Ensure application high availability when running in VMware on Azure

The CloudSimple solution provides high availability for your applications running on VMware in the Azure environment. The following table lists failure scenarios and the associated high availability features.

Failure Scenario Application Protected? Platform HA Feature VMware HA Feature Azure HA Feature
Disk Failure YES Fast replacement of failed node About the vSAN Default Storage Policy
Fan Failure YES Redundant fans, fast replacement of failed node
NIC Failure YES Redundant NIC, fast replacement of failed node
Host Power Failure YES Redundant power supply
ESXi Host Failure YES fast replacement of failed node VMware vSphere High Availability
VM Failure YES Load balancers VMware vSphere High Availability Azure Load Balancer for stateless VMware VMs
Leaf Switch Port Failure YES Redundant NIC
Leaf Switch Failure YES Redundant leaf switches
Rack Failure YES Placement groups
Network Connectivity to on-premise DC YES Redundant networking services Redundant ER circuits
Network Connectivity to Azure YES Redundant ER circuits
Datacenter Failure YES Availability zones
Regional Failure YES Azure regions

High availability features

Fast replacement of failed node

The CloudSimple control plane software continuously monitors the health of VMware clusters and detects when an ESXi node fails. It then automatically adds a new ESXi host to the affected VMware cluster from its pool of readily available nodes and takes the failed node out of the cluster. This functionality ensures that the spare capacity in the VMware cluster is restored quickly so that the cluster’s resiliency provided by vSAN and VMware HA is restored.

Placement Groups

A user who creates a Private Cloud can select an Azure region and a placement group within the selected region. A placement group is a set of nodes spread across multiple racks but within the same spine network segment. Nodes within the same placement group can reach each other with a maximum of two extra switch hops. A placement group is always within a single Azure availability zone and spans multiple racks. The CloudSimple control plane distributes nodes of a Private Cloud across multiple racks based on best effort. Nodes in different placement groups are guaranteed to be placed in different racks.

Availability zones

Availability zones are a high-availability offering that protects your applications and data from datacenter failures. Availability zones are special physical locations within an Azure region. Each zone is made up of one or more datacenters equipped with independent power, cooling, and networking. Each region has one availability zone. For more information, see What are Availability Zones in Azure?

Redundant Azure ExpressRoute circuits

Data center connectivity to Azure vNet using ExpressRoute has redundant circuits to provide highly available network connectivity link.

Redundant networking services

All the CloudSimple networking services for the Private Cloud (including VLAN, firewall, public IP addresses, Internet, and VPN) are designed to be highly available and able to support the service SLA.

Azure Layer 7 Load Balancer for stateless VMware VMs

Users can put an Azure Layer 7 Load Balancer in front of the stateless web tier VMs running in the VMware environment to achieve high availability for the web tier.

Azure Regions

An Azure region is a set of data centers deployed within a latency-defined perimeter and connected through a dedicated regional low-latency network. For details, see Azure Regions.

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