Bicep vs Terraform: Simplifying Azure Infrastructure as Code

Bicep vs Terraform: Simplifying Azure Infrastructure as Code

Infrastructure as Code (IaC) is now a standard practice for modern development teams. Using IaC, developers define applications and system infrastructure in version-controlled code, ensuring environments remain consistent across development, staging, and production for Bicep. Without IaC, manual updates can introduce errors and inconsistencies, making deployments risky and time-consuming.

For Azure users, the native IaC solution has long been Azure Resource Manager (ARM) templates. ARM allows you to define infrastructure using JSON files, which are converted into REST API calls to provision resources. These templates include sections for parameters, variables, user-defined functions, resources, and outputs. While mature and fully supported by Microsoft, ARM templates can become verbose and difficult to read, particularly for complex deployments.

Why Terraform Became Popular on Azure

Although ARM templates are powerful, many teams, including ours, preferred Terraform. Terraform uses HashiCorp Configuration Language (HCL), which is concise and developer-friendly. Its state management system keeps track of deployed resources, reducing the risk of drift between code and live infrastructure. Moreover, Terraform is cloud-agnostic, making it ideal for teams managing multi-cloud environments.

Terraform is widely supported and has robust community contributions. For example, it allows modular infrastructure, easy code reuse, and readable configuration files. However, Terraform sometimes lags behind ARM in supporting new Azure features. Workarounds, such as running Azure CLI commands or deploying ARM templates within Terraform, usually address these gaps.

Despite its advantages, Terraform introduces challenges. In one scenario, our App Service backend required optional client certificates—a feature ARM supports with three modes: Require, Allow, and Ignore. Terraform only supported a boolean option, forcing us to implement a workaround. Additionally, inconsistent use of Terraform by the team led to discrepancies between the .tfstate file and actual Azure resources.

Enter Bicep: Microsoft’s Native IaC Language

Bicep is an open-source, domain-specific language built on top of ARM templates. Its syntax is more concise than JSON and leverages the full feature set of Azure immediately. Unlike Terraform, Bicep queries Azure directly to compare the current state of resources with the desired configuration. The what-if command predicts changes without deploying them, similar to Terraform’s plan command.

Bicep supports .bicep files in Visual Studio Code, offering IntelliSense, syntax highlighting, and validation. It also allows decompiling existing ARM templates into Bicep for easier migration. However, its syntax is not as intuitive as Terraform, and the tool is still evolving rapidly. Additionally, Bicep is Azure-only, so cross-cloud deployments require other solutions.

Example: Provisioning an App Service with Bicep

param skuName string = 'F1'
param skuCapacity int = 1
param location string = resourceGroup().location

var appServicePlanName = 'asp-demo1'
var webSiteName = 'app-demo1'

resource appServicePlan 'Microsoft.Web/serverfarms@2020-06-01' = {
  name: appServicePlanName
  location: location
  sku: {
    name: skuName
    capacity: skuCapacity
  }
}

resource appService 'Microsoft.Web/sites@2020-06-01' = {
  name: webSiteName
  location: location
  identity: { type: 'SystemAssigned' }
  properties: {
    serverFarmId: appServicePlan.id
    httpsOnly: true
    siteConfig: { minTlsVersion: '1.2' }
  }
}

Deploying this Bicep file is straightforward with the Azure CLI:

az deployment group what-if \
  --name DemoDeployment1 \
  --resource-group myResourceGroupName \
  --template-file test.bicep

The what-if command previews changes. Removing it will apply the deployment directly.

Terraform Equivalent

variable "skuTier" { type = string default = "Free" }
variable "skuSize" { type = string default = "F1" }
variable "location" { type = string default = "westeurope" }
variable "resource_group_name" { type = string }

locals {
  appServicePlanName = "bicep-demo1-asp"
  webSiteName = "bicep-demo1-app"
}

resource "azurerm_app_service_plan" "AppServicePlan" {
  name = local.appServicePlanName
  location = var.location
  resource_group_name = var.resource_group_name
  kind = "app"
  sku { size = var.skuSize tier = var.skuTier }
}

resource "azurerm_app_service" "AppService" {
  depends_on = [azurerm_app_service_plan.AppServicePlan]
  name = local.webSiteName
  location = var.location
  resource_group_name = var.resource_group_name
  app_service_plan_id = azurerm_app_service_plan.AppServicePlan.id
  https_only = true
  site_config { min_tls_version = "1.2" }
  identity { type = "SystemAssigned" }
}

Terraform’s plan and apply commands handle state locally. Changes to resource names trigger the creation and deletion of resources as needed, offering clear change tracking.

Choosing Between Bicep and Terraform

For teams already comfortable with ARM, Bicep is a natural step forward. It simplifies template creation, reduces JSON complexity, and guarantees immediate access to new Azure features. Terraform remains ideal for multi-cloud deployments or when advanced state management is critical. Both tools benefit from strong community support and documentation.

At the same time, organizations looking to implement these IaC solutions efficiently can leverage consulting and managed services from ZippyOPS. ZippyOPS offers expertise in DevOps, DevSecOps, DataOps, AIOps, MLOps, cloud, microservices, infrastructure, automated operations, and security. Their solutions ensure that your Azure deployments, whether Bicep or Terraform, are robust and scalable. Learn more about ZippyOPS solutions here or explore products and tutorials on YouTube.

For enterprise teams, integrating Bicep or Terraform with professional guidance reduces the risk of human error, improves compliance, and speeds up deployment cycles. In summary, both tools are powerful, and the best choice depends on your team’s workflow and multi-cloud strategy.

Conclusion

Bicep is an emerging IaC tool that simplifies Azure deployments and provides a more readable alternative to ARM templates. Terraform remains highly versatile and cloud-agnostic, making it suitable for multi-cloud environments. By combining these tools with professional services from ZippyOPS, teams can achieve secure, automated, and scalable infrastructure management.

For expert guidance on implementing Bicep, Terraform, or any modern cloud infrastructure, contact ZippyOPS at sales@zippyops.com.