An image tag is a label after an image name that selects a particular container image version or variant. For example, redis:alpine selects the Alpine-based Redis image. section 2.1.3
Use tags to distinguish images sharing the same repository name:
- latest is the special default tag. Omitting a tag, as in redis, makes Docker interpret the reference as redis:latest. section 2.1.3
- Version tags identify a release, such as 7.4.1. Variant tags can combine a release with its base image, such as 7.4.1-alpine or 7.4.1-bookworm. section 2.1.3
- A tag can select different underlying environments: Alpine is stripped down, while Bookworm is based on Debian. section 2.1.3
Selecting Redis images
Run redis:alpine for the Alpine variant, or use redis:7.4.1-alpine to request a specific Redis version and variant. Docker pulls the image when it is not already cached locally; later runs use the cached image. section 2.1.3
