probably a dumb question but I ve build a docker image which rancher-users #rancher-desktop

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tall-kite-83186

06/01/2022, 12:09 PM

probably a dumb question. but I've build a docker image which is now in my private registry. While trying to install in K3s I install the related chart and reference my docker image directly but K8s pod complains it cannot find the image (imagePullBackoff). How do I tell K3s to use RD registry from wsl?

miniature-advantage-69986

06/01/2022, 3:32 PM

what did you meen with "privat registry"? If you do a docker build and tag the image you should be able to see the image with "docker image ls", after this you can create a pod with this image but make sure that the imagePullPolicy is set to "IfNotPresent" otherwise K3S will try to pull the image from dockerhub.

tall-kite-83186

06/01/2022, 3:36 PM

I can definitely see the image when doing

nerdctl images

. I'll try the pullPolicy

Just changed the policy, now I have this:

Failed to pull image "haproxy-agent-service-checker:latest": rpc error: code = Unknown desc = failed to pull and unpack image "<http://docker.io/library/haproxy-agent-service-checker:latest|docker.io/library/haproxy-agent-service-checker:latest>": failed to resolve reference "<http://docker.io/library/haproxy-agent-service-checker:latest|docker.io/library/haproxy-agent-service-checker:latest>": pull access denied, repository does not exist or may require authorization: server message: insufficient_scope: authorization failed

And the complementary event:

Back-off pulling image "haproxy-agent-service-checker:latest"

I don't get why k3s tries to pull from docker instead of local registry

# nerdctl images
REPOSITORY                       TAG       IMAGE ID        CREATED         PLATFORM       SIZE         BLOB SIZE
haproxy-agent-service-checker    latest    164609860dc6    4 hours ago     linux/amd64    107.1 MiB    39.3 MiB

tall-insurance-55443

06/01/2022, 3:50 PM

You need to do something very similar to this https://docs.rancherdesktop.io/how-to-guides/hello-world-example#build-image-from-code-locally

specifically

nerdctl --namespace <http://k8s.io|k8s.io> build --tag nginx-helloworld:latest .

tall-kite-83186

06/01/2022, 3:50 PM

Can't I build onto default registry and let K3s to pick in it?

Or is it bound to k8s.io ?

tall-insurance-55443

06/01/2022, 3:52 PM

🤷 I don’t know K3 well enough TBH But it’s one way or the other (either push it where k8s knows, or change where k8s is looking)

fast-garage-66093

06/01/2022, 4:39 PM

@tall-insurance-55443 is correct: you need to build the image in the

<http://k8s.io|k8s.io>

namespace for kubernetes to "see" it. Note that these are containerd namespaces, not kubernetes namespaces, which may contribute to the confusion

tall-kite-83186

06/01/2022, 4:40 PM

Indeed it confuses. Can't we allow K3s to see default containerd namespace ?

fast-garage-66093

06/01/2022, 4:44 PM

No, this is the way k8s and containerd work; I'm not sure this is configurable, but even if it were, I would strongly recommend against it.

tall-kite-83186

06/01/2022, 4:44 PM

That's fine, I'll stick with k8s.io namespace

fast-garage-66093

06/01/2022, 4:46 PM

Note that this namespace is "owned" by kubernetes, so if you would create a container in it, kubelet would just kill it as soon as it notices. For that reason

nerdctl -n <http://k8s.io|k8s.io> build ...

does not actually build in the target namespace, but copies/links the image over, so kubelet can see it.

tall-kite-83186

06/01/2022, 4:46 PM

Gotcha

Hmmm, for some reasons I still have the same issues pulling the image from k8s.io internal registry:

fast-garage-66093

06/01/2022, 5:27 PM

Oh, this is because you are using the

latest

tag. It implies

imagePullPolicy: Always

, so kubelet will check if there is a newer version of the image on the registry. You need to either specify

imagePullPolicy: Never

in your Pod spec, or use any tag other than

latest

https://kubernetes.io/docs/concepts/containers/images/#image-pull-policy

tall-kite-83186

06/01/2022, 5:29 PM

You got it!

Thank you Jan

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