Private Registries

Definition

A highly secure, access-controlled repository for storing Docker images, preventing the general public from downloading a company's proprietary source code.

Explain Like I'm New

A private App Store just for your company. You don't put your company's secret banking app on the public internet. You put it in a locked vault that only your servers have the key to.

Real World Example

AWS Elastic Container Registry (ECR) or Google Artifact Registry. A developer builds a new version of the company website and pushes it to ECR. The production server uses an IAM token to securely pull the image and deploy it.

Common Use Cases

•Enterprise security
•Proprietary code storage

Interview Questions

basic

Can anyone on the internet pull an image from a Private Registry?

intermediate

If you push an image without specifying a registry URL (e.g., `docker push my-app`), where does Docker attempt to push it by default?

Flash Cards

Question

Public pull?

Click to reveal answer

Answer

No. It requires secure authentication (username/password or IAM tokens).

Question

Default push location?

Click to reveal answer

Answer

Docker Hub. If you don't explicitly prepend your private registry URL (e.g., `docker push 12345.dkr.ecr.aws.com/my-app`), Docker assumes you want to push to the public Docker Hub.