Image pulls for the runtimes that launch containers: ECS (and Batch
through it) and Lambda PackageType=Image functions pull on every launch
with pull_image; EC2 instances and CodeBuild builds, whose images
stand in for an AMI or a curated build image, pull only when the image is
missing with ensure_image.
Naming and lifecycle of the named container volumes that keep a
container-backed resource’s data (an RDS database, an ElastiCache RDB, an
EC2 instance’s data dir) across a container being recreated.