Microsoft added a feature to support single-node clusters on the Azure Stack HCI operating system. Single-node clusters are similar to stand-alone Storage Spaces nodes but are delivered as an Azure service. Single-node clusters support all the Azure services that a multi-node Azure Stack HCI cluster supports. On a single-node cluster, there is no automatic provision of failover to another node. A physical disk is the fault domain in a single-node cluster and only a single-tier configuration (All-Flash or All-NVMe) is supported.
While node-level High Availability cannot be supported on a single-node cluster, you can choose application-level or VM-level replication to maintain High Availability in your infrastructure.