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Azure Kubernetes Service (AKS) node pool snapshot

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AKS releases a new node image weekly. Every new cluster, new node pool, or upgrade cluster always receives the latest image, which can make it hard to maintain consistency and have repeatable environments.

Node pool snapshots allow you to take a configuration snapshot of your node pool and then create new node pools or new clusters based of that snapshot for as long as that configuration and kubernetes version is supported. For more information on the supportability windows, see Supported Kubernetes versions in AKS.

The snapshot is an Azure resource that contains the configuration information from the source node pool, such as the node image version, kubernetes version, OS type, and OS SKU. You can then reference this snapshot resource and the respective values of its configuration to create any new node pool or cluster based off of it.

Before you begin

This article assumes that you have an existing AKS cluster. If you don't have an AKS cluster, for guidance on a designing an enterprise-scale implementation of AKS, see Plan your AKS design.

Limitations

  • Any node pool or cluster created from a snapshot must use a VM from the same virtual machine family as the snapshot, for example, you can't create a new N-Series node pool based of a snapshot captured from a D-Series node pool because the node images in those cases are structurally different.
  • Snapshots must be created same region as the source node pool, those snapshots can be used to create or update clusters and node pools in other regions.

Take a node pool snapshot

In order to take a snapshot from a node pool, you need the node pool resource ID, which you can get from the following command:

NODEPOOL_ID=$(az aks nodepool show --name nodepool1 --cluster-name myAKSCluster --resource-group myResourceGroup --query id -o tsv)

Important

Your AKS node pool must be created or upgraded after Nov 10th, 2021 in order for a snapshot to be taken from it. If you are using the aks-preview Azure CLI extension version 0.5.59 or newer, the commands for node pool snapshot have changed. For updated commands, see the Node Pool Snapshot CLI reference.

Now, to take a snapshot from the previous node pool, you use the az aks snapshot CLI command.

az aks nodepool snapshot create --name MySnapshot --resource-group MyResourceGroup --nodepool-id $NODEPOOL_ID --location eastus

Create a node pool from a snapshot

First, you need the resource ID from the snapshot that was previously created, which you can get from the following command:

SNAPSHOT_ID=$(az aks nodepool snapshot show --name MySnapshot --resource-group myResourceGroup --query id -o tsv)

Now, we can use the following command to add a new node pool based off of this snapshot.

az aks nodepool add --name np2 --cluster-name myAKSCluster --resource-group myResourceGroup --snapshot-id $SNAPSHOT_ID

Upgrading a node pool to a snapshot

You can upgrade a node pool to a snapshot configuration so long as the snapshot kubernetes version and node image version are more recent than the versions in the current node pool.

First, you need the resource ID from the snapshot that was previously created, which you can get from the following command:

SNAPSHOT_ID=$(az aks nodepool snapshot show --name MySnapshot --resource-group myResourceGroup --query id -o tsv)

Now, we can use this command to upgrade this node pool to this snapshot configuration.

az aks nodepool upgrade --name nodepool1 --cluster-name myAKSCluster --resource-group myResourceGroup --snapshot-id $SNAPSHOT_ID

Note

Your node pool image version is the same contained in the snapshot and remains the same throughout every scale operation. However, if this node pool is upgraded or a node image upgrade is performed without providing a snapshot-id the node image is upgraded to the latest version.

Note

To upgrade only the node version for your node pool, use the --node-image-only flag. This is required when upgrading the node image version for a node pool based on a snapshot with an identical Kubernetes version.

Create a cluster from a snapshot

When you create a cluster from a snapshot, the snapshot configuration creates the cluster original system pool.

First, you need the resource ID from the snapshot that was previously created, which you can get from the following command:

SNAPSHOT_ID=$(az aks nodepool snapshot show --name MySnapshot --resource-group myResourceGroup --query id -o tsv)

Now, we can use this command to create this cluster off of the snapshot configuration.

az aks create \
    --name myAKSCluster2 \
    --resource-group myResourceGroup \
    --snapshot-id $SNAPSHOT_ID \
    --generate-ssh-keys

Next steps