OTEL communication is failing in AWS fargate

[Srianands]

I am trying to set up Datadog monitoring for my app via public.ecr.aws/aws-observability/aws-otel-collector:latest collector image image.

 {
      "name": "otel-collector",
      "image": "public.ecr.aws/aws-observability/aws-otel-collector:latest",
      "cpu": 128,
      "memoryReservation": 256,
      "essential": false,
      "portMappings": [
        {
          "containerPort": 4317,
          "hostPort": 4317,
          "protocol": "tcp"
        }
      ],
      "secrets": [
    {
      "name": "AOT_CONFIG_CONTENT",
      "valueFrom": "aws-account:parameter/dev/otel-cofig"
    }
  ],
      "logConfiguration": {
        "logDriver": "awslogs",
        "options": {
          "awslogs-group": "/ecs/otel-collector-agent",
          "awslogs-create-group": "true",
          "awslogs-region": "REPLACE_WITH_AWS_REGION",
          "awslogs-stream-prefix": "ecs"
        }
      }
    } 

I have an app running as another image in Fargate with environment variables as

{
          "name": "OTEL_EXPORTER_OTLP_ENDPOINT",
          "value": "http://localhost:4317"
        },
        {
          "name": "OTEL_RESOURCE_ATTRIBUTES",
          "value": "service.namespace=TC,service.name=issue-management"
        },
        {
          "name": "OTEL_METRICS_EXPORTER",
          "value": "none"
        }

But after deployment while checking the logs I could see the failures as
[otel.javaagent 2025-05-12 11:52:49:306 +0000] [OkHttp http://localhost:4317/...] ERROR io.opentelemetry.exporter.internal.http.HttpExporter - Failed to export spans. The request could not be executed. Full error message: Connection reset
2025-05-12 11:52:49.306,java.net.SocketException: Connection reset
2025-05-12 11:52:49.306, at java.base/sun.nio.ch.NioSocketImpl.implRead(NioSocketImpl.java:318)
2025-05-12 11:52:49.306, at java.base/sun.nio.ch.NioSocketImpl.read(NioSocketImpl.java:346)
2025-05-12 11:52:49.306, at java.base/sun.nio.ch.NioSocketImpl$1.read(NioSocketImpl.java:796)

Please help with this issue. I have tried locally using Docker it was working well.

[laurit]

port 4317 that you are using in OTEL_EXPORTER_OTLP_ENDPOINT is the default port for OTLP/gRPC but the agent defaults to OTLP/HTTP which by default uses port 4318. Either change the port or configure the agent to use grpc.

[Srianands]

I have added this env
{
"name": "OTEL_EXPORTER_OTLP_PROTOCOL",
"value": "grpc"
}, is that okay or need to updated the port?