Authentication

The plugin supports four distinct authentication types, including Azure CLI integration, service principal, MSI, and raw tokens.

Azure CLI

If none of the below environment variables are set, Custodian will attempt to pull credentials and the default subscription from Azure CLI. This requires that you have run az login and selected your subscription in Azure CLI first.

Service Principal

Service principal must be provided via environment variables.

AZURE_TENANT_ID
AZURE_SUBSCRIPTION_ID
AZURE_CLIENT_ID
AZURE_CLIENT_SECRET

You can create a service principal with Azure CLI or via the Azure Portal. Created Service Principal requires Contributor role to be assigned.

Azure Portal

You can follow instructions to create and assigned required permissions to the new Service Principal: How to create Service Principal

Azure CLI

# select correct subscription
az account set -s "my subscription name"

# create service principal
az ad sp create-for-rbac --name <name> --password <password>

This will yield something like:

{
  "appId": appid,
  "displayName": name,
  "name": name,
  "password": password,
  "tenant": guid
}

You will need to map it to environment variables for Custodian like this:

AZURE_TENANT_ID=tenant
AZURE_SUBSCRIPTION_ID=subscriptionId
AZURE_CLIENT_ID=appId
AZURE_CLIENT_SECRET=password

Created Service Principal already has Contributor role.

c7n-org

If you’re using a Service Principal across subscriptions with c7n-org you’ll need to grant it access to each of the subscriptions.

Please follow this instruction to grant an access: instruction

Access Token

Passing access tokens directly is useful for integration or fake test authentication.

For fake test authentication environment variables should be configured as shown below:

AZURE_ACCESS_TOKEN=fake_token
AZURE_SUBSCRIPTION_ID=ea42f556-5106-4743-99b0-c129bfa71a47

You will also find this configuration in tox.ini.

Managed Service Identity

Learn about MSI in the Azure Documentation.

If AZURE_USE_MSI is set to any value, Custodian will attempt to use MSI.

If AZURE_CLIENT_ID is not set, Custodian will use the System Identity.

If AZURE_CLIENT_ID is set, Custodian will use the User Identity which matches the client id.

You must set AZURE_SUBSCRIPTION_ID as with the other authentication types.

AZURE_USE_MSI=1
AZURE_SUBSCRIPTION_ID=subscriptionId
AZURE_CLIENT_ID=clientId

Azure Storage access

If your service principal will be writing logs to storage or leveraging queues for mailer you should assign Storage roles, either at the subscription level or resource group/storage account level.

Please note, that you cannot leverage Azure Storage functionality if you use Access Token for authentication.

  • Blob Data Contributor
  • Queue Data Contributor

More details about Azure Storage access rights: Azure Documents