Using Ovirt Java SDK for VM automation .. I have to use payload mechanism as I am trying to using same user_data for all VM customization (Centos, Ubuntu and Windows) As push user_data content of size 8931 (String length) is it throwing 400 final_message: "The system is finally up, after $UPTIME seconds"] Size: [8931] org.ovirt.engine.sdk4.Error: HTTP response code is "400". HTTP response message is "Bad Request". at org.ovirt.engine.sdk4.internal.services.ServiceImpl.throwError(ServiceImpl.java:113) at org.ovirt.engine.sdk4.internal.services.ServiceImpl.checkFault(ServiceImpl.java:40) at org.ovirt.engine.sdk4.internal.services.VmServiceImpl$UpdateRequestImpl.send(VmServiceImpl.java:1543) at org.ovirt.engine.sdk4.internal.services.VmServiceImpl$UpdateRequestImpl.send(VmServiceImpl.java:1464) Sample code -------------- List<org.ovirt.engine.sdk4.types.File> files = new ArrayList<org.ovirt.engine.sdk4.types.File>(); String metadata = cloudinit.cloudInitMetaFile(map, vmname, vm.id()); String userdata = cloudinit.cloudInitUserData( map, vmname, pkglist); logger.info("Cloud-Init Script - user data [{}] Size: [{}]", userdata, userdata.length()); files.add(file().name("openstack/latest/meta_data.json").content(metadata).build()); files.add(file().name("openstack/latest/user_data").content(userdata).build()); if (networkdatafile != null && !networkdatafile.isEmpty()) { files.add(file().name("openstack/latest/network_data.json").content(networkdatafile).build()); contentnetworkdatafile = cloudinit.cloudNetworkConfigMetaData(map, "eth0" ); files.add(file().name("openstack/content/network-config").content(contentnetworkdatafile).build()); files.add(file().name("openstack/content/network-config").content(contentnetworkdatafile).build()); } vmService.update().vm(vm().payloads(payload().type(VmDeviceType.CDROM).files(files))).send();