centos/systemd: provide stable tags to released versions

[rhcarvalho]

Currently the only tag for https://hub.docker.com/r/centos/systemd/ is :latest. For people depending on this base image, it is considered good practice to depend on a stable version / tag.

E.g., it should be possible to write:

FROM centos/systemd:7
...

That would ensure that the image is always build from a version of CentOS 7, and not CentOS 8 or anything else that might become :latest.

[antoinetran]

I can also add that it would be best to mirror the tag list of centos here. It is good to inherit from centos/systemd:7, it is even better to inherit from centos/systemd:7.3.116 for ex.

[gzeronet]

👍

[rgarrigue]

👍 too

[hswong3i]

Recently some of my Travis CI build on centos/systemd:latest failed due to CentOS 7.4 released, where centos/systemd:latest is not yet update and still pointing to CentOS 7.3 version, causing yum -y update timeout with following error message:

No output has been received in the last 10m0s, this potentially indicates a stalled build or something wrong with the build itself.

This could only be fixed if:

• We manually run command as mentioned in https://hub.docker.com/r/centos/systemd/~/dockerfile/ during .travis.yml before_install section, or
• centos/systemd:latest updated and point to latest centos:7.4, or
• centos/systemd could provide tags as sync with centos as mentioned in centos/systemd: provide stable tags to released versions #124