Kubernetes fails to pull image with unknown blob error

1. What causes this unknown blob error? Does it have to do with a Windows container/Linux container mismatch?It's because you're trying to run a Windows-based Docker container on a Linux host. It has nothing directly to do with Kubernetes or AKS. Currently AKS is in preview and supports only Linux environments. To be more precise, when you provision your AKS cluster (az aks create), all your k8s minions (worker nodes) will be Linux boxes and thus will not be able to run Windows-based containers.

2. Does the agent pool profile affect all the nodes in the cluster, or just the "master" nodes?It affects the worker nodes and is used to group them together logically so you can better manage workload distribution. In the future, when AKS supports both Linux and Windows, you will be able to i.e. create agent pools based on OS type and instruct k8s to deploy your Windows-based services only to the Windows-based hosts (agents).

I'm not sure if this applies to you, because it may seem to be a new deployment but I had this for existing ones twice now in a GKE environment.I'm using an Ubuntu image with nodejs, all Linux based.For some reason it seems the image is damaged or something in the GKE setup thinks that.I can resolve the problem by pushing again to the registry and then point the deployment to the new image.

I can reproduce it by simply pulling the docker image from another authenticated machine like:

docker pull gcr.io/project-name/app-name@sha256:somelongrandomhash

That gives me the same error.Once I noticed that, I just repushed the image and it worked.So although it might be the OS base image difference causing it as others suggested, check a local pull to see if that works well.