azure_linux_docker_app_service

This terraform example demonstrates how to create a container based Linux App Service with secret management and monitoring.

Features

Managed identity for authentication instead of credentials
Key vault references for accessing secrets from App Service
Email alerts for errors and failed availability checks
Random suffix for resources requiring globally unique name

Azure services

Azure Container Registry

For storing container images

App Service pulls the image from the registry during deployment
Authentication using managed identity

Key Vault

For storing and accessing secrets

Access management using access policies

App Service plan & App Service

For hosting the application. App Service is created into the plan. If you have multiple App Services, it is possible to share the same plan among them.

The application's docker image is deployed from the container registry
Managed identity for accessing the Key Vault & Container registry
Deployment slot for high availability deploys
App service has a lot of settings that can be configured. See all of them here.

Application Insights

User for monitoring, metrics, logs and alerts.

The application should use Application Insights library (e.g. for Node.js) to instrument the application and integrate it with App Insights
Includes availability checks from multiple locations
Email alert for:
- Failed availability checks
- Responses with 5xx response code
- Failed dependencies (e.g. database query or HTTP request fails)

Example usage

Prerequisites

Azure account and a service principal
Resource group
Terraform Azure Provider set up

module "my_app" {
  # Required
  resource_group_name = "my-resource-group"
  alert_email_address = "example@example.com"

  # Optional (with their default values)
  name_prefix            = "azure-app-example--"
  app_service_name      = "appservice"
  app_insights_app_type = "other"
  app_service_plan_tier = "PremiumV2"
  app_service_plan_size = "P1v2"
}

We can create rest of the resources with terraform apply.

An example of a Node.js application can be found in ./example-app directory.

Building an image and deploying to the App Service

Inputs

Name	Description	Type	Default	Required
resource_group_name	Name of the resource group where the resources are deployed	string		yes
alert_email_address	Email address where alerts are sent	string		yes
name_prefix	Name prefix to use for objects that need to be created (only lowercase alphanumeric characters and hyphens allowed)	string	`"azure-app-example--"`	no
app_service_name	Name of the app service to be created. Must be globally unique	string	`"appservice"`	no
app_insights_app_type	Application insights application type	string	`"other"`	no
app_service_plan_tier	App service plan tier	string	`"PremiumV2"`	no
app_service_plan_size	App service plan size	string	`"P1v2"`	no