A first glance at the preview AKS (Azure Kubernetes Service)

Introduction

Today the new “AKS” (Azure Kubernetes Services) was launched in preview. This is a managed container service. So where ACS used to rely on IaaS and used a set of best practices to deploy the cluster. AKS will go a step further, where it’ll managed the master nodes & provide upgrade tracks.

 

Deploying

Let’s start with deploying an AKS cluster… Here we can select the k8s (kubernetes) version too.

Continue reading “A first glance at the preview AKS (Azure Kubernetes Service)”

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Issue : Failed to pull image : rpc error: code = 2 desc = unknown blob

Introduction

When you are deploying an image, which is hosted on a private registry, to a kubernetes (k8s) cluster with windows nodes… Then you might get the following error ;

Failed to pull image “kvaes.azurecr.io/kvaes2017:v1“: rpc error: code = 2 desc = unknown blob
Error syncing pod, skipping: failed to “StartContainer” for “private-reg-container” with ErrImagePull: “rpc error: code = 2 desc = unknown blob”

 

Context

So what did my setup look like?

  • Orchestrator : Kubernetes for Windows (Azure Container Service)
  • Registry : Private (Azure Container Registry)
  • Image : Windows Nano Based

 

Technical Check

Let’s deploy two pods…

The first I’ll deploy via yaml, which is basically the example from the kubernetes docs on pulling an image from a private repo

Now the second one is an adaptation of the example flow from the Azure Container Service documentation ;

Now let’s see how that one went…

The first one failed, and the second one passed! What was the difference?

 "nodeSelector": {
    "beta.kubernetes.io/os": "windows"
    }

Apparently this one forces the switch to “windows container mode” (or something like that…). As it seems very similar to the following thread

 

TL;DR

When deploying windows containers to a kubernetes cluster. be sure to the set the “nodeSelector” or you might end up with errors on pulling the image.