pulumi-arm-to-pulumi

SKILL.md

IMPORTANT: PLAN ADJUSTMENT REQUIRED

If you have already generated a migration plan before loading this skill, you MUST:

Review your existing plan against the workflows and requirements in this skill

Identify any gaps, missing steps, or incorrect assumptions

Update and revise your plan to align with this skill's guidance

Communicate the adjusted plan to the user before proceeding

CRITICAL SUCCESS REQUIREMENTS

The migration output MUST meet all of the following:

Complete Resource Coverage

Every ARM template resource MUST:

Be represented in the Pulumi program OR

Be explicitly justified in the final report.

Successful Deployment

The produced Pulumi program must be structurally valid and capable of a successful pulumi preview (assuming proper config).

Zero-Diff Import Validation (if importing existing resources)

After import, pulumi preview must show:

NO updates

NO replaces

NO creates

NO deletes

Any diffs must be resolved using the Preview Resolution Workflow. See arm-import.md.

Final Migration Report

Always output a formal migration report suitable for a Pull Request.

Include:

ARM → Pulumi resource mapping

Provider decisions (azure-native vs azure)

Behavioral differences

Missing or manually required steps

Validation instructions

WHEN INFORMATION IS MISSING

If a user-provided ARM template is incomplete, ambiguous, or missing artifacts, ask targeted questions before generating Pulumi code.

If there is ambiguity on how to handle a specific resource property on import, ask targeted questions before altering Pulumi code.

MIGRATION WORKFLOW

Follow this workflow exactly and in this order:

1. INFORMATION GATHERING

1.1 Verify Azure Credentials

Running Azure CLI commands (e.g., az resource list, az resource show). Requires initial login using ESC and az login

If the user has already provided an ESC environment, use it.

If no ESC environment is specified, ask the user which ESC environment to use before proceeding with Azure CLI commands.

Setting up Azure CLI using ESC:

ESC environments can provide Azure credentials through environment variables or Azure CLI configuration

Login to Azure using ESC to provide credentials, e.g: pulumi env run {org}/{project}/{environment} -- bash -c 'az login --service-principal -u "$ARM_CLIENT_ID" --tenant "$ARM_TENANT_ID" --federated-token "$ARM_OIDC_TOKEN"'. ESC is not required after establishing the session

Verify credentials are working: az account show

Confirm subscription: az account list --query "[].{Name:name, SubscriptionId:id, IsDefault:isDefault}" -o table

For detailed ESC information: Load the pulumi-esc skill by calling the tool "Skill" with name = "pulumi-esc"

1.2 Analyze ARM Template Structure

ARM templates do not have the concept of "stacks" like CloudFormation. Read the ARM template JSON file directly:

# View template structure
cat template.json | jq '.resources[] | {type: .type, name: .name}'

# View parameters
cat template.json | jq '.parameters'

# View variables
cat template.json | jq '.variables'

Extract:

Resource types and names

Parameters and their default values

Variables and expressions

Dependencies (dependsOn arrays)

Nested templates or linked templates

Copy loops (iteration constructs)

Conditional deployments (condition property)

Documentation: ARM Template Structure

1.3 Build Resource Inventory (if importing existing resources)

If the ARM template has already been deployed and you're importing existing resources:

# List all resources in a resource group
az resource list \
  --resource-group <resource-group-name> \
  --output json

# Get specific resource details
az resource show \
  --ids <resource-id> \
  --output json

# Query specific properties using JMESPath
az resource show \
  --ids <resource-id> \
  --query "{name:name, location:location, properties:properties}" \
  --output json

Documentation: Azure CLI Documentation

2. CODE CONVERSION (ARM → PULUMI)

IMPORTANT: ARM to Pulumi conversion requires manual translation. There is NO automated conversion tool for ARM templates. You are responsible for the complete conversion.

Key Conversion Principles

Provider Strategy:

Default: Use @pulumi/azure-native for full Azure Resource Manager API coverage

Fallback: Use @pulumi/azure (classic provider) when azure-native doesn't support specific features or when you need simplified abstractions

Documentation:

Azure Native Provider

Azure Classic Provider

Language Support:

TypeScript/JavaScript: Most common, excellent IDE support

Python: Great for data teams and ML workflows

C#: Natural fit for .NET teams

Go: High performance, strong typing

Java: Enterprise Java teams

YAML: Simple declarative approach

Choose based on user preference or existing codebase

Complete Coverage:

Convert ALL resources in the ARM template

Preserve all conditionals, loops, and dependencies

Maintain parameter and variable logic

Follow conversion patterns in arm-conversion-patterns.md.

arm-conversion-patterns.md provides:

Parameters, variables, and outputs mapping

Copy loops, conditionals, and dependsOn translation

Nested templates → ComponentResource

Azure Classic provider examples (VNet, App Service)

TypeScript output handling and common pitfalls

3. RESOURCE IMPORT (EXISTING RESOURCES) - OPTIONAL

After conversion, you can optionally import existing resources to be managed by Pulumi. If the user does not request this, suggest it as a follow-up step to conversion.

CRITICAL: When the user requests importing existing Azure resources into Pulumi, see arm-import.md for detailed import procedures and zero-diff validation workflows.

arm-import.md provides:

Inline import ID patterns and examples

Azure Resource ID format conventions

Child resource handling (e.g., WebAppApplicationSettings)

Preview Resolution Workflow for achieving zero-diff after import

Step-by-step debugging for property conflicts

Key Import Principles

Inline Import Approach:

Use import resource option with Azure Resource IDs

No separate import tool (unlike pulumi-cdk-importer)

Azure Resource IDs:

Follow predictable pattern: /subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/{resourceProviderNamespace}/{resourceType}/{resourceName}

Can be generated by convention or queried via Azure CLI

Zero-Diff Validation:

Run pulumi preview after import

Resolve all diffs using Preview Resolution Workflow

Goal: NO updates, replaces, creates, or deletes

4. PULUMI CONFIGURATION

Set up stack configuration matching ARM template parameters:

# Set Azure region
pulumi config set azure-native:location eastus --stack dev

# Set application parameters
pulumi config set storageAccountName mystorageaccount --stack dev

# Set secret parameters
pulumi config set --secret adminPassword MyS3cr3tP@ssw0rd --stack dev

5. VALIDATION

After achieving zero diff in preview (if importing), validate the migration:

Review all exports:

pulumi stack output

Verify resource relationships:

pulumi stack graph

Test application functionality (if applicable)

Document any manual steps required post-migration

WORKING WITH THE USER

If the user asks for help planning or performing an ARM to Pulumi migration, use the information above to guide the user through the conversion and import process.

FOR DETAILED DOCUMENTATION

When the user wants additional information, use the web-fetch tool to get content from the official Pulumi documentation:

ARM Migration Guide: https://www.pulumi.com/docs/iac/adopting-pulumi/migrating-to-pulumi/from-arm/

Azure Native Provider: https://www.pulumi.com/registry/packages/azure-native/

Azure Classic Provider: https://www.pulumi.com/registry/packages/azure/

Microsoft Azure Documentation:

ARM Template Reference: https://learn.microsoft.com/en-us/azure/azure-resource-manager/templates/

Azure CLI Reference: https://learn.microsoft.com/en-us/cli/azure/

Azure Resource IDs: https://learn.microsoft.com/en-us/azure/azure-resource-manager/templates/template-functions-resource

OUTPUT FORMAT (REQUIRED)

When performing a migration, always produce:

Overview (high-level description)

Migration Plan Summary

ARM template resources identified

Conversion strategy (language, providers)

Import approach (if applicable)

Pulumi Code Outputs (organized by file)

Main program file

Component resources (if any)

Configuration instructions

Resource Mapping Table (ARM → Pulumi)

ARM resource type → Pulumi resource type

ARM resource name → Pulumi logical name

Import ID (if importing)

Preview Resolution Notes (if importing)

Diffs encountered

Resolution strategy applied

Properties ignored vs. added

Final Migration Report (PR-ready)

Summary of changes

Testing instructions

Known limitations

Next steps

Configuration Setup

Required config values

Example pulumi config set commands

Keep code syntactically valid and clearly separated by files.