azure-resource-manager-cosmosdb-dotnet

description	Azure Resource Manager SDK for Cosmos DB in .NET. Use for MANAGEMENT PLANE operations: creating/managing Cosmos DB accounts, databases, containers, throughput settings, and RBAC via Azure Resource Manager. NOT for data plane operations (CRUD on documents) - use Microsoft.Azure.Cosmos for that. Triggers: "Cosmos DB account", "create Cosmos account", "manage Cosmos resources", "ARM Cosmos", "CosmosDBAccountResource", "provision Cosmos DB".
name	azure-resource-manager-cosmosdb-dotnet
package	Azure.ResourceManager.CosmosDB
source_file	SKILL.md
title	Azure.ResourceManager.CosmosDB (.NET)

Azure.ResourceManager.CosmosDB (.NET)

Management plane SDK for provisioning and managing Azure Cosmos DB resources via Azure Resource Manager.

⚠️ Management vs Data Plane

• This SDK (Azure.ResourceManager.CosmosDB): Create accounts, databases, containers, configure throughput, manage RBAC
• Data Plane SDK (Microsoft.Azure.Cosmos): CRUD operations on documents, queries, stored procedures execution

Installation

dotnet add package Azure.ResourceManager.CosmosDB
dotnet add package Azure.Identity

Current Versions: Stable v1.4.0, Preview v1.4.0-beta.13

Environment Variables

AZURE_SUBSCRIPTION_ID=<your-subscription-id>
# For service principal auth (optional)
AZURE_TENANT_ID=<tenant-id>
AZURE_CLIENT_ID=<client-id>
AZURE_CLIENT_SECRET=<client-secret>

Authentication

using Azure.Identity;
using Azure.ResourceManager;
using Azure.ResourceManager.CosmosDB;

// Always use DefaultAzureCredential
var credential = new DefaultAzureCredential();
var armClient = new ArmClient(credential);

// Get subscription
var subscriptionId = Environment.GetEnvironmentVariable("AZURE_SUBSCRIPTION_ID");
var subscription = armClient.GetSubscriptionResource(
    new ResourceIdentifier($"/subscriptions/{subscriptionId}"));

Resource Hierarchy

ArmClient
└── SubscriptionResource
    └── ResourceGroupResource
        └── CosmosDBAccountResource
            ├── CosmosDBSqlDatabaseResource
            │   └── CosmosDBSqlContainerResource
            │       ├── CosmosDBSqlStoredProcedureResource
            │       ├── CosmosDBSqlTriggerResource
            │       └── CosmosDBSqlUserDefinedFunctionResource
            ├── CassandraKeyspaceResource
            ├── GremlinDatabaseResource
            ├── MongoDBDatabaseResource
            └── CosmosDBTableResource

Core Workflow

1. Create Cosmos DB Account

using Azure.ResourceManager.CosmosDB;
using Azure.ResourceManager.CosmosDB.Models;

// Get resource group
var resourceGroup = await subscription
    .GetResourceGroupAsync("my-resource-group");

// Define account
var accountData = new CosmosDBAccountCreateOrUpdateContent(
    location: AzureLocation.EastUS,
    locations: new[]
    {
        new CosmosDBAccountLocation
        {
            LocationName = AzureLocation.EastUS,
            FailoverPriority = 0,
            IsZoneRedundant = false
        }
    })
{
    Kind = CosmosDBAccountKind.GlobalDocumentDB,
    ConsistencyPolicy = new ConsistencyPolicy(DefaultConsistencyLevel.Session),
    EnableAutomaticFailover = true
};

// Create account (long-running operation)
var accountCollection = resourceGroup.Value.GetCosmosDBAccounts();
var operation = await accountCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-cosmos-account",
    accountData);

CosmosDBAccountResource account = operation.Value;

2. Create SQL Database

var databaseData = new CosmosDBSqlDatabaseCreateOrUpdateContent(
    new CosmosDBSqlDatabaseResourceInfo("my-database"));

var databaseCollection = account.GetCosmosDBSqlDatabases();
var dbOperation = await databaseCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-database",
    databaseData);

CosmosDBSqlDatabaseResource database = dbOperation.Value;

3. Create SQL Container

var containerData = new CosmosDBSqlContainerCreateOrUpdateContent(
    new CosmosDBSqlContainerResourceInfo("my-container")
    {
        PartitionKey = new CosmosDBContainerPartitionKey
        {
            Paths = { "/partitionKey" },
            Kind = CosmosDBPartitionKind.Hash
        },
        IndexingPolicy = new CosmosDBIndexingPolicy
        {
            Automatic = true,
            IndexingMode = CosmosDBIndexingMode.Consistent
        },
        DefaultTtl = 86400 // 24 hours
    });

var containerCollection = database.GetCosmosDBSqlContainers();
var containerOperation = await containerCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-container",
    containerData);

CosmosDBSqlContainerResource container = containerOperation.Value;

4. Configure Throughput

// Manual throughput
var throughputData = new ThroughputSettingsUpdateData(
    new ThroughputSettingsResourceInfo
    {
        Throughput = 400
    });

// Autoscale throughput
var autoscaleData = new ThroughputSettingsUpdateData(
    new ThroughputSettingsResourceInfo
    {
        AutoscaleSettings = new AutoscaleSettingsResourceInfo
        {
            MaxThroughput = 4000
        }
    });

// Apply to database
await database.CreateOrUpdateCosmosDBSqlDatabaseThroughputAsync(
    WaitUntil.Completed,
    throughputData);

5. Get Connection Information

// Get keys
var keys = await account.GetKeysAsync();
Console.WriteLine($"Primary Key: {keys.Value.PrimaryMasterKey}");

// Get connection strings
var connectionStrings = await account.GetConnectionStringsAsync();
foreach (var cs in connectionStrings.Value.ConnectionStrings)
{
    Console.WriteLine($"{cs.Description}: {cs.ConnectionString}");
}

Key Types Reference

Type	Purpose
ArmClient	Entry point for all ARM operations
CosmosDBAccountResource	Represents a Cosmos DB account
CosmosDBAccountCollection	Collection for account CRUD
CosmosDBSqlDatabaseResource	SQL API database
CosmosDBSqlContainerResource	SQL API container
CosmosDBAccountCreateOrUpdateContent	Account creation payload
CosmosDBSqlDatabaseCreateOrUpdateContent	Database creation payload
CosmosDBSqlContainerCreateOrUpdateContent	Container creation payload
ThroughputSettingsUpdateData	Throughput configuration

Best Practices

1. Use WaitUntil.Completed for operations that must finish before proceeding
2. Use WaitUntil.Started when you want to poll manually or run operations in parallel
3. Always use DefaultAzureCredential — never hardcode keys
4. Handle RequestFailedException for ARM API errors
5. Use CreateOrUpdateAsync for idempotent operations
6. Navigate hierarchy via Get* methods (e.g., account.GetCosmosDBSqlDatabases())

Error Handling

using Azure;

try
{
    var operation = await accountCollection.CreateOrUpdateAsync(
        WaitUntil.Completed, accountName, accountData);
}
catch (RequestFailedException ex) when (ex.Status == 409)
{
    Console.WriteLine("Account already exists");
}
catch (RequestFailedException ex)
{
    Console.WriteLine($"ARM Error: {ex.Status} - {ex.ErrorCode}: {ex.Message}");
}

Reference Files

File	When to Read
references/account-management.md	Account CRUD, failover, keys, connection strings, networking
references/sql-resources.md	SQL databases, containers, stored procedures, triggers, UDFs
references/throughput.md	Manual/autoscale throughput, migration between modes

Related SDKs

SDK	Purpose	Install
Microsoft.Azure.Cosmos	Data plane (document CRUD, queries)	dotnet add package Microsoft.Azure.Cosmos
Azure.ResourceManager.CosmosDB	Management plane (this SDK)	dotnet add package Azure.ResourceManager.CosmosDB