Tutorial: Using Amazon Cloud Map service discovery with DNS queries - Amazon Cloud Map
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Tutorial: Using Amazon Cloud Map service discovery with DNS queries

This tutorial simulates a microservice architecture with two backend services. The first service will be discoverable using a DNS query. The second service will be discoverable using the Amazon Cloud Map API only.

Note

For the purposes of this tutorial, the resource details, like domain names and IP addresses, are for simulation purposes only. They can't be resolved over the internet.

Prerequisites

The following prerequisites must be met to complete this tutorial successfully.

If you do not have an Amazon Web Services account, use the following procedure to create one.

To sign up for Amazon Web Services
  1. Open http://www.amazonaws.cn/ and choose Sign Up.

  2. Follow the on-screen instructions.

Amazon sends you a confirmation email after the sign-up process is complete. At any time, you can view your current account activity and manage your account by going to http://www.amazonaws.cn/ and choosing My Account.

After you sign up for an Amazon Web Services account, safeguard your administrative user by turning on multi-factor authentication (MFA). For instructions, see Enable a virtual MFA device for an IAM user (console) in the IAM User Guide.

To give other users access to your Amazon Web Services account resources, create IAM users. To secure your IAM users, turn on MFA and only give the IAM users the permissions needed to perform their tasks.

For more information about creating and securing IAM users, see the following topics in the IAM User Guide:

If you have not yet installed the Amazon Command Line Interface, follow the steps at Installing or updating the latest version of the Amazon CLI to install it.

The tutorial requires a command line terminal or shell to run commands. In Linux and macOS, use your preferred shell and package manager.

Note

In Windows, some Bash CLI commands that you commonly use with Lambda (such as zip) are not supported by the operating system's built-in terminals. To get a Windows-integrated version of Ubuntu and Bash, install the Windows Subsystem for Linux.

The tutorial requires a local environment with the dig DNS lookup utility command. For more information about the dig command, see dig - DNS lookup utility.

Step 1: Create an Amazon Cloud Map namespace

In this step, you create a public Amazon Cloud Map namespace. Amazon Cloud Map creates a Route 53 hosted zone on your behalf with this same name. This gives you the ability to discovery the service instances created in this namespace either using public DNS records or by using Amazon Cloud Map API calls.

  1. Sign in to the Amazon Web Services Management Console and open the Amazon Cloud Map console at https://console.amazonaws.cn/cloudmap/.

  2. Choose Create namespace.

  3. For Namespace name, specify cloudmap-tutorial.com.

    Note

    If you were going to use this in production, you'd want to ensure that you specified the name of a domain you owned or had access to. But for the purposes of this tuturial, it's not necessary for it to be an actual domain that's being used.

  4. (Optional) For Namespace description, specify a description for what you intend to use the namespace for.

  5. For Instance discovery, select API calls and public DNS queries.

  6. Leave the rest of the default values and choose Create namespace.

Step 2: Create the Amazon Cloud Map services

In this step, you create two services. The first service will be discoverable using public DNS and API calls. The second service will be discoverable using API calls only.

  1. Sign in to the Amazon Web Services Management Console and open the Amazon Cloud Map console at https://console.amazonaws.cn/cloudmap/.

  2. In the left navigation pane, choose Namespaces to list the namespaces you've created.

  3. From the list of namespaces, select the cloudmap-tutorial.com namespace and choose View details.

  4. In the Services section, choose Create service and do the following to create the first service.

    1. For Service name, enter public-service. The service name will be applied to the DNS records that Amazon Cloud Map creates. The format that is used is <service-name>.<namespace-name>.

    2. For Service Discovery Configuration, select API and DNS.

    3. In the DNS configuration section, for Routing policy, select Multivalue answer routing.

      Note

      The console will translate this to MULTIVALUE after it is selected. For more information about available routing options, see Choosing a routing policy in the Route 53 Developer Guide.

    4. Leave the rest of the default values and choose Create service which will return you to the namespace details page.

  5. In the Services section, choose Create service and do the following to create the second service.

    1. For Service name, enter backend-service.

    2. For Service Discovery Configuration, select API only.

    3. Leave the rest of the default values and choose Create service.

Step 3: Create the Amazon Cloud Map service instances

In this step, you create two service instances, one for each service in our namespace.

  1. Sign in to the Amazon Web Services Management Console and open the Amazon Cloud Map console at https://console.amazonaws.cn/cloudmap/.

  2. From the list of namespaces, select the namespace you created in step 1 and choose View details.

  3. On the namespace details page, from the list of services, select the public-service service and choose View details.

  4. In the Service instances section, choose Register service instance and do the following to create the first service instance.

    1. For Service instance ID, specify first.

    2. For IPv4 address, specify 192.168.2.1.

    3. Leave the rest of the default values and choose Register service instance.

  5. Using the breadcrumb at the top of the page, select cloudmap-tutorial.com to navigate back to the namespace detail page.

  6. On the namespace details page, from the list of services, select the backend-service service and choose View details.

  7. In the Service instances section, choose Register service instance and do the following to create the second service instance.

    1. For Service instance ID, specify second to indicate that this is the second service instance.

    2. For Instance type, select Identifying information for another resource.

    3. For Custom attributes, add a key-value pair with service-name as the key and backend as the value.

    4. Choose Register service instance.

Step 4: Discover the Amazon Cloud Map service instances

Now that the Amazon Cloud Map namespace, services, and service instances are created, you can verify everything is working by discovering the instances. Use the dig command to verify the public DNS settings and the Amazon Cloud Map API to verify the backend service. For more information about the dig command, see dig - DNS lookup utility.

  1. Sign in to the Amazon Web Services Management Console and open the Route 53 console at https://console.amazonaws.cn/route53/.

  2. In the left navigation, choose Hosted zones.

  3. Select the cloudmap-tutorial.com hosted zone. This displays the hosted zone details in a separate pane. Take note of the Name servers associated with your hosted zone as we will use those in the next step.

  4. Using the dig command and one of the Route 53 name servers for your hosted zone, query the DNS records for your service instance.

    dig @hosted-zone-nameserver public-service.cloudmap-tutorial.com

    The ANSWER SECTION in the output should display the IPv4 address you associated with your public-service service.

    ;; ANSWER SECTION: public-service.cloudmap-tutorial.com. 300 IN A 192.168.2.1
  5. Using the Amazon CLI, query the attributes for your second service instances.

    aws servicediscovery discover-instances --namespace-name cloudmap-tutorial.com --service-name backend-service --region region

    The output displays the attributes you associated with the service as key-value pairs.

    { "Instances": [ { "InstanceId": "second", "NamespaceName": "cloudmap-tutorial.com", "ServiceName": "backend-service", "HealthStatus": "UNKNOWN", "Attributes": { "service-name": "backend" } } ], "InstancesRevision": 71462688285136850 }

Step 5: Clean up the resources

Once you have completed the tutorial, you can delete the resources. Amazon Cloud Map requires that you clean them up in reverse order, the service instances first, then the services, and finally the namespace. Amazon Cloud Map will clean up the Route 53 resources on your behalf when you go through these steps.

  1. Sign in to the Amazon Web Services Management Console and open the Amazon Cloud Map console at https://console.amazonaws.cn/cloudmap/.

  2. From the list of namespaces, select the cloudmap-tutorial.com namespace and choose View details.

  3. On the namespace details page, from the list of services, select the public-service service and choose View details.

  4. In the Service instances section, select the first instance and choose Deregister.

  5. Using the breadcrumb at the top of the page, select cloudmap-tutorial.com to navigate back to the namespace detail page.

  6. On the namespace details page, from the list of services, select the public-service service and choose Delete.

  7. Repeat steps 3-6 for the backend-service.

  8. In the left navigation, choose Namespaces.

  9. Select the cloudmap-tutorial.com namespace and choose Delete.

    Note

    Although Amazon Cloud Map cleans up the Route 53 resources on your behalf, you can navigate to the Route 53 console to verify that the cloudmap-tutorial.com hosted zone is deleted.