lego/providers/dns/azuredns/azuredns.toml

Name = "Azure DNS"
Description = ''''''
URL = "https://azure.microsoft.com/services/dns/"
Code = "azuredns"
Since = "v4.13.0"

Example = '''
### Using client secret

AZURE_CLIENT_ID=<your service principal client ID> \
AZURE_TENANT_ID=<your service principal tenant ID> \
AZURE_CLIENT_SECRET=<your service principal client secret> \
lego --domains example.com --email your_example@email.com --dns azuredns run

### Using client certificate

AZURE_CLIENT_ID=<your service principal client ID> \
AZURE_TENANT_ID=<your service principal tenant ID> \
AZURE_CLIENT_CERTIFICATE_PATH=<your service principal certificate path> \
lego --domains example.com --email your_example@email.com --dns azuredns run

### Using Azure CLI

az login \
lego --domains example.com --email your_example@email.com --dns azuredns run

### Using Managed Identity (Azure VM)

AZURE_TENANT_ID=<your service principal tenant ID> \
AZURE_SUBSCRIPTION_ID=<your target zone subscription ID> \
AZURE_RESOURCE_GROUP=<your target zone resource group name> \
lego --domains example.com --email your_example@email.com --dns azuredns run

### Using Managed Identity (Azure Arc)

AZURE_TENANT_ID=<your service principal tenant ID> \
AZURE_SUBSCRIPTION_ID=<your target zone subscription ID> \
AZURE_RESOURCE_GROUP=<your target zone resource group name> \
IMDS_ENDPOINT=http://localhost:40342 \
IDENTITY_ENDPOINT=http://localhost:40342/metadata/identity/oauth2/token \
lego --domains example.com --email your_example@email.com --dns azuredns run

'''

Additional = '''
## Description

Azure Credentials are automatically detected in the following locations and prioritized in the following order:

1. Environment variables for client secret: `AZURE_CLIENT_ID`, `AZURE_TENANT_ID`, `AZURE_CLIENT_SECRET`
2. Environment variables for client certificate: `AZURE_CLIENT_ID`, `AZURE_TENANT_ID`, `AZURE_CLIENT_CERTIFICATE_PATH`
3. Workload identity for resources hosted in Azure environment (see below)
4. Shared credentials file (defaults to `~/.azure`), used by Azure CLI

Link:
- [Azure Authentication](https://learn.microsoft.com/en-us/azure/developer/go/azure-sdk-authentication)

### Workload identity

#### Azure Managed Identity

The Azure Managed Identity service allows linking Azure AD identities to Azure resources, without needing to manually manage client IDs and secrets.

Workloads with a Managed Identity can manage their own certificates, with permissions on specific domain names set using IAM assignments.
For this to work, the Managed Identity requires the **Reader** role on the target DNS Zone,
and the **DNS Zone Contributor** on the relevant `_acme-challenge` TXT records.

For example, to allow a Managed Identity to create a certificate for "fw01.lab.example.com", using Azure CLI:

```bash
export AZURE_SUBSCRIPTION_ID="00000000-0000-0000-0000-000000000000"
export AZURE_RESOURCE_GROUP="rg1"
export SERVICE_PRINCIPAL_ID="00000000-0000-0000-0000-000000000000"

export AZURE_DNS_ZONE="lab.example.com"
export AZ_HOSTNAME="fw01"
export AZ_RECORD_SET="_acme-challenge.${AZ_HOSTNAME}"

az role assignment create \
--assignee "${SERVICE_PRINCIPAL_ID}" \
--role "Reader" \
--scope "/subscriptions/${AZURE_SUBSCRIPTION_ID}/resourceGroups/${AZURE_RESOURCE_GROUP}/providers/Microsoft.Network/dnszones/${AZURE_DNS_ZONE}"

az role assignment create \
--assignee "${SERVICE_PRINCIPAL_ID}" \
--role "DNS Zone Contributor" \
--scope "/subscriptions/${AZURE_SUBSCRIPTION_ID}/resourceGroups/${AZURE_RESOURCE_GROUP}/providers/Microsoft.Network/dnszones/${AZURE_DNS_ZONE}/TXT/${AZ_RECORD_SET}"
```

#### Azure Managed Identity (with Azure Arc)

The Azure Arc agent provides the ability to use a Managed Identity on resources hosted outside of Azure
(such as on-prem virtual machines, or VMs in another cloud provider).

While the upstream `azidentity` SDK will try to automatically identify and use the Azure Arc metadata service,
if you get `azuredns: DefaultAzureCredential: failed to acquire a token.` error messages,
you may need to set the environment variables:
  * `IMDS_ENDPOINT=http://localhost:40342`
  * `IDENTITY_ENDPOINT=http://localhost:40342/metadata/identity/oauth2/token`

#### Workload identity for AKS

Workload identity allows workloads running Azure Kubernetes Services (AKS) clusters to authenticate as an Azure AD application identity using federated credentials.

This must be configured in kubernetes workload deployment in one hand and on the Azure AD application registration in the other hand.

Here is a summary of the steps to follow to use it :
* create a `ServiceAccount` resource, add following annotations to reference the targeted Azure AD application registration : `azure.workload.identity/client-id` and `azure.workload.identity/tenant-id`.
* on the `Deployment` resource you must reference the previous `ServiceAccount` and add the following label : `azure.workload.identity/use: "true"`.
* create a fedreated credentials of type `Kubernetes accessing Azure resources`, add the cluster issuer URL  and add the namespace and name of your kubernetes service account.

Link :
- [Azure AD Workload identity](https://azure.github.io/azure-workload-identity/docs/topics/service-account-labels-and-annotations.html)

'''

[Configuration]
  [Configuration.Credentials]
    AZURE_CLIENT_ID = "Client ID"
    AZURE_CLIENT_SECRET = "Client secret"
    AZURE_TENANT_ID = "Tenant ID"
    AZURE_SUBSCRIPTION_ID = "DNS zone subscription ID"
    AZURE_RESOURCE_GROUP = "DNS zone resource group"
  [Configuration.Additional]
    AZURE_ENVIRONMENT = "Azure environment, one of: public, usgovernment, and china"
    AZURE_PRIVATE_ZONE = "Set to true to use Azure Private DNS Zones and not public"
    AZURE_ZONE_NAME = "Zone name to use inside Azure DNS service to add the TXT record in"
    AZURE_TTL = "The TTL of the TXT record used for the DNS challenge"
    AZURE_POLLING_INTERVAL = "Time between DNS propagation check"
    AZURE_PROPAGATION_TIMEOUT = "Maximum waiting time for DNS propagation"

[Links]
  API = "https://docs.microsoft.com/en-us/go/azure/"
  GoClient = "https://github.com/Azure/azure-sdk-for-go"