About Version Numbers¶
This page explains the structure of version numbers and how version numbers are mapped to Docker container tags of images.
Syntax of Container Image Version Numbers¶
The full version number of a sedex Client container image consists of two composite version numbers of the contained components, as shown in the following table:
| Component | Version number |
|---|---|
| full version number of a container image | 7.0.4_container-1.1.0 |
| version of the sedex Client contained in the container | 7.0.4 |
| version of the container logic | container-1.1.0 |
Version numbers are based on Semantic Versioning
The version numbers of the two components sedex Client and Docker Container Logic follow the principle of Semantic Versioning (see semver.org).
Summary: Given a version number MAJOR.MINOR.PATCH, increment the:
- MAJOR version when you make incompatible changes,
- MINOR version when you add functionality in a backwards compatible manner, and
- PATCH version when you make backwards compatible bug fixes.
Tags of an Image published on Docker Hub¶
Each sedex container image on Docker Hub is tagged with multiple tags representing the different version numbers:
| Tag | Meaning of the Tag | Uniqueness |
|---|---|---|
7.0.4_container-1.1.0 |
The full version tag references the sedex container image with the specific client version and the specific container version. | This tag is unique and references a specific container image throughout its lifetime. |
7.0.4 |
The sedex Client version tag references the most current sedex container image containing the specific client version. | This tag is not unique and references several container images for a specific sedex Client software version over the entire lifetime. Whenever an improved container will be released for this sedex Client version, the tag will be pointing to this new version. |
container-1 |
The major container version tag references the most current sedex container image of this MAJOR version. | This tag is not unique and may reference multiple container images for a specific MAJOR container version over the whole lifetime. Whenever an enhanced container is released with this MAJOR version number, the tag points to this latest image. You can assume that the images in this series will continue to be developed in a compatible manner. |
container-1.1 |
The MAJOR.MINOR container version tag references the latest PATCH level of the sedex container MAJOR.MINOR version. | This tag is not unique and may reference multiple PATCH levels of the container image over time. Whenever a new PATCH level of this MAJOR.MINOR version is released, the tag points to this latest image. You can assume that the images in this series will continue to be developed in a compatible manner. |
Why does the tag latest not exist?
In the Docker world the special tag latest usually references the most recent image for a container.
It can be dangerous to use this tag because it refers to different versions of the container over time that may not be compatible.
Using the latest tag can lead to unpredictable behavior.
For this reason, sedex avoids using the latest tag.