Assign ManagedID to KeyVault Access Policy - azure

I have a bicep template that creates 2 webApps and a KeyVault. Each WebApp is created with a managedID which I need to add to Keyvault so the webapp can pull in the secrets.
But when creating 2 webapps, I can't work out how to assign both ManagedIDs to KeyVault.
The bicep template is using modules
name: 'ciKeyVault'
params: {
keyVaultName: keyVaultName
aclBypass: keyVaultSettings.aclBypass
aclDefaultAction: keyVaultSettings.aclDefaultAction
enabledForDeployment: keyVaultSettings.enabledForDeployment
enabledForDiskEncryption: keyVaultSettings.enabledForDiskEncryption
enabledForTemplateDeployment: keyVaultSettings.enabledForTemplateDeployment
keyPermissions: keyVaultSettings.keyPermissions
keyVaultSettings: keyVaultSettings
secretsPermissions: keyVaultSettings.secretsPermissions
skuFamily: keyVaultSettings.skuFamily
skuName: keyVaultSettings.skuName
tenantId: subscription().tenantId
objectId: 'b71e61c4-7cff-41d0-8370-a7d9c01dde84'
}
}
and the objectId needs to be retrieved from the AppService Deployment. using this module:
module AppService '../../../Modules/Azure.App.Service.template.bicep' = [for i in range(0, length(webAppSettings.webApps)): {
name: webAppSettings.webApps[i].Name
dependsOn: [
frontEndAppServicePlan
]
params: {
webAppName: webAppSettings.webApps[i].appServiceType == 'functionApp' ? toLower('fnc-${webAppSettings.webApps[i].name}-${resourceGroupNameSuffix}') : toLower('web-${webAppSettings.webApps[i].name}-${resourceGroupNameSuffix}')
hostingPlan: frontEndAppServicePlan.outputs.hostingPlanId
virtualNetworkResourceGroup: virtualNetworkResourceGroup
environmentName:environmentName
webAppSettings:webAppSettings
appServiceType: webAppSettings.webApps[i].appServiceType
LinuxFX:webAppSettings.webApps[i].LinuxFX
appSettings:webAppSettings.webapps[i].appSettings
}
}]
Its fine when its a single appService cause I can reference the ID using output usid string = AppServices.identity.principalId
but when I have 2 appServices I can't work out how to pass in both IDs
Any ideas?
Cheers

Let's say you have a module Azure.App.Service.template.bicep that looks like that:
param webAppName string
...
// Create the web app
resource webApp 'Microsoft.Web/sites#2020-09-01' = {
name: webAppName
location: resourceGroup().location
identity: {
type: 'SystemAssigned'
}
...
}
output usid string = webApp.identity.principalId
In the parent template you can create an array of module to create your webapps (the same way you are doing it) and then create an access policies resource to grant access to key vault to all the web apps.
...
// Create the app services
module AppServices '../../../Modules/Azure.App.Service.template.bicep' = [for webApp in webAppSettings.webApps: {
name: webApp.Name
params: {
webAppName: webApp.Name
...
}
}]
// Granting the app services access ot key vault
resource appServicesKeyVaultAccessPolicies 'Microsoft.KeyVault/vaults/accessPolicies#2019-09-01' = {
name: '${keyVaultName}/add'
properties: {
accessPolicies: [for i in range(0, length(webAppSettings.webApps)): {
tenantId: subscription().tenantId
objectId: AppServices[i].outputs.usid
permissions: {
secrets: keyVaultSettings.secretsPermissions
keys: keyVaultSettings.keyPermissions
}
}]
}
}

Related

How do I configure my bicep scripts to allow a container app to pull an image from an ACR using managed identity across subscriptions

I am trialling the use of Bicep and container apps in my organisation and we have separated out concerns within the SAME tenant but in different subscriptions like so:
Development
Production
Management
I want to be able to deploy each of these subscriptions using Bicep scripts (individual ones per subscription) and ideally only use managed identity for security.
Within the management subscription we have an ACR which has the admin account intentionally disabled as I don't want to pull via username/password. Question one, should this be possible? As it seems that we should be able to configure an AcrPull role against the container app(s) without too much trouble.
The idea being that the moment the container app is deployed it pulls from the Acr and is actively useable. I don't want an intermediary such as Azure DevOps handling the orchestration for example.
In bicep I've successfully configured the workspace, container environment but upon deploying my actual app I'm a bit stuck - it fails for some incomprehensible error message which I'm still digging into. I've found plenty of examples using the admin/password approach but documentation for alternatives appears lacking which makes me worry if I'm after something that isn't feasible. Perhaps user identity is my solution?
My bicep script (whilst testing against admin/password) looks like this:
name: containerAppName
location: location
identity: {
type: 'SystemAssigned'
}
properties: {
managedEnvironmentId: containerAppEnvId
configuration: {
secrets: [
{
name: 'container-registry-password'
value: containerRegistry.listCredentials().passwords[0].value
}
]
ingress: {
external: true
targetPort: targetPort
allowInsecure: false
traffic: [
{
latestRevision: true
weight: 100
}
]
}
registries: [
{
server: '${registryName}.azurecr.io'
username: containerRegistry.listCredentials().username
passwordSecretRef: 'container-registry-password'
}
]
}
template: {
revisionSuffix: 'firstrevision'
containers: [
{
name: containerAppName
image: containerImage
resources: {
cpu: json(cpuCore)
memory: '${memorySize}Gi'
}
}
]
scale: {
minReplicas: minReplicas
maxReplicas: maxReplicas
}
}
}
}
However this is following an admin/password approach. For using managed identity, firstly do I need to put a registry entry in there?
``` registries: [
{
server: '${registryName}.azurecr.io'
username: containerRegistry.listCredentials().username
passwordSecretRef: 'container-registry-password'
}
]
If so, the listCredentials().username obviously won't work with admin/password disabled. Secondly, what would I then need in the containers section
containers: [
{
name: containerAppName
image: containerImage ??
resources: {
cpu: json(cpuCore)
memory: '${memorySize}Gi'
}
}
]
As there appears to be no mention of the need for pointing at a repository, or indeed specifying anything other than a password/admin account. Is it that my requirement is impossible as the container app needs to be provisioned before managed identity can be applied to it? Is this a chicken vs egg problem?
You could use a user-assigned identity:
Create a user assigned identity
Grant permission to the user-assigned identity
Assign the identity to the container app
# container-registry-role-assignment.bicep
param registryName string
param roleId string
param principalId string
// Get a reference to the existing registry
resource registry 'Microsoft.ContainerRegistry/registries#2021-06-01-preview' existing = {
name: registryName
}
// Create role assignment
resource roleAssignment 'Microsoft.Authorization/roleAssignments#2020-04-01-preview' = {
name: guid(registry.id, roleId, principalId)
scope: registry
properties: {
roleDefinitionId: subscriptionResourceId('Microsoft.Authorization/roleDefinitions', roleId)
principalId: principalId
principalType: 'ServicePrincipal'
}
}
Then from your main:
param name string
param identityName string
param environmentName string
param containerImage string
param location string = resourceGroup().location
param containerRegistrySubscriptionId string = subscription().subscriptionId
param containerRegistryResourceGroupName string = resourceGroup().name
param containerRegistryName string
// Create identtiy
resource identity 'Microsoft.ManagedIdentity/userAssignedIdentities#2022-01-31-preview' = {
name: identityName
location: location
}
// Assign AcrPull permission
module roleAssignment 'container-registry-role-assignment.bicep' = {
name: 'container-registry-role-assignment'
scope: resourceGroup(containerRegistrySubscriptionId, containerRegistryResourceGroupName)
params: {
roleId: '7f951dda-4ed3-4680-a7ca-43fe172d538d' // AcrPull
principalId: identity.properties.principalId
registryName: containerRegistryName
}
}
// Get a reference to the container app environment
resource managedEnvironment 'Microsoft.App/managedEnvironments#2022-03-01' existing = {
name: environmentName
}
// create the container app
resource containerapp 'Microsoft.App/containerApps#2022-03-01' = {
dependsOn:[
roleAssignment
]
name: name
...
identity: {
type: 'UserAssigned'
userAssignedIdentities: {
'${identity.id}': {}
}
}
properties: {
managedEnvironmentId: managedEnvironment.id
configuration: {
...
registries: [
{
server: '${containerRegistryName}.azurecr.io'
identity: identity.id
}
]
}
template: {
...
containers: [
{
name: name
image: '${containerRegistryName}.azurecr.io/${containerImage}'
...
}
]
}
}
}

Retrieve storage account access keys from a bicep module

is it possible to retrieve a Storage Account's Access Key when deploying the Storage Account via a Bicep module?
My parent bicep creates a storage account using a module file, and it then needs an Access Key but I cannot get it working in a way that's secure:
Parent Bicep
module functionAppStorageModule 'storage-account.bicep' = {
name: 'functionAppStorage'
params: {
...
}
}
resource functionApp 'Microsoft.Web/sites#2021-03-01' = {
name: functionAppName
location: location
kind: 'functionapp'
properties: {
siteConfig: {
appSettings: [
{
name: 'store_key'
value: ???
}
]
}
}
}
I can get it working if I set an output on the module file, and use that output in the parent bicep:
Module Bicep
output storageAccountStr string = 'AccountKey=${listKeys(storageAccount.id, storageAccount.apiVersion).keys[0].value}'
Parent Bicep
properties: {
siteConfig: {
appSettings: [
{
name: 'store_key'
value: functionAppStorageModule.outputs.storageAccountStr
}
]
}
}
But this does not seem secure to me as the key appears in plain text in Deployments' Output section on the Azure portal.
Alternatively, I may work around by deploying the storage account beforehand without the use of a module file, as the use of modules seems to be the issue, but just would like to know what I'm trying above is impossible?
Thanks
If you create the function app in a different module, this should work.
storage-account.bicep file:
param storageAccountName string
...
// Create the storage account
resource storageAccount 'Microsoft.Storage/storageAccounts#2021-09-01' = {
name: storageAccountName
...
}
// return the name
output name string = storageAccount.name
function-app.bicep file:
...
param storageAccountName string
// Get a reference to the existing storage
resource storageAccount 'Microsoft.Storage/storageAccounts#2021-09-01' existing = {
name: storageAccountName
}
// Create the function app
resource functionApp 'Microsoft.Web/sites#2021-03-01' = {
...
properties: {
siteConfig: {
appSettings: [
{
name: 'store_key'
// Here we can securely get the access key
value: 'AccountKey=${listKeys(storageAccount.id, storageAccount.apiVersion).keys[0].value}'
}
]
}
}
}
Then in your main.bicep:
// Create the storage account
module storage 'storage-account.bicep' = {
name: 'functionAppStorage'
params: {
storageAccountName: storageAccountName
...
}
}
// create the function app once the storage has been created
module functionApp 'function-app.bicep' = {
name: 'functionApp'
params: {
...
// depends on storage module
storageAccountName: storage.outputs.name
}
}

How can I create a resource group and add a key vault to it using Bicep?

I'm trying to create a resource group and add a key vault to it.
However, I'm not able to set the new resource group as a target resource group for the key vault.
How can I have the key vault assigned to the newly created resource group without creating a second Bicep module for it?
var loc = 'westus'
// outputs the newly created resource group
module rgCreate 'test.rg.bicep' = {
scope: subscription()
name: 'rgCreate'
params: {
rgLocation: loc
}
}
resource keyVault 'Microsoft.KeyVault/vaults#2021-10-01' = {
name: 'Test'
location: loc
properties: {
enabledForTemplateDeployment: true
sku: {
family: 'A'
name: 'standard'
}
tenantId: tenant().tenantId
}
}
This is the workflow I'm aiming at:
First, if the resource group does not exist, you can't have targetScope = 'resourceGroup' in the main.bicep file. The command az deployment group create will fail:
{"code": "ResourceGroupNotFound", "message": "Resource group '' could not be found."}
You could always trigger the deployment form another resource that already exists (Not sure if it s a good idea tho).
An approach could be to have you main.bicep invoking two modules: one for resource group creation, one for resource creation:
// =========== rg.bicep ===========
// Setting target scope
targetScope = 'subscription'
param name string
param location string
// Creating resource group
resource rg 'Microsoft.Resources/resourceGroups#2021-01-01' = {
name: name
location: location
}
// =========== resources.bicep ===========
param location string = resourceGroup().location
param keyVaultName string
...
//Deploying key vault
resource keyVault 'Microsoft.KeyVault/vaults#2021-10-01' = {
name: keyVaultName
location: location
properties: {
enabledForTemplateDeployment: true
sku: {
family: 'A'
name: 'standard'
}
tenantId: tenant().tenantId
}
}
// Deploying other resources
...
// =========== main.bicep ===========
// Setting target scope
targetScope = 'subscription'
// Parameters
param rgName string = 'test-rg'
param rgLocation string = 'westus'
param keyVaultName string
...
// Creating resource group
module rgModule 'rg.bicep' = {
scope: subscription()
name: '${rgName}-create'
params:{
name: rgName
location: rgLocation
}
}
// Deploying resources in the newly created resource
module resources 'resources.bicep' = {
name: '${rgName}-resources-deployment'
scope: resourceGroup(rgName)
dependsOn: [ rgModule ]
params: {
location: rgLocation
keyVaultName: keyVaultName
...
}
}
To be honest, you could just run az group create command before deploying your template it will make things simpler.

How do i create an access policy for my azure function with bicep?

I have a resource defined in my bicep file like this below, these are two of the resources in my file, i deploy an azure function with the test_resource below, this works fine.
resource test_resource 'Microsoft.Web/sites#2021-03-01' = {
name: resourceName
location: location
kind: 'functionapp'
identity: {
type: 'SystemAssigned'
}
properties: {
httpsOnly: true
serverFarmId: appServicePlan_ResourceId
}
}
and i am attempting to create an access policy as shown below, however i get an error regard the objectId, is there a way to configure the access policy for the above resource, perharps i am passing the wrong id in
"Invalid value found at accessPolicies[0].ObjectId:
but i am passing the test_resource.id as shown in the keyvault_access_policy resource definition.
resource devops_keyvault 'Microsoft.KeyVault/vaults#2021-10-01' existing = {
name: keyVaultName
}
resource keyvault_access_policy 'Microsoft.KeyVault/vaults/accessPolicies#2021-10-01' = {
name: 'add'
parent: devops_keyvault
properties: {
accessPolicies: [
{
objectId: test_resource.id
permissions: {
'keys': []
'secrets': [
'list'
'get'
]
'certificates': [
'list'
'get'
]
}
tenantId: subscription().tenantId
}
]
}
}
Looking at the documentation:
objectId: The object ID of a user, service principal or security group in the Azure Active Directory tenant for the vault. The object ID must be unique for the list of access policies.
In your case it should be the the principal ID of the managed identity:
objectId: test_resource.identity.principalId

App Service Managed Identity and Key Vault the right way

I am currently trying to deploy out a resource group using azure bicep, however, I am running into an issue using key vault for my azure app service. I would like to know if I am actually doing this the correct way. I have a main bicep file that is along the lines of:
// params removed for brevity...
targetScope = 'subscription'
resource rg 'Microsoft.Resources/resourceGroups#2021-04-01' = {
name: 'rg-${appName}-${region}'
location: 'centralus'
}
module appServicePlan 'appplan.bicep' = {
params: {
sku: appServicePlanSku
appName: appName
region: region
}
scope: rg
name: 'AppServicePlanDeploy'
}
module keyVault 'keyvault.bicep' = {
params: {
keyVaultName: keyVaultName
sqlPassword: sqlServerPassword
webSiteManagedId: webSite.outputs.webAppPrincipal
}
scope: rg
name: 'KeyVaultDeploy'
dependsOn: [
webSite
]
}
module ai 'ai.bicep' = {
scope: rg
name: 'ApplicationInsightsDeploy'
params: {
name: appName
region: region
keyVaultName: keyVault.outputs.keyVaultName
}
dependsOn: [
keyVault
]
}
resource kv 'Microsoft.KeyVault/vaults#2019-09-01' existing = {
name: keyVaultName
scope: rg
}
module sql 'sqlserver.bicep' = {
scope: rg
name: 'SQLServerDeploy'
params: {
appName: appName
region: region
sqlPassword: kv.getSecret('sqlPassword')
sqlCapacitity: sqlCapacitity
sqlSku: sqlSku
sqlTier: sqlTier
}
dependsOn: [
keyVault
]
}
module webSite 'site.bicep' = {
params: {
appName: appName
region: region
keyVaultName: keyVaultName
serverFarmId: appServicePlan.outputs.appServicePlanId
}
scope: rg
name: 'AppServiceDeploy'
dependsOn: [
appServicePlan
]
}
My question comes with the implementation of the site.bicep, I started off by passing the secret uri from exported variables and creating the web app last as app insights, sql, etc... all need to be setup and in keyvault before we use their exported secret uri to construct a config. I had something along the lines of:
site.bicep (before):
properties: {
serverFarmId: serverFarmId
keyVaultReferenceIdentity: userAssignedId
siteConfig: {
appSettings: [
{
name: 'APPLICATIONINSIGHTS_CONNECTION_STRING'
value: '#Microsoft.KeyVault(SecretUri=${appInsightsConnectionString})'
}
{
name: 'APPINSIGHTS_INSTRUMENTATIONKEY'
value: '#Microsoft.KeyVault(SecretUri=${appInsightsKey})'
}
]
netFrameworkVersion: 'v5.0'
}
}
The only problem with this implementation is that the key vault MUST be constructed before the website because sql, ai, and the other services will store their values inside of the key vault for the web app to consume by their respective uris. The issue with this is that the KeyVault rightfully so has no idea which azure service to let access it's keys.
My question is the solution of constructing the web app before the key vault the only way to beat this problem? I am using managed identities on the web app and would like to continue doing so if possible. My final solution ended up somewhat like this:
site.bicep (final)
// params removed for brevity...
resource webApplication 'Microsoft.Web/sites#2020-12-01' = {
name: 'app-${appName}-${region}'
location: resourceGroup().location
tags: {
'hidden-related:${resourceGroup().id}/providers/Microsoft.Web/serverfarms/appServicePlan': 'Resource'
}
identity: {
type: 'SystemAssigned'
}
properties: {
serverFarmId: serverFarmId
siteConfig: {
appSettings: [
{
name: 'APPLICATIONINSIGHTS_CONNECTION_STRING'
value: '#Microsoft.KeyVault(SecretUri=${keyVaultName}.vault.azure.net/secrets/aiConnectionString)'
}
{
name: 'APPINSIGHTS_INSTRUMENTATIONKEY'
value: '#Microsoft.KeyVault(SecretUri=${keyVaultName}.vault.azure.net/secrets/aiInstrumentationKey)'
}
{
name: 'AngularConfig:ApplicationInsightsKey'
value: '#Microsoft.KeyVault(SecretUri=${keyVaultName}.vault.azure.net/secrets/aiInstrumentationKey)'
}
]
netFrameworkVersion: 'v5.0'
}
}
}
output webAppPrincipal string = webApplication.identity.principalId
And the KeyVault which will take a dependsOn webSite
keyVault.bicep(final):
resource keyVault 'Microsoft.KeyVault/vaults#2019-09-01' = {
name: keyVaultName
location: resourceGroup().location
properties: {
enabledForDeployment: true
enabledForTemplateDeployment: true
enabledForDiskEncryption: true
enableRbacAuthorization: true
tenantId: subscription().tenantId
sku: {
name: 'standard'
family: 'A'
}
accessPolicies: [
{
tenantId: subscription().tenantId
objectId: webSiteManagedId
permissions: {
keys: [
'get'
]
secrets: [
'list'
'get'
]
}
}
]
}
}
Just treat your accessPolicies as separate resource and add them when both Key Vault and App Service are created. Same applies for Config section and Connection Strings. Check documentation here.
In ARM templates you can achieve same effect using nested templates. In Bicep it is kind the same, but you declare them as separate resource that usually contains parent name (e.g. name: '${kv.name}/add', name: '${webSite.name}/connectionstrings')
Sample
Step 1: Create an App Service without config section
resource webSite 'Microsoft.Web/sites#2020-12-01' = {
name: webSiteName
location: location
properties: {
serverFarmId: hostingPlan.id
siteConfig:{
netFrameworkVersion: 'v5.0'
}
}
identity: {
type:'SystemAssigned'
}
}
Step 2: Create Key Vault without access policies
resource kv 'Microsoft.KeyVault/vaults#2019-09-01' = {
name: keyVaultName
location: location
properties:{
sku:{
family: 'A'
name: 'standard'
}
tenantId: tenantId
enabledForTemplateDeployment: true
accessPolicies:[
]
}
}
Step 3: Create new access policy and reference Web Apps Managed Identity
resource keyVaultAccessPolicy 'Microsoft.KeyVault/vaults/accessPolicies#2021-06-01-preview' = {
name: '${kv.name}/add'
properties: {
accessPolicies: [
{
tenantId: tenantId
objectId: webSite.identity.principalId
permissions: {
keys: [
'get'
]
secrets: [
'list'
'get'
]
}
}
]
}
}
Step 4: Update Webb app config section
resource webSiteConnectionStrings 'Microsoft.Web/sites/config#2020-06-01' = {
name: '${webSite.name}/connectionstrings'
properties: {
DefaultConnection: {
value: '#Microsoft.KeyVault(SecretUri=${keyVaultName}.vault.azure.net/secrets/aiConnectionString)'
type: 'SQLAzure'
}
}
}
One solution could be to use User Assigend Identity instead of System Assigned. Then you would deploy the following:
Deploy a user assigend identity
Key Vault and assign permissions for user assigned identity
Deploy web app with user assigned identity and read / write secrets
User assigned is independent of the resources and so you avoid your chicken and egg problem.
More:
https://learn.microsoft.com/en-us/azure/templates/microsoft.managedidentity/userassignedidentities?tabs=bicep
https://learn.microsoft.com/en-us/azure/active-directory/managed-identities-azure-resources/overview
You should split up three parts of your deployment into separate resources:
Deploy the Key Vault - without any access policies!
Deploy the App Service - with the SystemAssigned Identity, but without the app settings
Deploy the Key Vault Access Policy for the MSI
Deploy the App Settings

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