(Updated by @ktock and me (@AkihiroSuda))

Summary

• ✅ : Supported
• ➖ : won't be possible
• blank: TBD

• eStargz is compatible with OCI Image Specification so OCI-compliant tools can handle it in the same way as non-eStargz standard images even if they aren't eStargz-aware.

Kubernetes and distros

Kubernetes

✅ Lazy pulling is possible by using containerd or CRI-O as CRI runtime

k3s

✅ Supported since k3s v1.22.
Doc: https://docs.k3s.io/advanced#enabling-lazy-pulling-of-estargz-experimental

kind

Use ghcr.io/containerd/stargz-snapshotter:0.12.1-kind node image
e.g.:

$ kind create cluster --name stargz-demo --image ghcr.io/containerd/stargz-snapshotter:0.12.1-kind

• There is a quick start on README: https://github.com/containerd/stargz-snapshotter#quick-start-with-kubernetes

CRI runtimes

containerd

✅ Lazy pulling is supported since containerd 1.4.0

CRI-O

✅ Lazy pulling is supported since v1.22 (which includes cri-o/cri-o#4850)

• limitation: chunk verification is not enabled

High-level container engines

Docker (Moby)

✅ Lazy pulling is supported since moby/moby@5c1d6c9

Podman

✅ Lazy pulling is supported since v3.3.0 (which includes containers/podman#10214)

• limitation: chunk verification is not enabled

nerdctl

Lazy pulling of eStargz

✅ Supported since nerdctl 0.0.1 https://github.com/containerd/nerdctl/blob/master/docs/stargz.md

Building eStargz images

✅ Supported since nerdctl 0.5.0 https://github.com/containerd/nerdctl/blob/master/docs/stargz.md

• Manual optimization is experimentally supported through --estargz-record-in option.

Image builders

BuildKit

Lazy-pulling base images

✅ Supported since BuildKit 0.8.0 https://github.com/moby/buildkit/blob/master/docs/stargz-estargz.md

Building eStargz images

✅ Supported since BuildKit v0.10.

Usage: buildctl build--output type=image,name=example.com/foo,push=true,compression=estargz,oci-mediatypes=true.

Kaniko

Lazy-pulling base images

❌ Won't be possible

Building eStargz images

✅ Supported since Kaniko 1.4.0 GoogleContainerTools/kaniko#1527

• GGCR_EXPERIMENT_ESTARGZ=1 needs to be specified.

Buildah

Lazy-pulling base images

TBD, will happen after Podman supports lazy-pulling

Building eStargz images

TBD

ko

Building eStargz images

✅ Supported since ko 0.7.0 ko-build/ko#271

• GGCR_EXPERIMENT_ESTARGZ=1 needs to be specified

buildpacks.io

Building eStargz images

✅ Supported since pack 0.16.0, lifecycle 0.10.2

• For pack builder create, build-image need to be pre-converted to eStargz. GGCR_EXPERIMENT_ESTARGZ=1 needs to be specified.
• For pack build, GGCR_EXPERIMENT_ESTARGZ=1 envvar needs to be configured to lifecycle-image. Thus the following image need to be used

  FROM buildpacksio/lifecycle:0.11.3
  ENV GGCR_EXPERIMENT_ESTARGZ=1

Registry clients

go-containerregistry and crane CLI

Converting image into eStargz

✅Supported since go-containerregistry 0.3.0 google/go-containerregistry#871

• GGCR_EXPERIMENT_ESTARGZ=1 needs to be specified.
• Manual optimization is supported through --prioritize option.

Registry

Harbor

✅Harbor Acceleration Service webhook enables converting an OCI image into eStargz on registry side.

https://github.com/goharbor/acceleration-service