DVA-C02 Troubleshooting and Optimization Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  The task definition family name is incorrect.

  Why it's wrong here

  An incorrect task definition family name would prevent the ECS service or task from finding and launching the specified task definition revision in the first place. However, it does not directly cause an image pull error, which occurs later in the task lifecycle when the container runtime attempts to download the image specified within a successfully identified task definition. The family name primarily serves as an identifier for a collection of task definition revisions.

• ✓

  The task execution role lacks permissions to pull from ECR.

  Why this is correct

  The task execution role is critical for allowing the Amazon ECS agent to perform necessary actions on your behalf, including pulling container images from private repositories like Amazon ECR. If this role lacks specific permissions such as `ecr:GetDownloadUrlForLayer`, `ecr:BatchGetImage`, and `ecr:BatchCheckLayerAvailability`, the ECS agent will be unauthorized to retrieve the image layers. Consequently, the container runtime will fail to download the image, resulting in a distinct image pull error.

• ✗

  The container port is not mapped to a host port.

  Why it's wrong here

  Port mapping defines how network traffic is routed to a container after it has successfully started and is running. An image pull error, conversely, occurs much earlier in the task provisioning process, specifically when the container runtime attempts to download the container image from its repository. Therefore, issues with port mapping, or its absence, do not affect the ability to pull the image itself, only how the application inside the container might be accessed later.

• ✗

  The CPU or memory limits are too low for the container.

  Why it's wrong here

  CPU or memory limits are resource constraints applied to a container once it attempts to start after its image has been successfully pulled. If these limits are set too low, the container might fail to start, crash during execution, or experience performance issues due to resource starvation. However, the act of pulling the container image from the repository precedes the enforcement of these resource limits, meaning insufficient CPU or memory would not manifest as an image pull failure.

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