to Kubernetes configuration, you will have to set up AWS authentication. The AWS server-side authentication provider uses AWS Identity and Access Management (IAM) to authenticate to the target Account(s); you can read more about it on the page for the Integration AWS node.

Using the plugin, you can authenticate to several AWS accounts using either static AWS Access keys or short-lived Access keys generated by assuming a role, for either case you will need to install the AWS CLI utility and set it up following the steps in the linked documentation.

If you have generated static AWS security credentials, the configuration block for AWS will look like this:

aws:
  mainAccount:
  accounts:
    - accountId: '<account-number>'
      accessKeyId: ${AWS_ACCESS_KEY_ID}
      secretAccessKey: ${AWS_SECRET_ACCESS_KEY}
      region: <region>
  accountDefaults:

If your environment is set up to assume a role, the configuration would instead look like this:

aws:
  mainAccount:
    roleName: <name-of-the-role-to-assume>
    region: <region>
  accounts:
  accountDefaults:

Either of these sections needs to be present for the Kubernetes configuration to use the aws authProvider. The Kubernetes configuration looks like this:

kubernetes:
  serviceLocatorMethod:
    type: 'multiTenant'
  clusterLocatorMethods:
    - type: 'config'
      clusters:
        - url: https://<unique-identifier>.<region>.eks.amazonaws.com
          name: ${CLUSTER_NAME_TO_DISPLAY}
          authProvider: 'aws'
          caData: ${EKS_CA_DATA}
          authMetadata:
            kubernetes.io/aws-assume-role: ${ROLE_ARN_TO_ASSUME}
            kubernetes.io/aws-external-id: ${ID_FROM_AWS_ADMIN}
            kubernetes.io/x-k8s-aws-id: ${CLUSTER_NAME_IN_AWS_CONSOLE}

You get both the cluster URL and CA directly from the AWS console by going to EKS > Your cluster > Overview > Details. You will find them under 'API server endpoint' and 'Certificate authority' respectively.

If Backstage needs to assume a role when authenticating with EKS clusters, the kubernetes.io/aws-assume-role parameter can be set to the ARN of the desired role. the kubernetes.io/aws-external-id parameter in the config corresponds to the ExternalId parameter of the AssumeRole API in STS.

Azure​

The Azure provider works by authenticating on the server with the Azure CLI, please note that Microsoft Entra authentication is a requirement and has to be enabled in your AKS cluster, then follow these steps:

  • Install the Azure CLI in the environment where the backstage application will run.
  • Login with your Azure/Microsoft account with az login in the server's terminal.
  • Go to your AKS cluster's resource page in Azure Console and follow the steps in the Connect tab to set the subscription and get your credentials for kubectl integration.
  • Configure your cluster to use the azure auth provider like this:
kubernetes:
  clusterLocatorMethods:
    - type: 'config'
      clusters:
        - name: My AKS cluster
          url: ${AZURE_CLUSTER_API_SERVER_ADDRESS}
          authProvider: azure
          skipTLSVerify: true

To get the API server address for your Azure cluster, go to the Azure console page for the cluster resource, go to Overview > Properties tab > Networking section and copy paste the API server address directly in that url field.

Client Side Providers​

These providers authenticate a user with the cluster. Each Backstage user will be prompted for credentials and will have access to the clusters as long as the user has been authorized to access said cluster. If Backstage is configured to communicate with a cluster but the user isn't authorized to access it, they will see the cluster listed but will not see any resources in the plugin page for that cluster. The error will show as 401 or similar.

The providers available as client side are:

  • aks
  • google
  • oidc