I’m new guy in AWS Amazone ecosystem. I want to deploy 2 services. First one is Spring-Boot application and second one will contain Mongodb. Spring microservice contains Mongock, which is up when application is started and it performs migrations to database. I want to do a simple deploy, using ECS. What I did first:

• created fargate cluster in order to create and start services in ecs there.
• built mongo image, pushed to ECR repo, built Task definition, depoyed Service with minimum 1 task. Ok, database was setup.
• then I copied mongo task public ip, set it as host to spring application properties, built spring image, pushed to ECR, started Service and task.

On this moment all worked fine – mongock connected to mongo service and applied migrations. As we know every task has dynamic ip, and I dont plan to have running tasks non-stop. After googling I found solution – Service Connect and decided to give DNS-names, in order task agent could find where to push requests.
For mongodb service I pushed next config using aws cli:

{
  "enabled": true,
  "namespace": "test",
  "services": [
    {
      "portName": "27017mongo",
      "discoveryName": "user-mongo",
      "clientAliases": [
        {
          "port": 27017
        }
      ]
    }
  ]
}

After that I checked service-described:

serviceConnectConfiguration": {
                    "enabled": true,
                    "namespace": "arn:aws:servicediscovery:eu-north-1:891377330754:namespace/ns-p76w3mzvv5py466a",
                    "services": [
                        {
                            "portName": "27017mongo",
                            "discoveryName": "user-mongo",
                            "clientAliases": [
                                {
                                    "port": 27017,
                                    "dnsName": "user-mongo.test"
                                }
                            ]
                        }
                    ]
                },
                "serviceConnectResources": [
                    {
                        "discoveryName": "user-mongo",
                        "discoveryArn": "arn:aws:servicediscovery:eu-north-1:891377330754:service/srv-rqiink64a7izgkdy"
                    }
                ]
            },

From what I see, DNS name was registered normally. In service appeared new task container ecs-service-connect in pair with user-mongo container.

I went next. Set hostname to spring props:

  data:
    mongodb:
      uri: mongodb://user-mongo.test:27017/iAutoService02

      auto-index-creation: true
      database: iAutoService02
      port: 27017
      host: user-mongo.test

After that I deployed service and uploaded connect config:

{
  "enabled": true,
  "namespace": "test",
  "services": [
    {
      "portName": "8083user",
      "discoveryName": "user-service",
      "clientAliases": [
        {
          "port": 8083
        }
      ]
    }
  ]
}

So both services are in ‘test’ cluster namespace. Spring service was updated, ecs-service-connect appeared too. And I considered things done, but suddenly Spring task fell down. I checked the logs:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'getBuilder' defined in io.mongock.runner.springboot.config.MongockContext: Unsatisfied dependency expressed through method 'getBuilder' parameter 0: Error creating bean with name 'connectionDriver' defined in class path resource [io/mongock/driver/mongodb/springdata/v4/config/SpringDataMongoV4Context.class]: Failed to instantiate [io.mongock.driver.api.driver.ConnectionDriver]: Factory method 'connectionDriver' threw exception with message: Timed out after 30000 ms while waiting to connect. Client view of cluster state is {type=UNKNOWN, servers=[{address=user-mongo.test:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketException: user-mongo.test}, caused by {java.net.UnknownHostException: user-mongo.test}}]

From what I see – Service cannot connect to database, because can not resolve

user-mongo.test

host. Unfortunately, I didnt find any solution. What I’m doing wrong? how to make my aws task to see each other?