Removes capacity disk(s) from a disk group.

    service_instance
        Service instance to the host or vCenter

    host_vsan_system
        ESXi host's VSAN system

    host_ref
        Reference to the ESXi host

    diskgroup
        The vsan.HostDiskMapping object representing the host's diskgroup from
        where the capacity needs to be removed

    capacity_disks
        List of vim.HostScsiDisk objects representing the capacity disks to be
        removed. Can be either ssd or non-ssd. There must be a minimum
        of 1 capacity disk in the list.

    data_evacuation
        Specifies whether to gracefully evacuate the data on the capacity disks
        before removing them from the disk group. Default value is True.

    hostname
        Name of ESXi host. Default value is None.

    host_vsan_system
        ESXi host's VSAN system. Default value is None.

def remove_capacity_from_diskgroup(service_instance, host_ref, diskgroup,
                                   capacity_disks, data_evacuation=True,
                                   hostname=None,
                                   host_vsan_system=None):
    '''
    Removes capacity disk(s) from a disk group.

    service_instance
        Service instance to the host or vCenter

    host_vsan_system
        ESXi host's VSAN system

    host_ref
        Reference to the ESXi host

    diskgroup
        The vsan.HostDiskMapping object representing the host's diskgroup from
        where the capacity needs to be removed

    capacity_disks
        List of vim.HostScsiDisk objects representing the capacity disks to be
        removed. Can be either ssd or non-ssd. There must be a minimum
        of 1 capacity disk in the list.

    data_evacuation
        Specifies whether to gracefully evacuate the data on the capacity disks
        before removing them from the disk group. Default value is True.

    hostname
        Name of ESXi host. Default value is None.

    host_vsan_system
        ESXi host's VSAN system. Default value is None.
    '''
    if not hostname:
        hostname = salt.utils.vmware.get_managed_object_name(host_ref)
    cache_disk = diskgroup.ssd
    cache_disk_id = cache_disk.canonicalName
    log.debug(
        'Removing capacity from disk group with cache disk \'%s\' on host \'%s\'',
        cache_disk_id, hostname
    )
    log.trace('capacity_disk_ids = %s',
              [c.canonicalName for c in capacity_disks])
    if not host_vsan_system:
        host_vsan_system = get_host_vsan_system(service_instance,
                                                host_ref, hostname)
    # Set to evacuate all data before removing the disks
    maint_spec = vim.HostMaintenanceSpec()
    maint_spec.vsanMode = vim.VsanHostDecommissionMode()
    if data_evacuation:
        maint_spec.vsanMode.objectAction = \
                vim.VsanHostDecommissionModeObjectAction.evacuateAllData
    else:
        maint_spec.vsanMode.objectAction = \
                vim.VsanHostDecommissionModeObjectAction.noAction
    try:
        task = host_vsan_system.RemoveDisk_Task(disk=capacity_disks,
                                                maintenanceSpec=maint_spec)
    except vim.fault.NoPermission as exc:
        log.exception(exc)
        raise VMwareApiError('Not enough permissions. Required privilege: '
                             '{0}'.format(exc.privilegeId))
    except vim.fault.VimFault as exc:
        log.exception(exc)
        raise VMwareApiError(exc.msg)
    except vmodl.RuntimeFault as exc:
        log.exception(exc)
        raise VMwareRuntimeError(exc.msg)
    salt.utils.vmware.wait_for_task(task, hostname, 'remove_capacity')
    return True