Image And Container Label Specification

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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
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)
Container
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.
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.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.opencontainers.image.title	string	52°North Sensor Observation Service	Human-readable title of the image.
Images
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.vendor	string	52°North GmbH	Name of the distributing entity, organization or individual.
org.opencontainers.image.ref.name	grammar	52north/sos-5.2.42	Name of the reference for a target.
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.
org.52north.context	string	wacodis-2020	project abbreviation and year.
org.opencontainers.image.description	string		Really required and usefull
org.opencontainers.image.revision	string	r2530 bd4f8fcb	Source control revision identifier for the packaged software via build ARG.
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.
Volumes

Example Git Repository

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