K8S Load Docker Image

This article provides a comprehensive guide on building, uploading, and loading Docker images for Kubernetes-based microk8s or Minikube. Additionally, it covers the process of importing images specifically for lightweight K3s distribution that utilizes the Docker container runtime.

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first of all, you can build and upload docker image to registry.

docker login
docker build -t <username>/<imagename>:<tag> -f <dockerfile> <resource_path>
docker push <username>/<imagename>:<tag>

you can upload to docker.io or microk8s provided local registry.

https://microk8s.io/docs/registry-built-in

# for microk8s the registry address is localhost:32000
docker tag <imagename> <registry_addr>/<imagename>
docker push <registry_addr>/<imagename>

you can also build image with minikube:

minikube image build -t <imagename> -f <dockerfile_path> <resource_path>

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load image exported with docker save <image>:<tag>

# ref: https://minikube.sigs.k8s.io/docs/commands/image/
# remember to set a tag to the image imported
# or set the imagePullPolicy to Never
# ref: https://iximiuz.com/en/posts/kubernetes-kind-load-docker-image/
minikube image load <image_filepath>/<docker_image_name>
microk8s images import <image_filepath>
microk8s ctr image import <image_filepath>
k3s ctr image import <image_filepath>

https://blog.scottlowe.org/2020/01/25/manually-loading-container-images-with-containerd/

https://docs.k3s.io/installation/registry-mirror#pushing-images

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you can also configure k8s to use docker as container runtime instead.

https://github.com/canonical/microk8s/issues/287

https://docs.k3s.io/advanced#using-docker-as-the-container-runtime