Fix: convert deprecated labels to annotations

[ghost]

Patch converts deprecated[0] labels to annotations conformant to OCI
image specifications[1].

[0] - https://github.com/label-schema/label-schema.org#label-schemaorg
[1] - https://github.com/opencontainers/image-spec/blob/master/annotations.md#annotations

Cc: @bobcanthelpyou @remy-tiitre @dgoo2308 @jperrin

[centos-ci]

Can one of the admins verify this patch?

[ghost]

Hello Jim @jperrin and @Habbie Peter,
Please, review this PR. Thank you!

[dgoo2308]

Nice work,

but it's missing the org.opencontainers.image.ref.name

with:

RELEASEVER="${KSNAME:7:1}"
ARCH="${KSNAME:8}"
[ -n "${ARCH}" ] && ARCHD="-${ARCH}"

I suggest something in the likes of centos-${RELEASEVER}${ARCHD}-${BUILDATE}, which would result in e.g. :

org.opencontainers.image.ref.name=centos-6-i386-20181201

or for x86_64 CentOS 6:

org.opencontainers.image.ref.name=centos-6-20181201

and would it be nice to extent the title with release and arch CentOS ${RELEASEVER} Base Image ${ARCH} , which would result in e.g. :

org.opencontainers.image.title="CentOS 7 Base Image arm64"

or for x86_64

org.opencontainers.image.title="CentOS 7 Base Image"

while having the description a bit more descriptive, with text from docs repo's :

org.opencontainers.image.description="CentOS ${RELEASEVER} Base Image${ARCH}. CentOS 
Linux is a community-supported distribution derived from sources freely provided to the 
public by Red Hat for Red Hat Enterprise Linux (RHEL). As such, CentOS Linux aims to be 
functionally compatible with RHEL. The CentOS Project mainly changes packages to remove 
upstream vendor branding and artwork. CentOS Linux is no-cost and free to redistribute. Each 
CentOS Linux version is maintained for up to 10 years (by means of security updates -- the 
duration of the support interval by Red Hat has varied over time with respect to Sources 
released). A new CentOS Linux version is released approximately every 2 years and each 
CentOS Linux version is periodically updated (roughly every 6 months) to support newer 
hardware. This results in a secure, low-maintenance, reliable, predictable, and reproducible 
Linux environment"

[dgoo2308]

As for:

org.opencontainers.image.source, it should point to this repository as this is the source that creates the image, thus:

org.opencontainers.image.source="https://github.com/CentOS/sig-cloud-instance-build.git"

and the other missing item org.opencontainers.image.revision:

with, e.g.:

COMMIT="$(git describe --always )"

we can set:

org.opencontainers.image.revision="${COMMIT}"

this will, in combination with org.opencontainers.image.source, to trace back to the source commit that produced this image.

PS: I don't known if during the build the commit or git is available.

[ghost]

Hello, Danny (@dgoo2308). Thank you for your comments and sorry for late reply. I have added org.opencontainers.image.ref.name label, but without a date, as this I believe is supposed to be stable label (people would use it to filter all centos-6-i386 images). I'm a bit afraid of a super long description you have provided as example. Git commit should be available, but I've set it to be full commit ID. I hope this works. Look forward to your feedback.

[jperrin]

Sorry for the delay in reviewing this. We've recently made some changes to the kickstart names. Do the changes there break your KSNAME RELEASEVER variable changes?