Image And Container Label Specification

---

Introduction

We in the IT team need to know quickly when we have a container in front of us and want to answer the following questions:

• Who can I contact if I have problems with the container or the container is no longer running?
• Until when is the container still needed or can I switch it off and remove it in an emergency?
• How was the container created if it needs to be updated and the contact person cannot be reached?

Hence, this topic summarizes our current best practices regarding labelling container images and instances. It is based on the opencontainers image specification pre defined annotation keys.

Labels

Key	Schema	Example	Description
Images
org.opencontainers.image.created	RFC 3339 string	2020-12-03T09:15:13+00:00 2020-12-03T09:15:13Z	date and time on which the image was built (string, date-time as defined by RFC 3339) - via build ARG - see example for more details
org.opencontainers.image.authors	free form string	J. Doe <j.doe@example.com>, Q. Public <qpub@company.example.com>	Contact details of the people or organization responsible for the image (freeform string)
org.opencontainers.image.url	URL	https://github.com/52North/SOS.git	URL to find more information on the image, e.g. link to git repo with Dockerfile.
org.opencontainers.image.version	semver string	v5.2.42	Version of the packaged software.
org.opencontainers.image.revision	string	r2530 bd4f8fcb	Source control revision identifier for the packaged software via build ARG.
org.opencontainers.image.vendor	string	52°North GmbH	Name of the distributing entity, organization or individual.
org.opencontainers.image.licenses	SPDX license expression	GPL-2.0-only GPL-2.0-or-later GPL-3.0-only GPL-3.0-or-later Apache-2.0	License(s) under which contained software is distributed as an SPDX License Expression., e.g. https://spdx.org/licenses/Apache-2.0, https://spdx.org/licenses/GPL-3.0-or-later
org.opencontainers.image.ref.name	grammar	52north/sos-5.2.42	Name of the reference for a target.
org.opencontainers.image.title	string	52°North Sensor Observation Service	Human-readable title of the image.
org.opencontainers.image.description	string		Really required and usefull
Container
org.52north.contact	E-Mail	j.doe+sos-instance-for-project-xyz@example.com	e-mail from the person responsible for this service instance. Use mail tagging for better mail processing.
org.52north.context	string	wacodis-2020	project abbreviation and year.
org.52north.end-of-life	RFC 3339 string	2020-12-03T09:15:13+00:00 2020-12-03T09:15:13Z	date and time as defined by RFC 3339. After this point in time, the container including the associated resources can be deleted automatically or manually at any time.
Volumes
org.52north.backup	boolean string, true or false or empty which equals false	true	optional: If set to true, the volume is backed up daily.

Example Git Repository

https://github.com/52North/label-spec/