Why does docker use tags?

In docker, because tags can be used to mark local processes and classify them into a certain warehouse, the tag command needs to be used; the syntax of the tag command is "docker tag SOURCE_IMAGE[:TAG] original image TARGET_IMAGE[ :TAG] New Image".

The operating environment of this tutorial: linux7.3 system, docker version 19.03, Dell G3 computer.

Why does docker use tag

docker tag: Mark the local image and classify it into a certain warehouse.

Syntax

docker tag [OPTIONS] IMAGE[:TAG] [REGISTRYHOST/][USERNAME/]NAME[:TAG]

Example

Mark the image ubuntu:15.10 as a runoob/ubuntu:v3 image.

The example is as follows:

1. docker images view the image

docker images

2. Tag the docker.io/centos image. Before labeling, the label of docker.io/centos defaults to latest. If it is another version, please indicate it.
For example, tag the docker.io/centos image:

docker tag docker.io/centos docker.io/centos:v1

After the execution is completed, check the new image through docker images TAG: v1
Success!

3. By analogy, when you need to develop a second version, continue to tag: v2

docker tag docker.io/centos docker.io/centos:v2

4. If for some reason, when you want When you need to roll back the version, you can create a container by specifying the label's image:

Chestnut:

Start centos:v1 version:

docker run-itd docker.io/centos:v1

After execution, view through docker ps

Found that the container has been started!

Recommended learning: "docker video tutorial"

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