4.2.14.2 LABEL Maintainer Field

The LABEL maintainer field records who is responsible for an image — typically a team name, an email address, or both — directly within the image's own metadata, replacing the older, now-deprecated MAINTAINER instruction that previously served this same purpose as a dedicated instruction.

Setting the Maintainer Label

Rather than using the deprecated MAINTAINER instruction, the conventional approach is to set a maintainer label directly.

LABEL maintainer="platform-team@example.com"

Why MAINTAINER Was Deprecated in Favor of LABEL

The dedicated MAINTAINER instruction was deprecated because LABEL provides a more general, flexible mechanism that can express the same information alongside any other metadata, without needing a special-purpose instruction just for this one specific field.

MAINTAINER team@example.com

LABEL maintainer="team@example.com"

The second form achieves the same result, using the more general-purpose mechanism that also supports arbitrary additional metadata.

Recording More Than Just an Email Address

The maintainer label is not limited to a single email address; it can reflect a team name, a link to a relevant internal page, or any other identifying information that helps someone determine who to contact about the image.

LABEL maintainer="Platform Team <platform-team@example.com>"

Verifying the Maintainer Label

The recorded maintainer information can be retrieved directly from a built image, without needing to consult separate documentation or the original Dockerfile.

docker inspect myapp:1.0 --format '{{index .Config.Labels "maintainer"}}'

Why Recording Maintainer Information Matters

In any organization maintaining more than a handful of images, knowing who to contact about a specific image — whether to ask a question, report an issue, or request a change — saves significant time compared to needing to track this information down separately, making the maintainer label a small but genuinely useful piece of metadata to keep accurate.