How to programmatically assign user managed identity to Azure Data Factory - azure-data-factory

Question

I have Azure Data Factory in which I want to connect to Azure Synapse using User Assigned Managed Identity authentication type.
Three steps need to be done but unfortunately, I haven't noticed a possibility to programmatically set up step 1.
In Data Factory (Settings-> Managed Identities) assign User Managed Ideneitty
Create credentials
Create linked services
If I execute Azure ARM with only implemented second and third steps I got the following exception:
"The referenced user assigned managed identity in the credential is not associated with the factory".
Do you know how I can assign User-Managed Identity to Data Factory?

Answer 1

Had the same error messsage: "The referenced user assigned managed identity in the credential is not associated with the factory"
When doing CI/CD for arm-template I noticed that the auto generated arm-template from the datafactory only had identity type SystemAssigned. Even when when i have manually added a UserAssigned identity in the ADF GUI.
My Solution was to modify arm-template-parameters-definition.json with this.
"Microsoft.DataFactory/factories": {
"identity": "=:-identity"
}
Then in the parameter file you can pass in this :
"dataFactory_identity": {
"value": {
"type": "SystemAssigned,UserAssigned",
"userAssignedIdentities": {
"/subscriptions/<Insert_subscrptionId>/resourceGroups/<Insert_resourceGroupsName>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/<Insert_userAssignedIdentitiesName>": {}
}
}
}

Answer 2

Unfortunately, documentation for Azure Data Factory ARM is limited. I found a solution based on the documentation of the Azure Storage ARM and below it's the solution:
{
"name": "[variables('dataFactoryName')]",
"type": "Microsoft.DataFactory/factories",
"apiVersion": "2018-06-01",
"location": "[resourceGroup().location]",
"identity": {
"type": "SystemAssigned,UserAssigned",
"userAssignedIdentities": {
"[resourceId('Microsoft.ManagedIdentity/userAssignedIdentities', variables('uamiName'))]": {}
}
},