Creating Failover Cluster Instances

To implement high availability for a server application or any other resource normally accessed by a computer name, you should configure the resource to run in the context of a failover cluster instance. This task can be left to administrators, or you can write code to create a failover cluster instance specific to the needs of your application.

To create a failover cluster instance

1. Create a group (see Creating Groups) that contains an IP Address resource, an IPv6 Address resource, and/or an IPv6 Tunnel Address resource, a Network Name resource, your resource, and any other resources that must be in the same group.

2. Call AddClusterResourceDependency to establish the following dependencies:

   1. Add the IP Address resource, IPv6 Address resource, and/or IPv6 Tunnel Address resource as dependencies of the Network Name resource.
   2. Add either the IP Address resource, IPv6 Address resource, and/or IPv6 Tunnel Address resource or the Network Name resource as a dependencies of your resource.
   3. Add other dependencies based on the requirements of your resource.

3. Configure all required and other properties. See Configuring Resources.

Example Code

The following code demonstrates the creation of a "bare bones" failover cluster instance—a group with an IP Address resource and a Network Name resource. This example calls other example functions presented elsewhere in this documentation. To locate these example functions, see the Index of Examples.

#include <windows.h>

//////////////////////////////////////////////////////////////////////

#include "ClusDocEx.h"

//////////////////////////////////////////////////////////////////////

#ifndef CLUSDOCEX_GRPCREATEVIRTUALSERVER_CPP
#define CLUSDOCEX_GRPCREATEVIRTUALSERVER_CPP
//--------------------------------------------------------------------
//  ClusDocEx_GrpCreateVirtualServer
//
//  Configures a group as a failover cluster instance.
//
//  Arguments:
//    IN HCLUSTER hCluster         Cluster handle.
//    IN LPWSTR   lpszGroupName    Name of the new instance.
//    IN LPWSTR   lpszIPResName    Name of the IP Address resource
//    IN LPWSTR   lpszNetResName   Name of the Network Name resource
//    IN LPWSTR   lpszAddress      IP address of the instance.
//    IN LPWSTR   lpszNetworkName  Network name of the instance.
//    IN LPWSTR   lpszSubnetMask   Subnet mask for the instance. 
//
//  Return Value:
//     Group handle (if successful) or NULL (if unsuccessful)
//--------------------------------------------------------------------
HGROUP ClusDocEx_GrpCreateVirtualServer
(
  IN HCLUSTER hCluster,
  IN LPWSTR   lpszGroupName,
  IN LPWSTR   lpszIPResName,
  IN LPWSTR   lpszNetResName,
  IN LPWSTR   lpszIPAddress,
  IN LPWSTR   lpszNetworkName,
  IN LPWSTR   lpszSubnetMask
)
{
  HGROUP    hGroup       = NULL;
  HRESOURCE hIPAddress   = NULL;
  HRESOURCE hNetworkName = NULL;
  DWORD     dwResult     = ERROR_SUCCESS;


//  Create the group.

  hGroup = CreateClusterGroup( hCluster, lpszGroupName );
    
  if( hGroup == NULL )
   {
    dwResult = GetLastError();
    goto endf;
   }

  if( hGroup != NULL )
   {

    //  Create the IP Address resource.

    hIPAddress = ClusDocEx_ResCreateIPAddress( hGroup,
                                               lpszIPResName,
                                               lpszIPAddress,
                                               lpszNetworkName,
                                               lpszSubnetMask );

    if( hIPAddress == NULL )
     {
      dwResult = GetLastError();
      goto endf;
     }

    //  Create the Network Name resource.

    hNetworkName = ClusDocEx_ResCreateNetworkName( hGroup,
                                                   hIPAddress,
                                                   lpszNetResName,
                                                   lpszNetworkName );

    if( hNetworkName == NULL )
     {
      dwResult = GetLastError();
      goto endf;
     }
   }

endf:

  if( dwResult != ERROR_SUCCESS )
   {
    if( hNetworkName != NULL )
     {
      DeleteClusterResource( hNetworkName );

      //  Must always close handles after deletion. 

      CloseClusterResource( hNetworkName );
      hNetworkName = NULL;
     }

    if( hIPAddress != NULL )
     {
      DeleteClusterResource( hIPAddress);
      CloseClusterResource( hIPAddress);
      hIPAddress = NULL;
     }

    if( hGroup != NULL )
     {
      DeleteClusterGroup( hGroup );
      CloseClusterGroup( hGroup );
      hGroup = NULL;
     }
   }


  //  Close resource handles. 

  if( hNetworkName != NULL )
   {
    CloseClusterResource( hNetworkName );
   }
  if( hIPAddress != NULL )
   {
    CloseClusterResource( hIPAddress);
   }
    

  SetLastError( dwResult );

  return hGroup;
 }
//  end ClusDocEx_GrpCreateVirtualServer
//--------------------------------------------------------------------
#endif