Azure DNS
Configuration for Azure DNS.
- Code:
azuredns
- Since: v4.13.0
Here is an example bash command using the Azure DNS provider:
### 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_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> \
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
Credentials
Environment Variable Name | Description |
---|---|
AZURE_CLIENT_CERTIFICATE_PATH |
Client certificate path |
AZURE_CLIENT_ID |
Client ID |
AZURE_CLIENT_SECRET |
Client secret |
AZURE_TENANT_ID |
Tenant ID |
The environment variable names can be suffixed by _FILE
to reference a file instead of a value.
More information here.
Additional Configuration
Environment Variable Name | Description |
---|---|
AZURE_AUTH_METHOD |
Specify which authentication method to use |
AZURE_AUTH_MSI_TIMEOUT |
Managed Identity timeout duration |
AZURE_ENVIRONMENT |
Azure environment, one of: public, usgovernment, and china |
AZURE_POLLING_INTERVAL |
Time between DNS propagation check |
AZURE_PRIVATE_ZONE |
Set to true to use Azure Private DNS Zones and not public |
AZURE_PROPAGATION_TIMEOUT |
Maximum waiting time for DNS propagation |
AZURE_RESOURCE_GROUP |
DNS zone resource group |
AZURE_SERVICEDISCOVERY_FILTER |
Advanced ServiceDiscovery filter using Kusto query condition |
AZURE_SUBSCRIPTION_ID |
DNS zone subscription ID |
AZURE_TTL |
The TTL of the TXT record used for the DNS challenge |
AZURE_ZONE_NAME |
Zone name to use inside Azure DNS service to add the TXT record in |
The environment variable names can be suffixed by _FILE
to reference a file instead of a value.
More information here.
Description
Several authentication methods can be used to authenticate against Azure DNS API.
Default Azure Credentials (default option)
Default Azure Credentials automatically detects in the following locations and prioritized in the following order:
- Environment variables for client secret:
AZURE_CLIENT_ID
,AZURE_TENANT_ID
,AZURE_CLIENT_SECRET
- Environment variables for client certificate:
AZURE_CLIENT_ID
,AZURE_TENANT_ID
,AZURE_CLIENT_CERTIFICATE_PATH
- Workload identity for resources hosted in Azure environment (see below)
- Shared credentials (defaults to
~/.azure
folder), used by Azure CLI
Link:
Environment variables
Service Discovery
Lego automatically finds all visible Azure (private) DNS zones using Azure ResourceGraph query.
This can be limited by specifying environment variable AZURE_SUBSCRIPTION_ID
and/or AZURE_RESOURCE_GROUP
which limits the
DNS zones to only a subscription or to one resourceGroup.
Additionally environment variable AZURE_SERVICEDISCOVERY_FILTER
can be used to filter DNS zones with an addition Kusto filter eg:
resources
| where type =~ "microsoft.network/dnszones"
| ${AZURE_SERVICEDISCOVERY_FILTER}
| project subscriptionId, resourceGroup, name
Client secret
The Azure Credentials can be configured using the following environment variables:
- AZURE_CLIENT_ID = “Client ID”
- AZURE_CLIENT_SECRET = “Client secret”
- AZURE_TENANT_ID = “Tenant ID”
This authentication method can be specifically used by setting the AZURE_AUTH_METHOD
environment variable to env
.
Client certificate
The Azure Credentials can be configured using the following environment variables:
- AZURE_CLIENT_ID = “Client ID”
- AZURE_CLIENT_CERTIFICATE_PATH = “Client certificate path”
- AZURE_TENANT_ID = “Tenant ID”
This authentication method can be specifically used by setting the AZURE_AUTH_METHOD
environment variable to env
.
Workload identity
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
andazure.workload.identity/tenant-id
. - on the
Deployment
resource you must reference the previousServiceAccount
and add the following label :azure.workload.identity/use: "true"
. - create a federated credentials of type
Kubernetes accessing Azure resources
, add the cluster issuer URL and add the namespace and name of your kubernetes service account.
Link :
This authentication method can be specifically used by setting the AZURE_AUTH_METHOD
environment variable to wli
.
Azure Managed Identity
Azure Managed Identity (with Azure workload)
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:
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}"
A timeout wrapper is configured for this authentication method.
The duration can be configured by setting the AZURE_AUTH_MSI_TIMEOUT
.
The default timeout is 2 seconds.
This authentication method can be specifically used by setting the AZURE_AUTH_METHOD
environment variable to msi
.
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
A timeout wrapper is configured for this authentication method.
The duration can be configured by setting the AZURE_AUTH_MSI_TIMEOUT
.
The default timeout is 2 seconds.
This authentication method can be specifically used by setting the AZURE_AUTH_METHOD
environment variable to msi
.
Azure CLI
The Azure CLI is a command-line tool provided by Microsoft to interact with Azure resources.
It provides an easy way to authenticate by simply running az login
command.
The generated token will be cached by default in the ~/.azure
folder.
This authentication method can be specifically used by setting the AZURE_AUTH_METHOD
environment variable to cli
.
Open ID Connect
Open ID Connect is a mechanism that establish a trust relationship between a running environment and the Azure AD identity provider.
It can be enabled by setting the AZURE_AUTH_METHOD
environment variable to oidc
.