I am getting error as User is not authorized to perform this action.I am using oVirt api to manually attach a disk and snapshot to another virtual machine.This the code i used.The API i followed is '<disk_attachment> <active>true</active> <bootable>false</bootable> <interface>virtio</interface> <disk id="a94106b7-d348-4088-aaa1-5dfc46dc094e"> <snapshot id="6ecbb953-c4fb-4294-9988-e7cd2bd9b038"/> <description>My disk</description> <format>cow</format> <name>mydisk</name> </disk> </disk_attachment> ============================== The php code i have tried is ... public function attachSnapshotandActivateDisk( ) { $data = array(); $xmlStr = '<disk_attachment> <active>true</active> <bootable>false</bootable> <interface>virtio</interface> <disk id="a94106b7-d348-4088-aaa1-5dfc46dc094e"> <snapshot id="6ecbb953-c4fb-4294-9988-e7cd2bd9b038"/> <description>My disk</description> <format>cow</format> <name>mydisk</name> </disk> </disk_attachment> '; $curlParam = array( "url" => "vms/74a1a99f-87d1-4444-b394-f90e4f29f51f/diskattachments", "method" => "POST", "data" => $xmlStr ); // $text = print_r($curlParam, true); //echo "<script>console.log( 'curl Parameter".json_encode($text)."');</script>"; $data = $this->processCurlRequest($curlParam, "vm-create"); // if instance update failed if ($data['status'] != 'success') { Common::ovirtLog(array( "requestParam" => $curlParam, "responseParam" => $data, )); } // show the output of print_r function as a string // $text = print_r($data, true); echo $data['message']; die; echo "<script type='text/javascript'> console.log('checking the attach snapshot activate disk function diskid=" . json_encode($data) . "') </script>"; //Detach the disk // $this->detachSnapshotDisk() ; return $data; } Please help me.