Image Metadata and Labels

Applies to: Both legacy and user namespace modes

Required Labels (Certification)

Red Hat container certification tests for six mandatory labels via the HasRequiredLabel check. All six must be present in the Containerfile:

Label Purpose Example
name Image name (human-readable) mycompany/myapp
vendor Company name My Company, Inc.
version Image version 1.2.3
release Build release number 1
summary Short description (≤80 chars) My Application Server
description Long description My Application Server provides...

Example

LABEL name="mycompany/myapp" \
      vendor="My Company, Inc." \
      version="1.2.3" \
      release="1" \
      summary="My Application Server" \
      description="My Application Server provides a REST API for..." \
      maintainer="team@mycompany.com"

Use a single LABEL instruction to avoid creating extra layers.

OpenShift-Specific Labels

These labels enable integration with the OpenShift console, catalog, and generation tools:

Label Type Purpose Example
io.openshift.tags comma-separated strings Categories for catalog/discovery nodejs,web,api
io.openshift.wants comma-separated strings Dependency hints — UI suggests adding these mongodb,redis
io.openshift.expose-services PORT[/PROTO]:NAME list Describe what services the ports provide 8080:http,8443:https
io.openshift.non-scalable boolean Image doesn’t support replicas > 1 true
io.openshift.min-memory K8s quantity Minimum memory hint 512Mi
io.openshift.min-cpu K8s quantity Minimum CPU hint 500m

Kubernetes Labels

Label Purpose Example
io.k8s.display-name Human-readable name for UI My App 1.2
io.k8s.description Description for K8s tools REST API server for...

OCI Standard Labels

These follow the OCI image spec (org.opencontainers.image.*):

Label Purpose
org.opencontainers.image.title Human-readable title
org.opencontainers.image.description Description
org.opencontainers.image.version Version
org.opencontainers.image.vendor Vendor
org.opencontainers.image.url Project URL
org.opencontainers.image.source Source code URL
org.opencontainers.image.licenses SPDX license expression
org.opencontainers.image.created Build timestamp (RFC 3339)

Complete Label Block Example

LABEL name="mycompany/myapp" \
      vendor="My Company, Inc." \
      version="1.2.3" \
      release="1" \
      summary="REST API server for widget management" \
      description="Provides CRUD operations for widget resources with PostgreSQL backend" \
      maintainer="platform-team@mycompany.com" \
      # OpenShift integration
      io.openshift.tags="api,rest,nodejs" \
      io.openshift.wants="postgresql" \
      io.openshift.expose-services="8080:http" \
      # Kubernetes
      io.k8s.display-name="Widget API Server" \
      io.k8s.description="REST API server for widget management" \
      # OCI
      org.opencontainers.image.title="Widget API Server" \
      org.opencontainers.image.version="1.2.3" \
      org.opencontainers.image.vendor="My Company, Inc." \
      org.opencontainers.image.source="https://github.com/mycompany/myapp" \
      org.opencontainers.image.licenses="Apache-2.0"

S2I Labels

Only needed if the image is a Source-to-Image builder image. See S2I Compatibility for details.

Label Purpose
io.openshift.s2i.scripts-url URL/path to assemble/run scripts
io.openshift.s2i.destination Working directory for S2I (default /tmp)

Gotchas

Sources