Task Definition- It is a collection of 1 or more container configurations. Some Tasks may need only one container, while other Tasks may need 2 or more potentially linked containers running concurrently.

Task — This is a running container with the settings defined in the Task Definition. It can be thought of as an “instance” of a Task Definition.

Service- It is used to guarantee that you always have some number of Tasks running at all times. If a Task's container exits due to an error, or the underlying EC2 instance fails and is replaced, the ECS Service will replace the failed Task.

for more information you can visit this website stackoverflow.com/questions/42960678/what-is-the-…

Hope this helpes you Qasimuddin Farhan Mohammed

Sayali Jadhav thanks for the explanation. I have always struggled to understand this concept in ECS.