Spot VM caveats

Spot VMs are not without trade-offs. Evaluate whether your workload can benefit from the price discount without impacting its availability, reliability, and security aspects. Let’s understand the eviction policy and limitations of spot VMs.

Eviction type and policy

What is eviction? Spot VMs do not have any service-level agreement (SLA) and they can lose the compute anytime with 30 seconds’ notice. This loss is called eviction. Eviction is driven by supply and demand in a specific region. When a certain VM SKU demand goes too high, the platform starts evaluating the Spot VMs to accommodate new pay-as-you-go VMs. Spot VMs have two configurations for eviction: Eviction type and Eviction policy.

Eviction type defines the condition of the eviction. There are two types – Capacity only and Price or capacity. When Azure’s excess compute capacity disappears, it triggers the Capacity only eviction in which Spot VM prices are not fixed and...