<strong>A big retail company A has various web/non-web services to support its routine companywide operations. The applications are using various EC2 instance types such as Amazon Linux EC2, Ubuntu EC2 and Windows Server 2016. There are also several on-premise linux Redhat servers. The DevOps team has used AWS service for 3 years and is considering to explore ECS service on these applications. </strong>

Answer options:

A.For Amazon Linux and Ubuntu EC2 instances, the ECS agent can be installed using a package. However for Windows Server EC2 and on-premise Redhat server, unfortunately the ECS agent cannot be installed since the agent only works on linux.
B.All the AWS EC2 instances and on-premise Redhat servers can install the ECS agent. The ECS agent is open sourced in Github and has detailed instructions.
C.For EC2 instances including Amazon Linux, Ubuntu and Windows, the ECS agent can be installed. However for on-premise Redhat server, unfortunately the ECS agent cannot be installed since Amazon ECS container agent is only supported on Amazon EC2 instances.
D.Only Amazon ECS-optimized AMIs can use ECS agent and have that agent installed. Unless those EC2 instances can be replaced with ECS-optimized AMIs, they cannot use ECS services since there is no way to install ECS agent.

Correct Answer – C
The Amazon ECS container agent allows container instances to connect to your cluster. The Amazon ECS container agent is included in the Amazon ECS-optimized AMIs, but you can also install it on any Amazon EC2 instance that supports the Amazon ECS specification.
One thing to note is that the Amazon ECS container agent is only supported on Amazon EC2 instances. The source code for the Amazon ECS container agent is available on GitHub. It has listed the details on how to install/configure agent in linux and windows.
Some details also refer to https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ECS_agent.html.
Option A is incorrect because Windows EC2 instance can install the agent as well.
Option B is incorrect because on-premise instances cannot install the agent. The ECS service only works for EC2 instances.
Option D is incorrect because although it is true that the Amazon ECS container agent is included in the Amazon ECS-optimized AMIs, you can also install it on other EC2 instances.