Docker uses four ways to identify images: mirror ID, mirror name, mirror tag, and summary. The mirror ID is unique and immutable, the mirror name is readable and usually consists of a repository name and a mirror name, and the mirror tag is used to identify a specific version or variant, and the summary is based on the mirror content rather than metadata.
How Docker identifies mirroring
Docker uses the following four ways to identify images:
1. Mirror ID
- A unique and immutable alphanumeric string.
- Represents a specific version of the image.
- View through the
docker images
command.
2. Mirror name
- A readable name, usually consisting of a repository name and a mirror name.
- For example: "nginx" or "library/nginx".
- If the version is not specified, the latest version is used.
3. Mirror tags
- User-defined tags that identify specific versions or variants of the image.
- For example: "latest" or "1.17".
- Specified by
docker pull IMAGE_NAME:TAG
command.
4. Summary
- A unique identifier similar to a mirror ID, but based on the content of the image instead of metadata.
- View via
docker inspect IMAGE_NAME | grep -i digest
command.
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