このエラーメッセージに関する原因と対処に関して説明します。
エラーメッセージ(英語)：
ecs unable to create task definition
対処
関連リンク
Amazon ECS error: cannot create a task definition with no ...
https://stackoverflow.com/questions/43780904/amazon-ecs-error-cannot-create-a-task-definition-with-n・・・
Best Practice for Updating AWS ECS Service Tasks
https://stackoverflow.com/questions/46018883/best-practice-for-updating-aws-ecs-service-tasks
Useless Amazon ECS Error Message when creating tasks
https://stackoverflow.com/questions/45173637/useless-amazon-ecs-error-message-when-creating-tasks
AWS ECS - What is the difference between a task and a ...
https://stackoverflow.com/questions/42960678/aws-ecs-what-is-the-difference-between-a-task-and-a-ser・・・
Linking containers between task definitions in AWS ECS?
https://stackoverflow.com/questions/34517265/linking-containers-between-task-definitions-in-aws-ecs
Creating a Task Definition - Amazon Elastic Container Service - AWS ...
https://docs.aws.amazon.com/AmazonECS/latest/developerguide/create-task-definition.html
Tutorial: Creating a Cluster with a Fargate Task Using the AWS CLI ...
https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ECS_AWSCLI_Fargate.html
RegisterTaskDefinition - Amazon EC2 Container Service
https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_RegisterTaskDefinition.html
FARGATE: Error when trying to create task definition from docker ...
https://github.com/aws/amazon-ecs-cli/issues/463
Gentle Introduction to How AWS ECS Works with Example Tutorial
https://medium.com/boltops/gentle-introduction-to-how-aws-ecs-works-with-example-tutorial-cea3d27ce6・・・