ImagePullBehavior

The behavior used to customize the Docker image pull process on container instances. See ECS_IMAGE_PULL_BEHAVIOR in the AWS docs.

| Default value | default | | Allowed values | default, always, once, prefer-cached |

Use Cases

• Setting to always to guarantee that the latest image version is pulled on every task launch
• Setting to prefer-cached to speed up container startup times by reusing locally cached images
• Setting to once to pull an image only once per instance, reducing ECR bandwidth and API calls

Additional Information

• default -- The ECS agent uses Docker's default image pull behavior, which typically pulls the image if it is not already cached locally.
• always -- The image is always pulled from the registry, even if a cached version exists. This is useful when you want to ensure the latest image tag is always used.
• once -- The image is only pulled once per instance. Subsequent tasks reuse the cached image, even if the tag has been updated in the registry.
• prefer-cached -- The cached image is used if available. If no cached image exists, the image is pulled from the registry. This is the fastest option for startup time.

$ convox rack params set ImagePullBehavior=always

See Also

• InstanceType
• InstanceCount