ECR Task definition: Container links should not have a cycle? - amazon-web-services

Question

I'm using AWS-CLI to register an ECR task definition. My task definition is like follows:
{
"family": "",
"taskRoleArn": "",
"executionRoleArn": "",
"networkMode": "none",
"containerDefinitions": [
{
"name": "",
"image": "",
"cpu": 0,
"memory": 0,
"memoryReservation": 0,
"links": [
""
],
"portMappings": [
{
"hostPort": 80,
"protocol": "tcp",
"containerPort": 80
}
],
"essential": true,
"entryPoint": [
""
],
"command": [
""
],
"environment": [
{
"name": "",
"value": ""
}
],
"mountPoints": [
{
"sourceVolume": "",
"containerPath": "",
"readOnly": true
}
],
"volumesFrom": [
{
"sourceContainer": "",
"readOnly": true
}
],
"linuxParameters": {
"capabilities": {
"add": [
""
],
"drop": [
""
]
},
"devices": [
{
"hostPath": "",
"containerPath": "",
"permissions": [
"mknod"
]
}
],
"initProcessEnabled": true
},
"hostname": "",
"user": "",
"workingDirectory": "",
"disableNetworking": true,
"privileged": true,
"readonlyRootFilesystem": true,
"dnsServers": [
""
],
"dnsSearchDomains": [
""
],
"extraHosts": [
{
"hostname": "",
"ipAddress": ""
}
],
"dockerSecurityOptions": [
""
],
"dockerLabels": {
"KeyName": ""
},
"ulimits": [
{
"name": "fsize",
"softLimit": 0,
"hardLimit": 0
}
],
"logConfiguration": {
"logDriver": "syslog",
"options": {
"KeyName": ""
}
}
}
],
"volumes": [
{
"name": "",
"host": {
"sourcePath": ""
}
}
],
"placementConstraints": [
{
"type": "memberOf",
"expression": ""
}
],
"requiresCompatibilities": [
"EC2"
],
"cpu": "10",
"memory": "600"
}
, which is basically almost identical to the auto-generated skeleton:
aws ecs register-task-definition --generate-cli-skeleton
But it looks that when using the command
aws ecs register-task-definition --family taskDef --cli-input-json taskDef-v1.json --region us-east-2
I get this:
An error occurred (ClientException) when calling the RegisterTaskDefinition operation: Container links should not have a cycle
What am I doing wrong?

Answer 1

That particular error is caused because you have empty links defined:
"links": [
""
]
The CLI skeleton is a template you need to edit - it has many empty values for fields that are not required. The minimum task definition template is something like:
{
"containerDefinitions": [
{
"name": "my-task-name",
"image": "my-registry/my-image",
"memoryReservation": 256,
"cpu": 256
}
]
}