Add availability zone check for Azure Managed Instance for Apache Cassandra by Copilot · Pull Request #8 · BenjaminEngeset/PSRule.Rules.Azure

Copilot · 2025-11-12T11:37:20Z

PR Summary

Implements Azure.MICassandra.AvailabilityZone (AZR-000504) to validate that Managed Instance for Apache Cassandra data centers enable availability zones in supported regions.

Rule: Azure.MICassandra.AvailabilityZone (AZR-000504)
Resource Types: Microsoft.DocumentDB/cassandraClusters, Microsoft.DocumentDB/cassandraClusters/dataCenters
API Version: 2024-11-15 (latest stable)
Release: GA
Rule Set: 2025_12
Pillar: Reliability
Category: RE:05 Redundancy
Reviewed: 2025-11-13

The rule checks that Azure Managed Instance for Apache Cassandra data centers have properties.availabilityZone set to true in regions that support availability zones. The rule automatically passes for regions that don't support availability zones.

Key Features

Dedicated Rule File: Created Azure.MICassandra.Rule.ps1 for Managed Instance for Apache Cassandra rules
Helper Function: Implemented GetCassandraDataCenter function to handle both cluster and datacenter resources (similar to GetMariaDBFirewallRule)
Dual Resource Support: Rule evaluates both parent clusters (checking their nested datacenters) and standalone datacenter resources
Region-Aware: Uses VMSS zone mappings for region capability detection; auto-passes for regions without AZ support
Latest Stable API: Uses API version 2024-11-15 for all resources

Test Coverage

Comprehensive test scenarios include:

Nested resources: Clusters with datacenters declared under the resources property (positioned at top of test file)
Standalone datacenters: Top-level datacenter resources (positioned at bottom of test file)
Mixed scenarios: Clusters with multiple datacenters (some with AZ, some without)
Unsupported regions: Datacenters in regions without availability zone support (e.g., westindia)
All combinations: With AZ enabled, without AZ enabled, in supported/unsupported regions

Test structure follows Cosmos.json organization pattern:

Nested resources first, standalone child resources last
Consistent naming: clusters as micassandra-{letter}, datacenters as datacenter-{letter} (sequential)
Complete metadata: ResourceId, Id, ResourceName, Name, ResourceGroupName, Type, ApiVersion, SubscriptionId
Reason assertions matching actual error messages

Test Results: 3 failures (expected) + 6 passes (expected) = 9 resources validated with reason assertions ✅

Files Changed

New: src/PSRule.Rules.Azure/rules/Azure.MICassandra.Rule.ps1 (with helper function)
New: tests/PSRule.Rules.Azure.Tests/Azure.MICassandra.Tests.ps1 (comprehensive test coverage with reason assertions)
New: tests/PSRule.Rules.Azure.Tests/Resources.MICassandra.json (9 test resources using API version 2024-11-15)
New: docs/en/rules/Azure.MICassandra.AvailabilityZone.md (rule documentation with ARM, Bicep examples using API version 2024-11-15)
Updated: src/PSRule.Rules.Azure/en/PSRule-rules.psd1 (localization strings)
Updated: docs/changelog.md (change log entry)

Example

resource dataCenter 'Microsoft.DocumentDB/cassandraClusters/dataCenters@2024-11-15' = {
  properties: {
    availabilityZone: true  // Required in supported regions
    // ...
  }
}

PR Checklist

PR has a meaningful title
Summarized changes
Change is not breaking
This PR is ready to merge and is not Work in Progress
Rule changes
- Unit tests created/ updated
- Rule documentation created/ updated
- Link to a filed issue ([RULE] Check for availability zones for Azure Managed Instance for Apache Cassandra Azure/PSRule.Rules.Azure#3592)
- Change log has been updated with change under unreleased section

Original prompt

Check for availability zones for Azure Managed Instance for Apache Cassandra Azure#3592

Created from VS Code via the GitHub Pull Request extension.

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Co-authored-by: BenjaminEngeset <99641908+BenjaminEngeset@users.noreply.github.com>

BenjaminEngeset · 2025-11-12T12:07:45Z

docs/en/rules/index.md

 AZR-000498 | [Azure.AppConfig.ReplicaLocation](Azure.AppConfig.ReplicaLocation.md) | The replication location determines the country or region where configuration data is stored and processed. | GA
+AZR-000499 | [Azure.Cosmos.MongoEntraID](Azure.Cosmos.MongoEntraID.md) | Cosmos DB accounts should use Entra ID authentication. | GA
+AZR-000502 | [Azure.Cosmos.AvailabilityZone](Azure.Cosmos.AvailabilityZone.md) | Use zone redundant Cosmos DB accounts in supported regions to improve reliability. | GA
+AZR-000503 | [Azure.Cassandra.AvailabilityZone](Azure.Cassandra.AvailabilityZone.md) | Deploy Azure Managed Instance for Apache Cassandra data centers using availability zones in supported regions to ensure high availability and resilience. | GA


@copilot Remove the changes you have done in this file. This file should not be edited as a part of this PR.

Done. Reverted all changes to docs/en/rules/index.md in commit 1c27cec.

BenjaminEngeset · 2025-11-12T12:09:04Z

docs/en/rules/Azure.Cassandra.AvailabilityZone.md

+---
+severity: Important
+pillar: Reliability
+category: RE:05 Regions and availability zones


@copilot RE:05 Redundancy

Updated to RE:05 Redundancy in commit 1c27cec.

…E:05 Redundancy Co-authored-by: BenjaminEngeset <99641908+BenjaminEngeset@users.noreply.github.com>

BenjaminEngeset

@copilot Lets move it out to an own dedicated rule file as the Azure Managed Instance for Apache Cassandra does not really fit into Cosmos DB.

Lets call it Azure.MICassandra.Rule.ps1 and the rule should be named Azure.MICassandra.AvailabliityZone.

Resources file should be Resources.MICassandra.json

… file Co-authored-by: BenjaminEngeset <99641908+BenjaminEngeset@users.noreply.github.com>

Copilot · 2025-11-12T12:56:48Z

@copilot Lets move it out to an own dedicated rule file as the Azure Managed Instance for Apache Cassandra does not really fit into Cosmos DB.

Lets call it Azure.MICassandra.Rule.ps1 and the rule sho...

Done. Moved to dedicated Azure.MICassandra.Rule.ps1 file with rule named Azure.MICassandra.AvailabilityZone. Resources file is now Resources.MICassandra.json and test file is Azure.MICassandra.Tests.ps1. All tests passing. See commit 949104f.

BenjaminEngeset · 2025-11-12T13:39:23Z

src/PSRule.Rules.Azure/rules/Azure.MICassandra.Rule.ps1

+#region Rules
+
+# Synopsis: Deploy Azure Managed Instance for Apache Cassandra data centers using availability zones in supported regions to ensure high availability and resilience.
+Rule 'Azure.MICassandra.AvailabilityZone' -Ref 'AZR-000503' -Type 'Microsoft.DocumentDB/cassandraClusters/dataCenters' -Tag @{ release = 'GA'; ruleSet = '2025_12'; 'Azure.WAF/pillar' = 'Reliability'; } -Labels @{ 'Azure.WAF/maturity' = 'L1' } {


@copilot Change to AZR-000504. AZR-000503 is already taken in another PR.

Updated to AZR-000504 in commit 13f837b.

BenjaminEngeset · 2025-11-13T08:16:19Z