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RoleEnvironmentTopologyChange Class

Represents a change to the topology of a role.

Namespace: Microsoft.WindowsAzure.ServiceRuntime
Assembly: Microsoft.WindowsAzure.ServiceRuntime (in Microsoft.WindowsAzure.ServiceRuntime.dll)
VB
C#
C++
F#
JScript
PowerShell 
Public Class RoleEnvironmentTopologyChange
	Inherits RoleEnvironmentChange
	Implements IEquatable(Of RoleEnvironmentTopologyChange)
J#

The topology refers to the number of instances and the number of endpoints that are defined for a role. The number of instances for a role in a hosted service is configured in the ServiceConfiguration.cscfg file. The following XML example shows the configuration of the Instances element:

XML 

<?xml version-"1.0" encoding="utf-8"?>
<ServiceConfiguration name="MyService" xmln=http://schema.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration osFamily="1" osVersion="*">
   <Role name="WebRole1">
      <Instances count="2" />
   </Role>
</ServiceConfiguration>

For more information about defining the service model for a hosted service, see Setting Up a Hosted Service for Windows Azure.

noteNote
At least one internal endpoint must be defined for a role in order to raise RoleEnvironmentTopologyChange. For more information about defining internal endpoints, see How to Define Internal Endpoints for a Role.

ImportantImportant
It is highly recommended that you configure the hosted service to run at least two instances of the role. When you deploy two or more role instances in different fault and upgrade domains, your Internet facing roles have external connectivity at least 99.95% of the time. For more information, see Service Level Agreements. For more information about changing the topology of a role, see How to Scale Applications by Increasing or Decreasing the Number of Role Instances.


System.Object
   Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironmentChange
    Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironmentTopologyChange
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Development Platforms

Windows Vista, Windows 7 and Windows Server 2008

Target Platforms