Azure Idle Resources: Plans, Gateways, Caches and Pools

Several Azure services bill for provisioned capacity rather than use. In the dedicated tiers an App Service Plan is charged for each VM instance it defines, whether it hosts ten apps or none, and a Synapse dedicated SQL pool charges for compute until it is paused. The Azure idle rules find those cases from Azure Monitor metrics and Resource Graph properties, and each names the lever that recovers the cost.

Plans that host nothing

• Idle Azure App Service Plan fires when a plan hosts zero apps, read from the plan’s site count in Resource Graph. The saving is the full plan fee.
• Idle Azure Function App fires only on Premium or Dedicated hosting plans. Consumption-plan apps abstain, because the rule finds no standing plan charge to reclaim there. It is advisory: stopping the app halts its triggers but does not release the plan the saving is priced on.

See App Service Plans, Function Apps and Azure Functions.

Network edge

Idle Azure Application Gateway fires on zero requests over the window. Azure Load Balancer with No Backends checks both the backend pool and measured byte and packet counts. Azure Firewall Idle requires three metric series covered for 30 days. Idle Azure NAT Gateway fires when no bytes were processed for 30 days.

Data services

• Azure Redis Cache Idle needs both connected clients and operations below floor, on average and at peak.
• Azure PostgreSQL Server Idle and Idle Azure SQL Managed Instance. For a managed instance the lever is a one-step vCore downsize, not a delete, because removing a managed database is not a reversible action.
• Idle Azure SQL Database is advisory. For serverless databases the saving comes from auto-pause; for provisioned DTU databases it is a tier step-down. See Azure SQL Database.

Analytics and ML pools

Azure Synapse SQL Pool Idle prices compute only, since pausing a dedicated pool leaves storage billing. Idle Azure ML Compute fires when a cluster keeps a minimum node count above zero with no active nodes, and prices only those warm minimum nodes. Both Synapse pools and ML Compute are on ZopNight’s reversible pause roster. See Azure ML Compute.

Messaging and registries

Azure Event Hub Idle and Azure Service Bus Idle run through remediation as deletes with precondition and approval steps. Azure Container Registry Idle is priced on the registry’s fixed monthly charge, and its fix is removal rather than a schedule.

Idle VMs route to schedules

A quiet Azure VM is titled “Schedule … to stop during off-hours”, not deleted: Idle Azure VM recommends a recurring window, and the one-shot stop is demoted to advisory by the safety gate. See Azure Virtual Machines and schedule recommendations. Full list: Azure recommendations.