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title content_type min-kubernetes-server-version
Verify Signed Container Images task v1.24

{{< feature-state state="alpha" for_k8s_version="v1.24" >}}

{{% heading "prerequisites" %}}

These instructions are for Kubernetes {{< skew currentVersion >}}. If you want to check the integrity of components for a different version of Kubernetes, check the documentation for that Kubernetes release.

You will need to have the following tools installed:

  • cosign (install guide)
  • curl (often provided by your operating system)

Verifying image signatures

For a complete list of images that are signed please refer to Releases.

Let's pick one image from this list and verify its signature using the cosign verify command:

COSIGN_EXPERIMENTAL=1 cosign verify k8s.gcr.io/kube-apiserver-amd64:v1.24.0

{{< note >}} COSIGN_EXPERIMENTAL=1 is used to allow verification of images signed in KEYLESS mode. To learn more about keyless signing, please refer to Keyless Signatures . {{< /note >}}

Verifying images for all control plane components

To verify all signed control plane images, please run this command:

curl -Ls https://sbom.k8s.io/$(curl -Ls https://dl.k8s.io/release/latest.txt)/release | grep 'PackageName: k8s.gcr.io/' | awk '{print $2}' > images.txt
input=images.txt
while IFS= read -r image
do
  COSIGN_EXPERIMENTAL=1 cosign verify "$image"
done < "$input"

Once you have verified an image, specify that image by its digest in your Pod manifests as per this example: registry-url/image-name@sha256:45b23dee08af5e43a7fea6c4cf9c25ccf269ee113168c19722f87876677c5cb2 .

For more information, please refer to Image Pull Policy section.

Verifying Image Signatures with Admission Controller

For non-control plane images ( e.g. conformance image) , signatures can also be verified at deploy time using cosigned admission controller. To get started with cosigned here are a few helpful resources: