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Migrate Batch low-priority VMs to Spot VMs

  • Artikkeli

The ability to allocate low-priority compute nodes in Azure Batch pools is being retired on September 30, 2025. Learn how to migrate your Batch pools with low-priority compute nodes to compute nodes based on Spot instances.

About the feature

Currently, as part of a Batch pool configuration, you can specify a target number of low-priority compute nodes for Batch managed pool allocation Batch accounts. In user subscription pool allocation Batch accounts, you can specify a target number of spot compute nodes. In both cases, these compute resources are allocated from spare capacity and offered at a discount compared to dedicated, on-demand VMs.

The amount of unused capacity that's available varies depending on factors such as VM family, VM size, region, and time of day. Unlike dedicated capacity, these low-priority or spot VMs can be reclaimed at any time by Azure. Therefore, low-priority and spot VMs are typically viable for Batch workloads that are amenable to interruption or don't require strict completion timeframes to potentially lower costs.

Feature end of support

Only low-priority compute nodes in Batch are being retired. Spot compute nodes will continue to be supported, is a GA offering, and not affected by this deprecation. On September 30, 2025, we'll retire low-priority compute nodes. After that date, existing low-priority pools in Batch may no longer be usable, attempts to seek back to target low-priority node counts will fail, and you'll no longer be able to provision new pools with low-priority compute nodes.

Alternative: Use Azure Spot-based compute nodes in Batch pools

As of December 2021, Azure Batch began offering Spot-based compute nodes in Batch. Like low-priority VMs, you can use spot instances to obtain spare capacity at a discounted price in exchange for the possibility that the VM will be preempted. If a preemption occurs, the spot compute node will be evicted and all work that wasn't appropriately checkpointed will be lost. Checkpointing is optional and is up to the Batch end-user to implement. The running Batch task that was interrupted due to preemption will be automatically requeued for execution by a different compute node. Additionally, Azure Batch will automatically attempt to seek back to the target Spot node count as specified on the pool.

See the detailed breakdown between the low-priority and spot offering in Batch.

Migrate a Batch pool with low-priority compute nodes or create a Batch pool with Spot instances

  1. Ensure that you're using a user subscription pool allocation mode Batch account.

  2. In the Azure portal, select the Batch account and view an existing pool or create a new pool.

  3. Under Scale, select either Target dedicated nodes or Target Spot/low-priority nodes.

    Screenshot that shows how to scale target nodes.

  4. For an existing pool, select the pool, and then select Scale to update the number of spot nodes required based on the job scheduled.

  5. Select Save.

FAQs

  • How do I create a user subscription pool allocation Batch account?

    See the quickstart to create a new Batch account in user subscription pool allocation mode.

  • Are Spot VMs available in Batch managed pool allocation accounts?

    No. Spot VMs are available only in user subscription pool allocation Batch accounts.

  • Are spot instances available for CloudServiceConfiguration Pools?

    No. Spot instances are only available for VirtualMachineConfiguration pools. CloudServiceConfiguration pools will be retired before low-priority pools. We recommend that you migrate to VirtualMachineConfiguration pools and user subscription pool allocation Batch accounts before then.

  • What is the pricing and eviction policy of spot instances? Can I view pricing history and eviction rates?

    Yes. In the Azure portal, you can see historical pricing and eviction rates per size in a region.

    For more information about using spot VMs, see Spot Virtual Machines.

  • Can I transfer my quotas between Batch accounts?

    Currently you can't transfer any quotas between Batch accounts.

Next steps

See the Batch Spot compute instance guide for details on further details in the difference between offerings, limitations, and deployment examples.