cosmosdb-scaling-with-azure-functions

An example of how to use Azure Functions to scale a Cosmos DB collection.

• Tutorial: scaling_tutorial.pdf
• Function Code: CosmosScaling.cs

Requirements

You will need an Azure account from which you can provision an instance of Cosmos DB (SQL API preffered), and an Azure Function App.

What does it do?

NOTICE: The guide assumes the user has a basic understanding of Microsoft Azure and Visual Studio

This guide will walk you through creating an Azure function that scales up throughput on a Cosmos DB collection when a throttling (429 error) alert is fired. The guide will step through the following processes:

1. Write an azure function to scale throughput on a collection.
2. Publish the function to Azure.
3. connect the function to a CosmosDB account alert using a webhook.

For your consideration

The solution only scales up, but can be used to scale down if you supply a negative value for the CosmosDB_RUIncrement settings attribute. It is suggested to implement a limit on scaling to keep your bill manageable. Alerts are set at the account level meaning that this function will be triggered any time a resource under the account, for which the alert was set, is throttled.