Configuring OpenID Connect for Azure

This document outlines the steps required to configure Pulumi to use OpenID Connect to authenticate with Azure. OIDC in Azure uses workload identity federation to access Azure resources via a Microsoft Entra App. Access to the temporary credentials is authorized using federated credentials that validate the contents of the OIDC token issued by the Pulumi Cloud.

Prerequisites

• You must have access in the Azure Portal to create and configure Microsoft Entra App registrations.

Create a Microsoft Entra application

In the navigation pane of the Microsoft Entra console:

1. Select App registrations and then click New registration.
2. Provide a name for your application (ex: pulumi-esc-oidc-app).
3. In the Supported account types section, select Accounts in this organizational directory only.
4. Click Register.

After the Microsoft Entra application has been created, take note of the following details:

• Subscription ID
• Application (client) ID
• Directory (tenant) ID

These values will be necessary when enabling OIDC for your service.

Add federated credentials

Once you have created your new application registration, you will be redirected to the application’s Overview page. In the left navigation menu:

1. Navigate to the Certificates & secrets pane.
2. Select the Federated credentials tab.
3. Click on the Add credential button. This will start the “Add a credential” wizard.
4. In the wizard, select Other Issuer as the Federated credential scenario.
5. Fill in the remaining form fields as follows:
   • Issuer: https://api.pulumi.com/oidc
   • Subject Identifier: must be a valid subject claim (see examples at the end of this section).
   • Name: An arbitrary name for the credential, e.g. “pulumi-oidc-credentials”
   • Audience: This is different between Pulumi deployments and ESC. For Deployments this is only the name of your Pulumi organization. For ESC this is the name of your Pulumi organization prefixed with azure: (e.g. azure:{org}).
     For environments in the default project the audience will use just the Pulumi organization name. This is to prevent regressions for legacy environments.

Create a service principal

To provide Pulumi services the ability to deploy, manage, and interact with Azure resources, you need to associate your Microsoft Entra application with your Subscription or Resource Group.

1. Navigate to the Subscriptions page of the Azure portal.
2. Select the subscription to create the service principal in.
   • If you want to limit access to a specific resource group, go to the Resource Groups page instead and select the desired resource group.
3. In the left navigation menu, select Access control (IAM).
4. Click Add > Add role assignment to be taken to the Add role assignment wizard.
5. Under the Job function roles tab, select the desired role from the list, then click Next.
6. Select User, group, or service principal, then click Select members
7. Enter the name of the application you created in a previous step, select it from the list, then click Select.
8. Click Next and then Review + assign.

Configure ESC for OIDC

To configure OIDC for Pulumi ESC, create a new environment in the Pulumi Console. Make sure that you have the correct organization selected in the left-hand navigation menu. Then:

1. Click the Environments link.

2. Click the Create environment button.

3. Provide a project to create your new environment in and a name for your environment.

   • This should be the same as the identifier provided in the subject claim of your federated credentials.

4. Click the Create environment button.

5. You will be presented with a split-pane view. Delete the default placeholder content in the editor and replace it with the following code:

   values:
     azure:
       login:
         fn::open::azure-login:
           clientId: <your-client-id>
           tenantId: <your-tenant-id>
           subscriptionId: /subscriptions/<your-subscription-id>
           oidc: true
     environmentVariables:
       ARM_USE_OIDC: 'true'
       ARM_CLIENT_ID: ${azure.login.clientId}
       ARM_TENANT_ID: ${azure.login.tenantId}
       ARM_OIDC_TOKEN: ${azure.login.oidc.token}
       ARM_SUBSCRIPTION_ID: ${azure.login.subscriptionId}
   

6. Replace <your-client-id>, <your-tenant-id>, and <your-subscription-id> with the values from the previous steps.

7. Scroll to the bottom of the page and click Save.

You can validate that your configuration is working by running either of the following:

• esc open <your-org>/<your-project>/<your-environment> command of the ESC CLI
• pulumi env open <your-org>/<your-project>/<your-environment> command of the Pulumi CLI

Make sure to replace <your-org>, <your-project>, and <your-environment> with the values of your Pulumi organization, project, and environment file respectively. You should see output similar to the following:

{
  "azure": {
    "login": {
      "clientId": "b537....",
      "oidc": {
        "token": "eyJh...."
      },
      "subscriptionId": "0282....",
      "tenantId": "7061...."
    }
  },
  "environmentVariables": {
    "ARM_CLIENT_ID": "b537....",
    "ARM_OIDC_TOKEN": "eyJh....",
    "ARM_SUBSCRIPTION_ID": "0282....",
    "ARM_TENANT_ID": "7061....",
    "ARM_USE_OIDC": "true"
  }
}

To learn more about how to set up and use the various providers in Pulumi ESC, please refer to the relevant Pulumi documentation

Subject claim customization

You can customize the subject claim in the OIDC token to control which Pulumi environments or users are allowed to assume a given IAM role. This allows for more granular access control than the default organization-level permissions

This is done by configuring the subjectAttributes setting. It expects an array of keys to include in it:

• rootEnvironment.name: the name of the environment that is opened first. This root environment in turn opens other imported environments
• currentEnvironment.name: the full name (including the project) of the environment where the ESC login provider and subjectAttributes are defined
• pulumi.user.login: the login identifier of the user opening the environment
• pulumi.organization.login: the login identifier of the organization

The subject always contains the following prefix pulumi:environments:pulumi.organization.login:{ORGANIZATION_NAME} and every key configured will be appended to this prefix. For example, consider the following environment:

values:
  azure:
    login:
      fn::open::azure-login:
        ...
        subjectAttributes:
          - currentEnvironment.name
          - pulumi.user.login

The subject will be pulumi:environments:pulumi.organization.login:contoso:currentEnvironment.name:project/development:pulumi.user.login:userLogin. Note how the keys and values are appended along with the prefix.

Subject claim example

Here is an example of a valid subject claim for the project/development environment of the contoso organization:

• pulumi:environments:org:contoso:env:project/development

The default format of the subject claim when subjectAttributes are not used is pulumi:environments:org:<organization name>:env:<project name>/<environment name>