Public Preview: Zone Support for Standby Pools in Azure Container Instances

Microsoft

May 14, 2025

We’re excited to announce that zone support for standby pools in Azure Container Instances (ACI) is now available in public preview! This new capability brings enhanced resiliency and placement control to your containerized workloads by allowing you to distribute standby capacity across availability zones.

What’s New?

With zone support, you can now configure your ACI standby pools to span one or more availability zones within a region. This enables:

Improved fault tolerance: Spread standby containers across zones to mitigate the impact of zone-level outages.
Faster recovery: Maintain warm capacity in multiple zones for quicker failover.
Better placement control: Align standby capacity with your application’s architecture and regional strategy.

Supported Regions

Zone support for ACI standby pools is currently available in the following regions:

AustraliaEast
BrazilSouth
CanadaCentral
CentralUS
EastUS
EastUS2
FranceCentral
GermanyWestCentral
IndiaCentral
JapanEast
NorthEurope
SoutheastAsia
SouthCentralUS
SwedenCentral
WestEurope
WestUS
WestUS2
WestUS3

How to Use It

You can specify zones when creating a standby pool using various SDKs such as CLI, PowerShell, and REST.

az standby-container-group-pool create \
   --resource-group myResourceGroup \
   --location WestUS \
   --name myStandbyPool \
   --max-ready-capacity 20 \
   --refill-policy always \
   --zones 1,2,3 \
   --container-profile-id "/subscriptions/{subscriptionId}/resourceGroups/myResourceGroup/providers/Microsoft.ContainerInstance/containerGroupProfiles/mycontainergroupprofile"

When requesting a container from the pool, simply include which zone you want to pull from in the container create command:

az container create \
   --resource-group myResourceGroup \
   --name mycontainer \
   --location WestUS \
   --zone 1 \
   --container-group-profile-revision 1 \
   --container-group-profile-id "/subscriptions/{subscriptionId}/resourceGroups/myResourceGroup/providers/Microsoft.ContainerInstance/containerGroupProfiles/mycontainergroupprofile" \
   --standby-pool-profile-id "/subscriptions/{subscriptionId}/resourceGroups/myResourceGroup/providers/Microsoft.StandbyPool/standbyContainerGroupPools/myStandbyPool"

Why It Matters

Standby pools are designed to reduce cold start latency by pre-provisioning container groups that can be reused instantly. With zone support, you can now ensure that this standby capacity is resilient and distributed, making it even more suitable for production-grade, multi-zone deployments.