diff --git a/docs/glossary.md b/docs/glossary.md index 95c8ec9e..6f07a190 100644 --- a/docs/glossary.md +++ b/docs/glossary.md @@ -1,43 +1,70 @@ + + # Glossary -This page contains distribution related terms. For a complete Docker glossary, -see the [glossary in the full documentation set](http://docs.docker.com/reference/glossary/). +This page contains definitions for distribution related terms.
-
Blob
+

Blob

- The primary unit of registry storage. A string of bytes identified by - content-address, known as a _digest_. +
A blob is any kind of content that is stored by a Registry under a content-addressable identifier (a "digest").
+

+ Layers are a good example of "blobs". +

-
Image
-
An image is a collection of content from which a docker container can be created.
- -
Layer
+

Image

- A tar file representing the partial content of a filesystem. Several - layers can be "stacked" to make up the root filesystem. +
An image is a named set of immutable data from which a Docker container can be created.
+

+ An image is represented by a json file called a manifest, and is conceptually a set of layers. + + Image names indicate the location where they can be pulled from and pushed to, as they usually start with a registry domain name and port. + +

+
+ +

Layer

+
+
A layer is a tar archive bundling partial content from a filesystem.
+

+ Layers from an image are usually extracted in order on top of each other to make up a root filesystem from which containers run out. +

-
Manifest
-
Describes a collection layers that make up an image.
+

Manifest

+
A manifest is the JSON representation of an image.
-
Registry
-
A registry is a service which serves repositories.
- -
Repository
-
- A repository is a collection of docker images, made up of manifests, tags - and layers. The base unit of these components are blobs. +

Namespace

+
A namespace is a collection of repositories with a common name prefix.
+

+ The namespace with an empty prefix is considered the Global Namespace. +

-
Tag
-
Tag provides a common name to an image.
+

Registry

+
A registry is a service that let you store and deliver images.
+
-
Namespace
-
A namespace is a collection of repositories with a common name prefix. The - namespace with an empty common prefix is considered the Global Namespace.
+

Repository

+
+
A repository is a set of data containing all versions of a given image.
+
+ +

Scope

+
A scope is the portion of a namespace onto which a given authorization token is granted.
+ +

Tag

+
A tag is conceptually a "version" of a named image.
+

+ Example: `docker pull myimage:latest` instructs docker to pull the image "myimage" in version "latest". +

+ +
+ -
Scope
-
A common repository name prefix.