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MoveClusterGroupEx function (clusapi.h)

  • Article

Extends the existing MoveClusterGroup method with the addition of flags and a buffer. The flags control the behavior of the cluster failover policy, and the input buffer enables the client to send special instructions to the resources in the group.

Syntax

DWORD MoveClusterGroupEx(
  [in]           HGROUP hGroup,
  [in, optional] HNODE  hDestinationNode,
  [in]           DWORD  dwMoveFlags,
  [in, optional] PBYTE  lpInBuffer,
  [in]           DWORD  cbInBufferSize
);

Parameters

[in] hGroup

The handle to a cluster group.

[in, optional] hDestinationNode

The handle to a cluster node, indicating the node to which the group should be moved. This parameter is optional. If left NULL, the cluster will move the group to the most suitable node, according to failover policies configured for the cluster and for this particular group.

[in] dwMoveFlags

A bitwise combination of the flags that influence the failover policy with respect to this move operation.

CLUSAPI_GROUP_MOVE_IGNORE_RESOURCE_STATUS (0x00000001)

Forces the group move even if a resource has indicated that it should be "locked" in its current state on the current node, and terminates the resource if necessary.

CLUSAPI_GROUP_MOVE_RETURN_TO_SOURCE_NODE_ON_ERROR (0x00000002)

If the group fails to reach its persistent state on the destination node (whether specified with hDestinationNode or chosen by the cluster), returns the group to the source node and brings it to its persistent state there.

CLUSAPI_GROUP_MOVE_QUEUE_ENABLED (0x00000004)

If a resource DLL in the group indicates that the move is not possible at this time but may be possible in the near future, queues this move in the cluster service and continues retrying, when deemed appropriate, until either the move operation completes or is cancelled by the client.

CLUSAPI_GROUP_MOVE_HIGH_PRIORITY_START (0x00000008)

Brings this group to its persistent state on the destination node as soon as possible without regard to implementation-specific policies that govern the ordering and/or prioritization of bringing groups to their persistent states.

CLUSAPI_GROUP_MOVE_FAILBACK (0x00000010)

Reserved.

[in, optional] lpInBuffer

A property list that contains move operation instructions for specific resources within the group. The instructions are contained in property values. Resources in the group search the property list for property names that they support for move operations and then interpret the instructions in the associated property value. The properties supported by a resource in a MoveClusterGroupEx operation are not related to the private properties associated with a resource.

[in] cbInBufferSize

The size of lpInBuffer, in bytes.

Return value

MoveClusterGroupEx returns ERROR_IO_PENDING if the move command has been accepted and is in progress. MoveClusterGroupEx returns a nonzero error code if the move command was rejected immediately with no changes to group state. For instance, this would happen if hDestinationNode is not Up at the time of the move request.

Remarks

MoveClusterGroupEx fails immediately with error ERROR_CLUSTER_RESOURCE_LOCKED_STATUS if the CLUSAPI_GROUP_MOVE_IGNORE_RESOURCE_STATUS flag is not set and any resource in the group is online and has indicated that it is "locked" in its current state.

After MoveClusterGroupEx returns ERROR_IO_PENDING, there are a number of possible outcomes, including:

  • The move operation could succeed, and the group could reach its persistent state on the target node.
  • The move operation could fail, in that the group cannot reach its persistent state on the target node. If dwMoveFlags does not include CLUSAPI_GROUP_MOVE_RETURN_TO_SOURCE_NODE_ON_ERROR, then the cluster will take appropriate action (according to configured policies) to bring the group to its persistent state, perhaps on other nodes in the cluster. If dwMoveFlags includes CLUSAPI_GROUP_MOVE_RETURN_TO_SOURCE_NODE_ON_ERROR, then the cluster will attempt to bring the group to its persistent state on the source node. If this fails, then the cluster will take appropriate action (according to configured policies) to bring the group to its persistent state, perhaps on other nodes in the cluster.
  • The move operation could be queued if a resource indicates that it cannot move immediately and the CLUSAPI_GROUP_MOVE_QUEUE_ENABLED flag is set.
  • The move operation could be rejected by a resource in the group, thus returning the group to its persistent state on the source node without incrementing any failure counts or triggering any failure policies. This cannot occur if the CLUSAPI_GROUP_MOVE_IGNORE_RESOURCE_STATUS flag is set.
For a live migration of a virtual machine, perform these steps:
  1. In the dwMoveFlags parameter, set the CLUSAPI_GROUP_MOVE_RETURN_TO_SOURCE_NODE_ON_ERROR, CLUSAPI_GROUP_MOVE_QUEUE_ENABLED, and CLUSAPI_GROUP_MOVE_HIGH_PRIORITY_START flags.
  2. In the lpInBuffer parameter, add to the property list a resource type named "Virtual Machine" or "Virtual Machine Configuration" that specifies a CLUSTER_PROPERTY_FORMAT enumeration value of CLUSPROP_FORMAT_DWORD (which represents the property's data format) and a property value of VmResdllContextLiveMigration (from the VM_RESDLL_CONTEXT enumeration of possible virtual machine actions).
MoveClusterGroupEx requires that the client be granted Full access in the cluster security descriptor.

Examples

#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <ClusAPI.h>


#define DemoResDllTypeName L"dummy"
#define DemoGroupName L"DemoGroup"


int __cdecl main( void )
{
    HCLUSTER hCluster= NULL;
    HGROUP hGroup = NULL;
    DWORD error = 0;

    hCluster = OpenCluster( NULL );
    if ( hCluster == NULL )
    {
        error = GetLastError();
        wprintf( L"Failed to open cluster: 0x%x\n", error );
        goto Cleanup;
    }

    hGroup = OpenClusterGroup( hCluster, DemoGroupName );
    if ( hGroup == NULL )
    {
        error = GetLastError();
        wprintf( L"Failed to open cluster group " DemoGroupName L": 0x%x\n", error );
        goto Cleanup;
    }


    // Move Group example
    error = MoveClusterGroupEx( hGroup,
                                NULL,
                                CLUSAPI_GROUP_MOVE_RETURN_TO_SOURCE_NODE_ON_ERROR | CLUSAPI_GROUP_MOVE_IGNORE_RESOURCE_STATUS,
                                NULL,
                                0);

    if ( error == ERROR_IO_PENDING  )
    {
        wprintf( L"Group move pending" DemoGroupName L": 0x%x\n", error );
        error = ERROR_SUCCESS;
    }
    else if ( error != ERROR_SUCCESS)
    {
        wprintf( L"Failed to move group" DemoGroupName L": 0x%x\n", error );
    }
    else 
    {
        wprintf( L"Group move completed" DemoGroupName L": 0x%x\n");
    }

Cleanup:

    if ( hGroup != NULL )
    {
        CloseClusterGroup( hGroup );
        hGroup = NULL;
    }
    if ( hCluster != NULL )
    {
        CloseCluster( hCluster );
        hCluster = NULL;
    }

    return (int)error;
}

Requirements

Requirement Value
Minimum supported client None supported
Minimum supported server Windows Server 2012
Target Platform Windows
Header clusapi.h
Library ClusAPI.lib
DLL ClusAPI.dll