Azure Discounts: Reservations, Hybrid Benefit and Spot VMs

The Azure discount rules cover three mechanisms. Reservations commit to capacity for a term. Azure Hybrid Benefit applies Windows Server licences you already hold. Spot runs interruptible work on spare capacity. A fourth rule handles the reverse case: moving non-production VMs off a reservation onto Spot.

Azure Hybrid Benefit

Azure Hybrid Benefit Opportunity fires on Windows VMs that are not already using a Windows licence type or Hybrid Benefit. The saving is priced as the difference between the Windows and Linux rates for the same size, computed by ZopNight’s cost engine, so it reflects the licence component only. It applies to running VMs and also to VMs on a reservation or savings plan, where the licence component can still be reduced. The change is a licensing setting, and in the remediation wizard it is reversible through the configure step.

Reservations

• Azure Reserved VM Opportunity targets production VMs, or VMs with continuous-run evidence, that pass the commitment gate of at least 60 days of history with sustained uptime and utilization. It skips VM scale set members and Databricks-managed VMs.
• Azure SQL Reserved Capacity skips serverless databases and requires 60 days of history, uptime of at least 70% and measured CPU of at least 30%.
• Azure Redis Cache Could Use Reserved Capacity applies a tier gate: Microsoft sells cache reservations for the Premium, Enterprise and Enterprise Flash tiers, not for Basic or Standard.
• Azure MySQL Flexible Server Reserved Capacity reads the server’s own CPU and memory metrics before suggesting a term.

Every commitment finding is advisory and priced from the Azure Retail Prices feed for each 1-year and 3-year term it lists. ZopNight reads Azure costs as amortized, so reservation and savings plan purchases are spread across their terms and each covered resource shows its effective daily cost; already-covered resources do not re-fire.

Spot

• Azure Spot VM Opportunity requires positive evidence a VM is non-production, and vetoes stateful workloads, disaster-recovery and standby roles, and VMs already covered by a reservation.
• AKS Spot Node Pool Opportunity targets dev/test node pools and prices the saving from live Spot and on-demand rates.
• Azure RI to Spot Migration for Non-Production looks at reserved non-production VMs that could run on Spot instead.

Related

Fact sheets: Azure VMs, Azure SQL Database, Azure Cache for Redis, AKS node pools. Service pages: Azure Virtual Machines, Azure AKS. Background: reserved instances, Spot instances. Full list: Azure recommendations.