Add pinned image selectors to exclude images from kubelet GC - #571
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athongsamai merged 1 commit intoSep 8, 2026
Merged
athongsamai merged 1 commit into
athongsamai merged 1 commit into
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The kubelet omits images the runtime reports as pinned from its
eviction list, but cri-dockerd only ever pinned the pod sandbox image.
Any other image that cannot simply be re-pulled -- a platform image
side-loaded onto an air-gapped node, for example -- is deleted once the
node crosses its image GC threshold.
Add two flags that let an operator pin additional images:
--pinned-images image references: a full "repo:tag" or
"repo@digest", a bare repository (pinning every
tag of it), or a prefix ending in '*'
--pinned-image-labels label selectors in "key" or "key=value" form,
pinning a whole set of images without
enumerating it
Matching lives in a new pinnedImageMatcher (core/pinned.go), which
NewDockerService builds once and ListImages/ImageStatus consult through
dockerService.isImagePinned. The sandbox image stays pinned
unconditionally, and a nil or empty matcher matches nothing, so the
default configuration behaves exactly as before. Reference parsing
treats a registry port as part of the repository rather than a tag.
ImageStatus now reads labels from the image inspect config so
label selectors apply to it as well as to ListImages.
chenyaooo
self-requested a review
September 4, 2026 14:46
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Fixes #
Why does this need?
The
kubeletomits images the runtime reports as pinned from its eviction list, butcri-dockerdonly ever pinned the pod sandbox image. Any other image that cannot simply be re-pulled -- a platform image side-loaded onto an air-gapped node, for example -- is deleted once the node crosses its image GC threshold.Proposed Changes
Add two flags that let an operator pin additional images:
--pinned-images: image references: a full "repo:tag" or "repo@digest", a bare repository (pinning every tag of it), or a prefix ending in '*'--pinned-image-labels: label selectors in "key" or "key=value" form, pinning a whole set of images without enumerating itMatching lives in a new
pinnedImageMatcher(core/pinned.go), whichNewDockerServicebuilds once andListImages/ImageStatusconsult throughdockerService.isImagePinned. The sandbox image stays pinned unconditionally, and a nil or empty matcher matches nothing, so the default configuration behaves exactly as before. Reference parsing treats a registry port as part of the repository rather than a tag.ImageStatusnow reads labels from the image inspect config so label selectors apply to it as well as toListImages.