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Quickstart: Scaling services deployed with the azd Python web templates using Bicep

  • Grein

The Python web azd templates allow you to quickly create a new web application and deploy it to Azure. The azd templates were designed to use low-cost Azure service options. Undoubtedly, you'll want to adjust the service levels (or skus) for each of the services defined in the template for your scenario.

In this Quickstart, you'll update the appropriate bicep template files to scale up existing services and add new services to your deployment. Then, you'll run the azd provision command and view the change you made to the Azure deployment.

Prerequisites

An Azure subscription - Create one for free

You must have the following installed on your local computer:

Deploy a template

To begin, you need a working azd deployment. Once you have that in place, you're able to modify the Bicep files generated by the azd template.

  1. Follow steps 1 through 7 in the Quickstart article. In step 2, use the azure-django-postgres-flexible-appservice template. For your convenience, here's the entire sequence of commands to issue from the command line:

    mkdir azdtest
cd azdtest
azd init --template azure-django-postgres-flexible-appservice
azd auth login
azd up

    Once azd up finishes, open the Azure portal, navigate to the Azure App Service that was deployed in your new Resource Group and take note of the App Service pricing plan (see the App Service plan's Overview page, Essentials section, "Pricing plan" value).

  2. In step 1 of the Quickstart article, you were instructed to create the azdtest folder. Open that folder in Visual Studio Code.

  3. In the Explorer pane, navigate to the infra folder. Observe the subfolders and files in the infra folder.

    The main.bicep file orchestrates the creation of all the services deployed when performing an azd up or azd provision. It calls into other files, like db.bicep and web.bicep, which in turn call into files contained in the \core subfolder.

    The \core subfolder is a deeply nested folder structure containing bicep templates for many Azure services. Some of the files in the \core subfolder are referenced by the three top level bicep files (main.bicep, db.bicep and web.bicep) and some aren't used at all in this project.

Scale a service by modifying its Bicep properties

You can scale an existing resource in your deployment by changing its SKU. To demonstrate this, you'll change the App Service plan from the "Basic Service plan" (which is designed for apps with lower traffic requirements and don't need advanced auto scale and traffic management features) to the "Standard Service plan", which is designed for running production workloads.

Note

Not all SKU changes can be made after the fact. Some research may be necessary to better understand your scaling options.

  1. Open the web.bicep file and locate the appService module definition. In particular, look for the property setting:

       sku: {
      name: 'B1'
   }

    Change the value from B1 to S1 as follows:

       sku: {
      name: 'S1'
   }

    Important

    As a result of this change, the price per hour will increase slightly. Details about the different service plans and their associated costs can be found on the App Service pricing page.

  2. Assuming you already have the application deployed in Azure, use the following command to deploy changes to the infrastructure while not redeploying the application code itself.

    azd provision

    You shouldn't be prompted for a location and subscription. Those values are saved in the .azure<environment-name>.env file where <environment-name> is the environment name you provided during azd init.

  3. When azd provision is complete, confirm your web application still works. Also find the App Service Plan for your Resource Group and confirm that the Pricing Plan is set to the Standard Service Plan (S1).

Add a new service definition with Bicep

You can add a new resource to your deployment by making larger changes to the Bicep in the project. To demonstrate this, you'll add an instance of Azure Cache for Redis to your existing deployment in preparation for a fictitious new feature you plan to add at some future date.

Important

As a result of this change, you will be paying for an instance of Azure Cache for Redis until you delete the resource in the Azure portal or using azd down. Details about the different service plans and their associated costs can be found on the Azure Cache for Redis pricing page.

  1. Create a new file in the infra folder named redis.bicep. Copy and paste the following code into the new file:

    param name string
param location string = resourceGroup().location
param tags object = {}
param keyVaultName string
param connStrKeyName string
param passwordKeyName string
param primaryKeyKeyName string

@allowed([
  'Enabled'
  'Disabled'
])
param publicNetworkAccess string = 'Enabled'

@allowed([
  'C'
  'P'
])
param skuFamily string = 'C'

@allowed([
  0
  1
  2
  3
  4
  5
  6
])
param skuCapacity int = 1
@allowed([
  'Basic'
  'Standard'
  'Premium'
])
param skuName string = 'Standard'

param saveKeysToVault bool = true

resource redis 'Microsoft.Cache/redis@2020-12-01' = {
  name: name
  location: location
  properties: {
    sku: {
      capacity: skuCapacity
      family: skuFamily
      name: skuName
    }
    publicNetworkAccess: publicNetworkAccess
    enableNonSslPort: true    
  }
  tags: tags
}

resource keyVault 'Microsoft.KeyVault/vaults@2022-07-01' existing = {
  name: keyVaultName
}

resource redisKey 'Microsoft.KeyVault/vaults/secrets@2022-07-01' = if (saveKeysToVault) {
  name: primaryKeyKeyName
  parent: keyVault
  properties: {
    value: redis.listKeys().primaryKey
  }
}

resource redisConnStr 'Microsoft.KeyVault/vaults/secrets@2018-02-14' = if (saveKeysToVault) {
  name: connStrKeyName
  parent: keyVault
  properties: {
    value: '${name}.redis.cache.windows.net,abortConnect=false,ssl=true,password=${redis.listKeys().primaryKey}'
  }
}
resource redisPassword 'Microsoft.KeyVault/vaults/secrets@2018-02-14' = if (saveKeysToVault) {
  name: passwordKeyName
  parent: keyVault
  properties: {
    value: redis.listKeys().primaryKey
  }
}

output REDIS_ID string = redis.id
output REDIS_HOST string = redis.properties.hostName

  2. Modify the main.bicep file to create an instance of the "redis" resource.

    In the main.bicep file, add the following code below the ending curly braces associated with the Web frontend section and above the secrets section.

    // Caching server
module redis 'redis.bicep' = {
  name: 'redis'
  scope: resourceGroup
  params: {
    name: replace('${take(prefix, 19)}-rds', '--', '-')
    location: location
    tags: tags
    keyVaultName: keyVault.outputs.name
    connStrKeyName: 'RedisConnectionString'
    passwordKeyName: 'RedisPassword'
    primaryKeyKeyName: 'RedisPrimaryKey'
    publicNetworkAccess: 'Enabled'
    skuFamily: 'C'
    skuCapacity: 1
    skuName: 'Standard'
    saveKeysToVault: true
  }
}

  3. Add output values to the bottom of the file:

    output REDIS_ID string = redis.outputs.REDIS_ID
output REDIS_HOST string = redis.outputs.REDIS_HOST

  4. Confirm that the entire main.bicep file is identical to the following code:

    targetScope = 'subscription'

@minLength(1)
@maxLength(64)
@description('Name which is used to generate a short unique hash for each resource')
param name string

@minLength(1)
@description('Primary location for all resources')
param location string

@secure()
@description('DBServer administrator password')
param dbserverPassword string

@secure()
@description('Secret Key')
param secretKey string

@description('Id of the user or app to assign application roles')
param principalId string = ''

var resourceToken = toLower(uniqueString(subscription().id, name, location))
var prefix = '${name}-${resourceToken}'
var tags = { 'azd-env-name': name }

resource resourceGroup 'Microsoft.Resources/resourceGroups@2021-04-01' = {
  name: '${name}-rg'
  location: location
  tags: tags
}

// Store secrets in a keyvault
module keyVault './core/security/keyvault.bicep' = {
  name: 'keyvault'
  scope: resourceGroup
  params: {
    name: '${take(replace(prefix, '-', ''), 17)}-vault'
    location: location
    tags: tags
    principalId: principalId
  }
}

module db 'db.bicep' = {
  name: 'db'
  scope: resourceGroup
  params: {
    name: 'dbserver'
    location: location
    tags: tags
    prefix: prefix
    dbserverDatabaseName: 'relecloud'
    dbserverPassword: dbserverPassword
  }
}

// Monitor application with Azure Monitor
module monitoring 'core/monitor/monitoring.bicep' = {
  name: 'monitoring'
  scope: resourceGroup
  params: {
    location: location
    tags: tags
    applicationInsightsDashboardName: '${prefix}-appinsights-dashboard'
    applicationInsightsName: '${prefix}-appinsights'
    logAnalyticsName: '${take(prefix, 50)}-loganalytics' // Max 63 chars
  }
}

// Web frontend
module web 'web.bicep' = {
  name: 'web'
  scope: resourceGroup
  params: {
    name: replace('${take(prefix, 19)}-appsvc', '--', '-')
    location: location
    tags: tags
    applicationInsightsName: monitoring.outputs.applicationInsightsName
    keyVaultName: keyVault.outputs.name
    appCommandLine: 'entrypoint.sh'
    pythonVersion: '3.12'
    dbserverDomainName: db.outputs.dbserverDomainName
    dbserverUser: db.outputs.dbserverUser
    dbserverDatabaseName: db.outputs.dbserverDatabaseName
  }
}

// Caching server
module redis 'redis.bicep' = {
  name: 'redis'
  scope: resourceGroup
  params: {
    name: replace('${take(prefix, 19)}-rds', '--', '-')
    location: location
    tags: tags
    keyVaultName: keyVault.outputs.name
    connStrKeyName: 'RedisConnectionString'
    passwordKeyName: 'RedisPassword'
    primaryKeyKeyName: 'RedisPrimaryKey'
    publicNetworkAccess: 'Enabled'
    skuFamily: 'C'
    skuCapacity: 1
    skuName: 'Standard'
    saveKeysToVault: true
  }
}

var secrets = [
  {
    name: 'DBSERVERPASSWORD'
    value: dbserverPassword
  }
  {
    name: 'SECRETKEY'
    value: secretKey
  }
]

@batchSize(1)
module keyVaultSecrets './core/security/keyvault-secret.bicep' = [for secret in secrets: {
  name: 'keyvault-secret-${secret.name}'
  scope: resourceGroup
  params: {
    keyVaultName: keyVault.outputs.name
    name: secret.name
    secretValue: secret.value
  }
}]

output AZURE_LOCATION string = location
output AZURE_KEY_VAULT_ENDPOINT string = keyVault.outputs.endpoint
output AZURE_KEY_VAULT_NAME string = keyVault.outputs.name
output APPLICATIONINSIGHTS_NAME string = monitoring.outputs.applicationInsightsName
output BACKEND_URI string = web.outputs.uri

output REDIS_ID string = redis.outputs.REDIS_ID
output REDIS_HOST string = redis.outputs.REDIS_HOST

  5. Make sure all your changes are saved, then use the following command to update your provisioned resources on Azure:

    azd provision

    Note

    Depending on many factors, adding an instance of Azure Cache for Redis to the existing deployment could take a long time. In testing, we experienced execution times in excess of 20 minutes. As long as you do not see any errors, allow the process to continue until complete.

  6. When azd provision completes, open the Azure portal, navigate to the Resource Group for your deployment, and in the list of services confirm you now have an instance of Azure Cache for Redis.

This concludes the Quickstart, however there are many Azure services that can help you build more scalable and production-ready applications. A great place to start would be to learn about Azure API Management, Azure Front Door, Azure CDN, and Azure Virtual Network, to name a few.

Clean up resources

Clean up the resources created by the template by running the azd down command.

azd down

The azd down command deletes the Azure resources and the GitHub Actions workflow. When prompted, agree to deleting all resources associated with the resource group.

You can also delete the azdtest folder, or use it as the basis for your own application by modifying the files of the project.

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