Azure AKS worker node disk billing concern

raymak 1 Reputation point
2020-12-17T13:25:24.113+00:00

I am doing a POC on AKS in Azure. So far I have AKS cluster running with standard_B2s sku worker node to evaluate cost for development workload. If I understand correctly, the prices shown in Azure pricing calculator for VM doesn't include OS disk price, correct? The reason I ask is because I am noticing the billing cost increasing from around $30-$40 to forecasted $72 for single node cluster. I assume that the cost of OS disk is playing a huge cost here. The increase is almost double on what I am expecting.

Cost analysis screenshot

To know what I did to setup the cluster. Here is the command I executed. 

az aks create -n aks-dev \
--resource-group $RESOURCEGROUP \
--location eastus2 \
--kubernetes-version 1.18.10 \
--load-balancer-sku basic \
--nodepool-name default \
--node-count 1 \
--node-vm-size Standard_B2s  \
--node-osdisk-size 50 \
--ssh-key-value ./id_rsa.pub \
--network-plugin kubenet \
--service-principal $SERVICE_PRINCIPAL \
--client-secret "$SERVICE_PRINCIPAL_SECRET" \
--output json
Azure Cost Management
Azure Cost Management
A Microsoft offering that enables tracking of cloud usage and expenditures for Azure and other cloud providers.
2,048 questions
Azure Kubernetes Service (AKS)
Azure Kubernetes Service (AKS)
An Azure service that provides serverless Kubernetes, an integrated continuous integration and continuous delivery experience, and enterprise-grade security and governance.
1,865 questions

1 answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. prmanhas-MSFT 17,891 Reputation points Microsoft Employee
    2020-12-18T16:27:23.293+00:00

    @raymak Apologies for all the delay in response and all inconvenience caused because of the issue.

    According to Azure pricing, the costs of cluster management are technically “free.” Instead, users pay for all of the nodes that the containers are built upon. Running AKS means only paying for the VMs that are provisioned, storage that your teams might use, and any data transfer costs involved.

    There are 2 models mainly in AKS for pricing:

    1)Pay-As-You Go
    2)Reserved and Spot Instances

    You can read more about it here

    In Azure Calculator it calculates the price based upon specification which do include Managed OS Disk Price. So for Standard HDD for a 32GB single disk it is 1.54$ per month based on which you can add OS Disks accordingly.

    When looking towards the compute, the VM family will have an impact of course. T As you can imagine, a machine with 1 core and 2GB of memory will cost less than a machine with 10TB of memory. So choosing the right size that aligns with your needs is already a crucial step. You can read more about it here

    So the cost which you see in Pricing Calculator is more around VM family you are using for the purpose rather than OS Disks.

    Also you can use Reserve Instances and Spot Instances for saving more as per your requirement. You can read more about it here.

    Hope it helps!!!

    Please "Accept as Answer" so it can help others in community looking for help on similar topics.

    0 comments