What is a container registry, and what are examples?
Options
- A place to store and share container images, like Docker Hub or ECR (Correct option)
- A list of the containers that are running on a host machine
- A firewall that filters the traffic going to the containers
- A source code repository that stores the Dockerfiles
Answer
A place to store and distribute container images: Docker Hub, AWS ECR, Azure Container Registry (ACR), GitHub Container Registry
Why
After docker build the image exists only on your machine. You docker push it to a registry so servers and Kubernetes can pull it.
Public: Docker Hub. Private cloud registries: AWS ECR, Azure ACR, Google Artifact Registry, GitHub Container Registry.
Images are identified as registry/name:tag. Prefer specific tags (1.4.2) over latest, so deployments are reproducible.
Remember
Registry = shared storage for images (push/pull).