AKS Spot VMs

Azure Spot VMs offer significant cost savings for GPU workloads but can be evicted by Azure at any time. This guide covers the configuration required to schedule Dynamo on Spot VM node pools.

How AKS Taints Spot Nodes

When a node pool uses Spot VMs, AKS automatically applies the following taint to all nodes in that pool:

1
kubernetes.azure.com/scalesetpriority=spot:NoSchedule

This prevents standard workloads from landing on Spot nodes by default. Any pod that should run on a Spot node must explicitly tolerate this taint.

Required Toleration

Add the following toleration to any workload that should run on Spot nodes:

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tolerations:
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  - key: kubernetes.azure.com/scalesetpriority
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    operator: Equal
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    value: spot
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    effect: NoSchedule

Deploying Dynamo on Spot Nodes

The Dynamo platform Helm chart includes a pre-built values file for Spot VM deployments — examples/deployments/AKS/values-aks-spot.yaml — which adds the required toleration to all Dynamo components:

• Dynamo operator controller manager
• Webhook CA inject and cert generation jobs
• etcd
• NATS
• MPI SSH key generation job
• Other core Dynamo platform pods

Install Dynamo with the Spot values file:

$
helm install dynamo-platform dynamo-platform-${RELEASE_VERSION}.tgz \
>
  --namespace dynamo-system \
>
  --create-namespace \
>
  -f ./values-aks-spot.yaml

To upgrade an existing installation:

$
helm upgrade dynamo-platform dynamo-platform-${RELEASE_VERSION}.tgz \
>
  --namespace dynamo-system \
>
  -f ./values-aks-spot.yaml

Creating a Spot GPU Node Pool

Add a Spot GPU node pool to an existing AKS cluster:

$
az aks nodepool add \
>
  --resource-group <RESOURCE_GROUP> \
>
  --cluster-name <CLUSTER_NAME> \
>
  --name spotgpunp \
>
  --node-count 2 \
>
  --node-vm-size Standard_NC24ads_A100_v4 \
>
  --priority Spot \
>
  --eviction-policy Delete \
>
  --spot-max-price -1 \
>
  --skip-gpu-driver-install

--spot-max-price -1 means pay up to the on-demand price (recommended). --eviction-policy Delete removes evicted nodes from the pool; use Deallocate if you want to preserve node state across evictions.

See Also

• Azure Spot VMs overview
• Use Spot VMs in AKS