AWS service can't start task, but starting task manually works - amazon-web-services

Question

Until now I had a backend running single tasks. I now want to switch to services starting my tasks. For two of the tasks I need direct access to them so I tried using ServiceConnect.
When I run this task standalone it starts. When I start a service without ServiceConnect with the same task inside it also starts. When I enable ServiceConnect I get this error message inside of the 'Deployments and events' tab in the service:
service (...) was unable to place a task because no container instance met all of its requirements.
The closest matching container-instance (...) is missing an attribute required by your task.
For more information, see the Troubleshooting section of the Amazon ECS Developer Guide.
When I check the attributes of all free containers with:
ecs-cli check-attributes --task-def some-task-definition --container-instances ... --cluster some-cluster
I just get:
Container Instance Missing Attributes
heyvie-backend-dev None
My task definition looks like that:
{
"family": "some-task-definition",
"taskRoleArn": "arn:aws:iam::...:role/ecsTaskExecutionRole",
"executionRoleArn": "arn:aws:iam::...:role/ecsTaskExecutionRole",
"networkMode": "awsvpc",
"cpu": "1024",
"memory": "982",
"containerDefinitions": [
{
"name": "...",
"image": "...",
"essential": true,
"healthCheck": {
"command": ["..."],
"startPeriod": 20,
"retries": 3
},
"portMappings": [
{
"name": "somePortName",
"containerPort": 4321
}
],
"mountPoints": [
{
"sourceVolume": "...",
"containerPath": "..."
}
],
"logConfiguration": {
"logDriver": "awslogs",
"options": {
"awslogs-group": "...",
"awslogs-region": "eu-...",
"awslogs-stream-prefix": "..."
}
}
}
],
"volumes": [
{
"name": "...",
"efsVolumeConfiguration": {
"fileSystemId": "...",
"rootDirectory": "/",
"transitEncryption": "ENABLED"
}
}
],
"requiresCompatibilities": ["EC2"]
}
My service definition looks like that:
{
"cluster": "some-cluster",
"serviceName": "...",
"taskDefinition": "some-task-definition",
"desiredCount": 1,
"launchType": "EC2",
"deploymentConfiguration": {
"maximumPercent": 100,
"minimumHealthyPercent": 0
},
"placementConstraints": [
{
"type": "distinctInstance"
}
],
"networkConfiguration": {
"awsvpcConfiguration": {
"subnets": [
...
],
"securityGroups": ["..."],
"assignPublicIp": "DISABLED"
}
},
"serviceConnectConfiguration": {
"enabled": true,
"namespace": "someNamespace",
"services": [
{
"portName": "somePortName",
"clientAliases": [
{
"port": 4321
}
]
}
]
},
"schedulingStrategy": "REPLICA",
"enableECSManagedTags": true,
"propagateTags": "SERVICE"
}
I also added this to the user data of my launch template:
#!/bin/bash
cat <<'EOF' >> /etc/ecs/ecs.config
ECS_ENABLE_TASK_IAM_ROLE=true
ECS_CLUSTER=some-cluster
EOF
Did anyone experience something similiar or does know what could cause that issue?

Answer 1

I used ServiceDiscovery, I think, it's the easiest way to replace a dynamic ip address of a task in a service (on every restart the ip address changes and that's probably what you're trying to avoid?).
With ServiceDiscovery you are creating a new DNS record and instead of ip-address:port you can just use serviceNameOfNamespace.namespace. to connect to a task. ServiceDiscovery worked without any problem on an existing task.
Hope that helps, I don't really know if there are any benefits for ServiceConnect except for higher connection counts and retry functionalities, so if anybody knows more about differences between those I'm happy to learn.