Azure Kubernetes Service (AKS)
The AKS SLA only ever covers the Kubernetes API server, never your workloads. There is no native multi-region failover for a cluster — cross-region resilience is a fully custom architecture.
Free tier / single-zone node pool
Free pricing tier and/or node pools without Availability Zone spread. Recommended only for dev/test.
- Replication
- None
- RPO
- N/A
- RTO
- N/A — best-effort only
- Failover trigger
- N/A
Free tier has no financially backed SLA at all, for any failure scenario.
Standard/Premium tier with zone-spread node pools
Control plane and node pools spread across Availability Zones. Kubernetes self-healing (pod rescheduling, node autoscaling) plus AZ placement handles zone loss.
- Replication
- None
- RPO
- 0 for stateless workloads — stateful workloads depend entirely on the backing data tier's own zonal redundancy
- RTO
- Minutes — pod rescheduling and node replacement are automatic but not instant
- Failover trigger
- Automatic
The 99.95% SLA covers API server availability only — it says nothing about whether your pods are healthy or serving traffic.
No native feature — custom multi-cluster architecture
AKS has no built-in cross-region failover. The standard pattern is independent clusters per region, configuration synced via GitOps, and traffic steered by Front Door/Traffic Manager. Stateful data replication is entirely the backing store's responsibility.
- Replication
- N/A
- RPO
- Entirely dependent on your architecture and the data stores behind it
- RTO
- Entirely dependent on your architecture — DNS/routing failover plus cluster and application readiness
- Failover trigger
- N/A
Gotchas
The uptime SLA is about the control plane, not your app
99.95%/99.9% covers Kubernetes API server availability. A perfectly healthy control plane tells you nothing about whether deployments, services, or pods are actually up — that's on your own health checks and readiness probes.
There is no 'AKS regional failover' feature to configure
This is the single most common gap found in AKS resiliency reviews: teams assume multi-region is a setting to enable, when it's actually a from-scratch architecture involving duplicate clusters, GitOps-driven config sync, and a global load balancer — none of which AKS provides out of the box.
Free tier in production is an invisible risk
Nothing stops a Tier 1–3 workload from quietly running on a Free-tier cluster with no financially backed SLA — it looks identical to Standard in the portal until you check the tier setting.