Tutorial: Creating a Service Using Service Discovery

Service discovery has been integrated into the Create Service wizard in the Amazon ECS console. For more information, see Creating a Service.

The following tutorial shows how to create an ECS service containing a Fargate task that uses service discovery with the AWS CLI.

Note

Fargate tasks are only supported in the following Regions:

Region Name	Region
US East (N. Virginia)	us-east-1
US East (Ohio)	us-east-2
US West (N. California)	us-west-1
US West (Oregon)	us-west-2
Asia Pacific (Mumbai)	ap-south-1
EU (Ireland)	eu-west-1
EU (London)	eu-west-2
EU (Frankfurt)	eu-central-1
Asia Pacific (Tokyo)	ap-northeast-1
Canada (Central)	ca-central-1
Asia Pacific (Seoul)	ap-northeast-2
Asia Pacific (Singapore)	ap-southeast-1
Asia Pacific (Sydney)	ap-southeast-2

Topics

Prerequisites
Step 1: Create the Service Discovery Resources
Step 2: Create the Amazon ECS Resources
Step 3: Verify Service Discovery
Step 4: Clean Up

Prerequisites

This tutorial assumes that the following prerequisites have been completed:

The latest version of the AWS CLI is installed and configured. For more information, see Installing the AWS Command Line Interface.
The steps in Setting Up with Amazon ECS have been completed.
Your AWS user has the required permissions specified in the Amazon ECS First Run Wizard IAM policy example.
You have a VPC and security group created to use. For more information, see Tutorial: Creating a VPC with Public and Private Subnets for Your Clusters.

Step 1: Create the Service Discovery Resources

Use the following steps to create your service discovery namespace and service discovery service.

To create the Service Discovery resources

Create a private service discovery namespace named tutorial within one of your existing VPCs:


aws servicediscovery create-private-dns-namespace --name tutorial --vpc vpc-abcd1234 --region us-east-1

Output:

{
    "OperationId": "h2qe3s6dxftvvt7riu6lfy2f6c3jlhf4-je6chs2e"
}

Using the OperationId from the previous output, verify that the private namespace was created successfully. Copy the namespace ID as it is used in subsequent commands.


aws servicediscovery get-operation --operation-id h2qe3s6dxftvvt7riu6lfy2f6c3jlhf4-je6chs2e

Output:

{
    "Operation": {
        "Id": "h2qe3s6dxftvvt7riu6lfy2f6c3jlhf4-je6chs2e",
        "Type": "CREATE_NAMESPACE",
        "Status": "SUCCESS",
        "CreateDate": 1519777852.502,
        "UpdateDate": 1519777856.086,
        "Targets": {
            "NAMESPACE": "ns-uejictsjen2i4eeg"
        }
    }
}

Using the NAMESPACE ID from the previous output, create a service discovery service named myapplication. Copy the service discovery service ID as it is used in subsequent commands:


aws servicediscovery create-service --name myapplication --dns-config 'NamespaceId="ns-uejictsjen2i4eeg",DnsRecords=[{Type="A",TTL="300"}]' --health-check-custom-config FailureThreshold=1 --region us-east-1

Output:

{
    "Service": {
        "Id": "srv-utcrh6wavdkggqtk",
        "Arn": "arn:aws:servicediscovery:region:aws_account_id:service/srv-utcrh6wavdkggqtk",
        "Name": "myapplication",
        "DnsConfig": {
            "NamespaceId": "ns-uejictsjen2i4eeg",
            "DnsRecords": [
                {
                    "Type": "A",
                    "TTL": 300
                }
            ]
        },
        "HealthCheckCustomConfig": {
            "FailureThreshold": 1
        },
        "CreatorRequestId": "e49a8797-b735-481b-a657-b74d1d6734eb"
    }
}

Step 2: Create the Amazon ECS Resources

Use the following steps to create your Amazon ECS cluster, task definition, and service.

To create Amazon ECS resources

Create an Amazon ECS cluster named tutorial to use:


aws ecs create-cluster --cluster-name tutorial --region us-east-1

Output:

{
    "cluster": {
        "clusterArn": "arn:aws:ecs:region:aws_account_id:cluster/tutorial",
        "clusterName": "tutorial",
        "status": "ACTIVE",
        "registeredContainerInstancesCount": 0,
        "runningTasksCount": 0,
        "pendingTasksCount": 0,
        "activeServicesCount": 0,
        "statistics": []
    }
}

Register a task definition that is compatible with Fargate. It requires the use of the awsvpc network mode. The following is the example task definition used for this tutorial.

First, create a file named fargate-task.json with the contents of the following task definition:


{
    "family": "tutorial-task-def",
        "networkMode": "awsvpc",
        "containerDefinitions": [
            {
                "name": "sample-app",
                "image": "httpd:2.4",
                "portMappings": [
                    {
                        "containerPort": 80,
                        "hostPort": 80,
                        "protocol": "tcp"
                    }
                ],
                "essential": true,
                "entryPoint": [
                    "sh",
                    "-c"
                ],
                "command": [
                    "/bin/sh -c \"echo '<html> <head> <title>Amazon ECS Sample App</title> <style>body {margin-top: 40px; background-color: #333;} </style> </head><body> <div style=color:white;text-align:center> <h1>Amazon ECS Sample App</h1> <h2>Congratulations!</h2> <p>Your application is now running on a container in Amazon ECS.</p> </div></body></html>' >  /usr/local/apache2/htdocs/index.html && httpd-foreground\""
                ]
            }
        ],
        "requiresCompatibilities": [
            "FARGATE"
        ],
        "cpu": "256",
        "memory": "512"
}

Then, register the task definition using the fargate-task.json file that you created:


aws ecs register-task-definition --cli-input-json file://fargate-task.json --region us-east-1

Create a file named ecs-service-discovery.json with the contents of the ECS service that you are going to create. This example uses the task definition created in the previous step. An awsvpcConfiguration is required because the example task definition uses the awsvpc network mode.


{
    "cluster": "tutorial",
    "serviceName": "ecs-service-discovery",
    "taskDefinition": "tutorial-task-def",
    "serviceRegistries": [
       {
          "registryArn": "arn:aws:servicediscovery:region:aws_account_id:service/srv-utcrh6wavdkggqtk"
       }
    ],
    "launchType": "FARGATE",
    "platformVersion": "1.1.0",
    "networkConfiguration": {
       "awsvpcConfiguration": {
          "assignPublicIp": "ENABLED",
          "securityGroups": [ "sg-abcd1234" ],
          "subnets": [ "subnet-abcd1234" ]
       }
    },
    "desiredCount": 1
}

Create your ECS service, specifying the Fargate launch type and the 1.1.0 platform version, which uses service discovery:


aws ecs create-service --cli-input-json file://ecs-service-discovery.json --region us-east-1

Output:

{
    "service": {
        "serviceArn": "arn:aws:ecs:region:aws_account_id:service/ecs-service-discovery",
        "serviceName": "ecs-service-discovery",
        "clusterArn": "arn:aws:ecs:region:aws_account_id:cluster/tutorial",
        "loadBalancers": [],
        "serviceRegistries": [
            {
                "registryArn": "arn:aws:servicediscovery:region:aws_account_id:service/srv-utcrh6wavdkggqtk"
            }
        ],
        "status": "ACTIVE",
        "desiredCount": 1,
        "runningCount": 0,
        "pendingCount": 0,
        "launchType": "FARGATE",
        "platformVersion": "1.1.0",
        "taskDefinition": "arn:aws:ecs:region:aws_account_id:task-definition/tutorial-task-def:1",
        "deploymentConfiguration": {
            "maximumPercent": 200,
            "minimumHealthyPercent": 100
        },
        "deployments": [
            {
                "id": "ecs-svc/9223370516993140842",
                "status": "PRIMARY",
                "taskDefinition": "arn:aws:ecs:region:aws_account_id:task-definition/tutorial-task-def:1",
                "desiredCount": 1,
                "pendingCount": 0,
                "runningCount": 0,
                "createdAt": 1519861634.965,
                "updatedAt": 1519861634.965,
                "launchType": "FARGATE",
                "platformVersion": "1.1.0",
                "networkConfiguration": {
                    "awsvpcConfiguration": {
                        "subnets": [
                            "subnet-abcd1234"
                        ],
                        "securityGroups": [
                            "sg-abcd1234"
                        ],
                        "assignPublicIp": "ENABLED"
                    }
                }
            }
        ],
        "roleArn": "arn:aws:iam::aws_account_id:role/ECSServiceLinkedRole",
        "events": [],
        "createdAt": 1519861634.965,
        "placementConstraints": [],
        "placementStrategy": [],
        "networkConfiguration": {
            "awsvpcConfiguration": {
                "subnets": [
                    "subnet-abcd1234"
                ],
                "securityGroups": [
                    "sg-abcd1234"
                ],
                "assignPublicIp": "ENABLED"
            }
        }
    }
}

Step 3: Verify Service Discovery

You can verify that everything has been created properly by querying your service discovery information. After service discovery is configured, you can query it using either the AWS Cloud Map API operations or by using dig from within your VPC, as described below.

To verify service discovery configuration

Using the service discovery service ID, list the service discovery instances:


aws servicediscovery list-instances --service-id srv-utcrh6wavdkggqtk --region us-east-1

Output:

{
    "Instances": [
        {
            "Id": "16becc26-8558-4af1-9fbd-f81be062a266",
            "Attributes": {
                "AWS_INSTANCE_IPV4": "172.31.87.2"
                "AWS_INSTANCE_PORT": "80", 
                "AVAILABILITY_ZONE": "us-east-1a", 
                "REGION": "us-east-1", 
                "ECS_SERVICE_NAME": "ecs-service-discovery", 
                "ECS_CLUSTER_NAME": "tutorial", 
                "ECS_TASK_DEFINITION_FAMILY": "tutorial-task-def"
            }
        }
    ]
}

Using the service discovery namespace and service, use additional parameters to query the details about the service discovery instances:


aws servicediscovery discover-instances --namespace-name tutorial --service-name myapplication --query-parameters ECS_CLUSTER_NAME=tutorial

Output:

{
    "Instances": [
        {
            "InstanceId": "16becc26-8558-4af1-9fbd-f81be062a266", 
            "NamespaceName": "tutorial", 
            "ServiceName": "ecs-service-discovery", 
            "HealthStatus": "HEALTHY", 
            "Attributes": {
                "AWS_INSTANCE_IPV4": "172.31.87.2"
                "AWS_INSTANCE_PORT": "80", 
                "AVAILABILITY_ZONE": "us-east-1a", 
                "REGION": "us-east-1", 
                "ECS_SERVICE_NAME": "ecs-service-discovery", 
                "ECS_CLUSTER_NAME": "tutorial", 
                "ECS_TASK_DEFINITION_FAMILY": "tutorial-task-def"
            }
        }
    ]
}

The DNS records created in the Route 53 hosted zone for the service discovery service can be queried with the following AWS CLI commands.

Using the namespace ID, get information about the namespace, which includes the Route 53 hosted zone ID:


aws servicediscovery get-namespace --id ns-uejictsjen2i4eeg --region us-east-1

Output:

{
    "Namespace": {
        "Id": "ns-uejictsjen2i4eeg",
        "Arn": "arn:aws:servicediscovery:region:aws_account_id:namespace/ns-uejictsjen2i4eeg",
        "Name": "tutorial",
        "Type": "DNS_PRIVATE",
        "Properties": {
            "DnsProperties": {
                "HostedZoneId": "Z35JQ4ZFDRYPLV"
            }
        },
        "CreateDate": 1519777852.502,
        "CreatorRequestId": "9049a1d5-25e4-4115-8625-96dbda9a6093"
    }
}

Using the Route 53 hosted zone ID, get the resource record set for the hosted zone:


aws route53 list-resource-record-sets --hosted-zone-id Z35JQ4ZFDRYPLV --region us-east-1

Output:

{
    "ResourceRecordSets": [
        {
            "Name": "tutorial.",
            "Type": "NS",
            "TTL": 172800,
            "ResourceRecords": [
                {
                    "Value": "ns-1536.awsdns-00.co.uk."
                },
                {
                    "Value": "ns-0.awsdns-00.com."
                },
                {
                    "Value": "ns-1024.awsdns-00.org."
                },
                {
                    "Value": "ns-512.awsdns-00.net."
                }
            ]
        },
        {
            "Name": "tutorial.",
            "Type": "SOA",
            "TTL": 900,
            "ResourceRecords": [
                {
                    "Value": "ns-1536.awsdns-00.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400"
                }
            ]
        },
        {
            "Name": "myapplication.tutorial.",
            "Type": "A",
            "SetIdentifier": "16becc26-8558-4af1-9fbd-f81be062a266",
            "MultiValueAnswer": true,
            "TTL": 300,
            "ResourceRecords": [
                {
                    "Value": "172.31.87.2"
                }
            ]
        }
    ]
}

You can also query the DNS using dig from an instance within your VPC with the following command:
```
dig +short myapplication.tutorial
```
Output:
```
172.31.87.2
```

Step 4: Clean Up

When you are finished with this tutorial, you should clean up the associated resources to avoid incurring charges for unused resources.

To clean up the service discovery instances and Amazon ECS resources

Deregister the service discovery service instances:


aws servicediscovery deregister-instance --service-id srv-utcrh6wavdkggqtk --instance-id 16becc26-8558-4af1-9fbd-f81be062a266 --region us-east-1

Output:

{
    "OperationId": "xhu73bsertlyffhm3faqi7kumsmx274n-jh0zimzv"
}

Using the OperationId from the previous output, verify that the service discovery service instances were deregistered successfully:


aws servicediscovery get-operation --operation-id xhu73bsertlyffhm3faqi7kumsmx274n-jh0zimzv --region us-east-1

Output:

{
    "Operation": {
        "Id": "xhu73bsertlyffhm3faqi7kumsmx274n-jh0zimzv",
        "Type": "DEREGISTER_INSTANCE",
        "Status": "SUCCESS",
        "CreateDate": 1525984073.707,
        "UpdateDate": 1525984076.426,
        "Targets": {
            "INSTANCE": "16becc26-8558-4af1-9fbd-f81be062a266",
            "ROUTE_53_CHANGE_ID": "C5NSRG1J4I1FH",
            "SERVICE": "srv-utcrh6wavdkggqtk"
        }
    }
}

Delete the service discovery service:


aws servicediscovery delete-service --id srv-utcrh6wavdkggqtk --region us-east-1

Delete the service discovery namespace:


aws servicediscovery delete-namespace --id ns-uejictsjen2i4eeg --region us-east-1

Output:

{
    "OperationId": "c3ncqglftesw4ibgj5baz6ktaoh6cg4t-jh0ztysj"
}

Using the OperationId from the previous output, verify that the service discovery namespace was deleted successfully:


aws servicediscovery get-operation --operation-id c3ncqglftesw4ibgj5baz6ktaoh6cg4t-jh0ztysj --region us-east-1

Output:

{
    "Operation": {
        "Id": "c3ncqglftesw4ibgj5baz6ktaoh6cg4t-jh0ztysj",
        "Type": "DELETE_NAMESPACE",
        "Status": "SUCCESS",
        "CreateDate": 1525984602.211,
        "UpdateDate": 1525984602.558,
        "Targets": {
            "NAMESPACE": "ns-rymlehshst7hhukh",
            "ROUTE_53_CHANGE_ID": "CJP2A2M86XW3O"
        }
    }
}

Update the Amazon ECS service so that the desired count is 0, which allows you to delete it:


aws ecs update-service --cluster tutorial --service ecs-service-discovery --desired-count 0 --force-new-deployment --region us-east-1

Delete the Amazon ECS service:


aws ecs delete-service --cluster tutorial --service ecs-service-discovery --region us-east-1

Delete the Amazon ECS cluster:


aws ecs delete-cluster --cluster tutorial --region us-east-1

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