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Quickstart: Build a Cassandra app with CQLSH and Azure Cosmos DB

  • Статия

APPLIES TO: Cassandra

In this quickstart, you create an Azure Cosmos DB for Apache Cassandra account, and use CQLSH to create a Cassandra database and container. Azure Cosmos DB is a multi-model database service that lets you quickly create and query document, table, key-value, and graph databases with global distribution and horizontal scale capabilities.

Prerequisites

Create a database account

Before you can create a document database, you need to create a Cassandra account with Azure Cosmos DB.

  1. From the Azure portal menu or the Home page, select Create a resource.

  2. On the New page, search for and select Azure Cosmos DB.

  3. On the Azure Cosmos DB page, select Create.

  4. On the API page, select Create under the Cassandra section.

    The API determines the type of account to create. Azure Cosmos DB provides five APIs: NoSQL for document databases, Gremlin for graph databases, MongoDB for document databases, Azure Table, and Cassandra. You must create a separate account for each API.

    Select Cassandra, because in this quickstart you are creating a table that works with the API for Cassandra.

    Learn more about the API for Cassandra.

  5. In the Create Azure Cosmos DB Account page, enter the basic settings for the new Azure Cosmos DB account.

    Setting Value Description
    Subscription Your subscription Select the Azure subscription that you want to use for this Azure Cosmos DB account.
    Resource Group Create new

    Then enter the same name as Account Name    		 Select Create new. Then enter a new resource group name for your account. For simplicity, use the same name as your Azure Cosmos DB account name.
    Account Name Enter a unique name Enter a unique name to identify your Azure Cosmos DB account. Your account URI will be cassandra.cosmos.azure.com appended to your unique account name.

    The account name can use only lowercase letters, numbers, and hyphens (-), and must be between 3 and 31 characters long.
    Location The region closest to your users Select a geographic location to host your Azure Cosmos DB account. Use the location that is closest to your users to give them the fastest access to the data.
    Capacity mode Provisioned throughput or Serverless Select Provisioned throughput to create an account in provisioned throughput mode. Select Serverless to create an account in serverless mode.
    Apply Azure Cosmos DB free tier discount Apply or Do not apply With Azure Cosmos DB free tier, you will get the first 1000 RU/s and 25 GB of storage for free in an account. Learn more about free tier.
    Limit total account throughput Select to limit throughput of the account This is useful if you want to limit the total throughput of the account to a specific value.

    Note

    You can have up to one free tier Azure Cosmos DB account per Azure subscription and must opt-in when creating the account. If you do not see the option to apply the free tier discount, this means another account in the subscription has already been enabled with free tier.

    The new account page for Azure Cosmos DB for Apache Cassandra

  6. In the Global Distribution tab, configure the following details. You can leave the default values for the purpose of this quickstart:

    Setting Value Description
    Geo-Redundancy Disable Enable or disable global distribution on your account by pairing your region with a pair region. You can add more regions to your account later.
    Multi-region Writes Disable Multi-region writes capability allows you to take advantage of the provisioned throughput for your databases and containers across the globe.
    Availability Zones Disable Availability Zones are isolated locations within an Azure region. Each zone is made up of one or more datacenters equipped with independent power, cooling, and networking.

    Note

    The following options are not available if you select Serverless as the Capacity mode:

    • Apply Free Tier Discount
    • Geo-redundancy
    • Multi-region Writes

  7. Optionally you can configure additional details in the following tabs:

    • Networking - Configure access from a virtual network.
    • Backup Policy - Configure either periodic or continuous backup policy.
    • Encryption - Use either service-managed key or a customer-managed key.
    • Tags - Tags are name/value pairs that enable you to categorize resources and view consolidated billing by applying the same tag to multiple resources and resource groups.

  8. Select Review + create.

  9. Review the account settings, and then select Create. It takes a few minutes to create the account. Wait for the portal page to display Your deployment is complete.

    The Azure portal Notifications pane

  10. Select Go to resource to go to the Azure Cosmos DB account page.

Install standalone CQLSH tool

Refer to CQL shell on steps on how to launch a standalone cqlsh tool.

Update your connection string

Now go back to the Azure portal to get your connection string information and copy it into the app. The connection string details enable your app to communicate with your hosted database.

  1. In your Azure Cosmos DB account in the Azure portal, select Connection String.

    View and copy a username from the Azure portal, Connection String page

  2. Use the button on the right side of the screen to copy the USERNAME and PASSWORD value.

  3. In your terminal, set the SSL variables:

    # Export the SSL variables:
export SSL_VERSION=TLSv1_2
export SSL_VALIDATE=false

  4. Connect to Azure Cosmos DB for Apache Cassandra:

    • Paste the USERNAME and PASSWORD value into the command.
    cqlsh <USERNAME>.cassandra.cosmos.azure.com 10350 -u <USERNAME> -p <PASSWORD> --ssl --protocol-version=4

CQL commands to create and run an app

  • Create keyspace
CREATE KEYSPACE IF NOT EXISTS uprofile 
WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'datacenter1' : 1 };
  • Create a table
CREATE TABLE IF NOT EXISTS uprofile.user (user_id int PRIMARY KEY, user_name text, user_bcity text);
  • Insert a row into user table
INSERT INTO  uprofile.user (user_id, user_name, user_bcity) VALUES (101,'johnjoe','New York')

You can also insert data using the COPY command.

COPY uprofile.user(user_id, user_name, user_bcity) FROM '/path to file/fileName.csv' 
WITH DELIMITER = ',' ;
  • Query the user table
SELECT * FROM uprofile.users;

In the Azure portal, open Data Explorer to query, modify, and work with this new data. View the data in Data Explorer - Azure Cosmos DB

Review SLAs in the Azure portal

The Azure portal monitors your Azure Cosmos DB account throughput, storage, availability, latency, and consistency. Charts for metrics associated with an Azure Cosmos DB Service Level Agreement (SLA) show the SLA value compared to actual performance. This suite of metrics makes monitoring your SLAs transparent.

To review metrics and SLAs:

  1. Select Metrics in your Azure Cosmos DB account's navigation menu.

  2. Select a tab such as Latency, and select a timeframe on the right. Compare the Actual and SLA lines on the charts.

    Azure Cosmos DB metrics suite

  3. Review the metrics on the other tabs.

Clean up resources

When you're done with your app and Azure Cosmos DB account, you can delete the Azure resources you created so you don't incur more charges. To delete the resources:

  1. In the Azure portal Search bar, search for and select Resource groups.

  2. From the list, select the resource group you created for this quickstart.

    Select the resource group to delete

  3. On the resource group Overview page, select Delete resource group.

    Delete the resource group

  4. In the next window, enter the name of the resource group to delete, and then select Delete.

Next steps

In this quickstart, you learned how to create an Azure Cosmos DB account with API for Cassandra using CQLSH that creates a Cassandra database and container. You can now import additional data into your Azure Cosmos DB account.

Import Cassandra data into Azure Cosmos DB