Where images live.
WHAT A REGISTRY IS
A service storing and serving images.
WHAT THE OPTIONS ARE
Public registries Registries from cloud providers A registry you run yourself
WHAT TO CONSIDER
Cost, including transfer Where it is located, for pull speed Access control Whether it scans images
WHY LOCATION MATTERS LOCALLY
Pulling large images across distance is slow and consumes data.
WHAT TO DO ABOUT IT
Keep images small, and consider a local mirror.
WHAT A TAG IS FOR
A readable reference.
WHAT TAGGING SCHEME TO USE
A version, and the commit identifier.
WHY THE COMMIT IDENTIFIER
It ties a running image to exact source, unambiguously.
WHAT TO NEVER DEPLOY
A moving tag.
WHY
You cannot know what is running or reproduce it.
WHAT TO USE FOR CERTAINTY
The digest.
WHAT AUTHENTICATION REGISTRIES USE
Credentials or tokens, configured on each host.
WHAT TO BE CAREFUL WITH
Credentials stored unencrypted on hosts Public images from unknown publishers
WHAT TO PREFER
Official images, or ones you build yourself.
WHAT TO IMPLEMENT
Retention, removing old images.
WHY
Registry storage grows continuously and costs money.
