Try with 'hosted-engine --vm-conf' options.
Is it just a guess or did you try and worked with this parameter?
[root@novirt2 ovirt-hosted-engine]# hosted-engine --vm-start --help
Usage: /sbin/hosted-engine --vm-start
Start the engine VM on this host.
Available only after deployment has completed.
--vm-conf=<file>
Load an alternative vm.conf file as a recovery action.
[root@novirt2 ovirt-hosted-engine]#
But hwo to give my vm.conf?
Eg if I untar the vm.conf on shared storage
# tar -C /tmp/q -xvf 2e0f414c-2589-4545-a0a4-3bfed24ef3fc
and then modify vm.conf removing the +tsx-ctrl
# hosted-engine --vm-start --vm-conf=/tmp/q/vm.conf
VM exists and is Down, cleaning up and restarting
Command VM.create with args {'vmID': '22082519-70bb-476f-a373-45c2d402a870', 'vmParams': {'vmId': '22082519-70bb-476f-a373-45c2d402a870', 'memSize': '16384', 'display': 'vnc', 'vmName': 'HostedEngine', 'spiceSecureChannels': 'smain,sdisplay,sinputs,scursor,splayback,srecord,ssmartcard,susbredir', 'smp': '2', 'maxVCpus': '8', 'cpuType': 'Cascadelake-Server,+md-clear,+mds-no,-hle,-rtm,+arch-capabilities', 'emulatedMachine': '', 'devices': [{'index': '2', 'iface': 'ide', 'address': {'controller': '0', 'target': '0', 'unit': '0', 'bus': '1', 'type': 'drive'}, 'specParams': {}, 'readonly': 'true', 'deviceId': '', 'path': '', 'device': 'cdrom', 'shared': 'false', 'type': 'disk'}, {'index': '0', 'iface': 'virtio', 'format': 'raw', 'poolID': '00000000-0000-0000-0000-000000000000', 'volumeID': '15f606c1-757f-44a8-adc7-85e75ff02944', 'imageID': '8c2b8355-ba2d-4ffa-8055-0034d56f0dd7', 'specParams': {}, 'readonly': 'false', 'domainID': '7c9397f5-859b-4fba-bcc5-4ecbd454a189', 'optional': 'false', 'deviceId': '15f606c1-757f-44a8-adc7-85e75ff02944', 'address': {'bus': '0x00', 'slot': '0x06', 'domain': '0x0000', 'type': 'pci', 'function': '0x0'}, 'device': 'disk', 'shared': 'exclusive', 'propagateErrors': 'off', 'type': 'disk', 'bootOrder': '1'}, {'device': 'scsi', 'model': 'virtio-scsi', 'type': 'controller'}, {'nicModel': 'pv', 'macAddr': '00:16:3e:68:a9:cc', 'linkActive': 'true', 'network': 'ovirtmgmt', 'specParams': {}, 'deviceId': '', 'address': {'bus': '0x00', 'slot': '0x03', 'domain': '0x0000', 'type': 'pci', 'function': '0x0'}, 'device': 'bridge', 'type': 'interface'}, {'device': 'console', 'type': 'console'}, {'device': 'vga', 'alias': 'video0', 'type': 'video'}, {'device': 'vnc', 'type': 'graphics'}, {'device': 'virtio', 'specParams': {'source': 'urandom'}, 'model': 'virtio', 'type': 'rng'}]}} failed:
(code=100, message=General Exception: ("'xml'",))
VM failed to launch
[root@novirt2 530490b0-935e-46a8-84f6-6cd6618c6f0d]#
In vdsm.log
2020-04-20 17:16:51,401+0200 ERROR (jsonrpc/3) [api] FINISH create error='xml' (api:134)
Traceback (most recent call last):
File "/usr/lib/python3.6/site-packages/vdsm/common/api.py", line 124, in method
ret = func(*args, **kwargs)
File "/usr/lib/python3.6/site-packages/vdsm/API.py", line 190, in create
xml = vmParams.get('_srcDomXML') or vmParams['xml']
KeyError: 'xml'
2020-04-20 17:16:51,402+0200 INFO (jsonrpc/3) [api.virt] FINISH create return={'status': {'code': 100, 'message': 'General Exception: ("\'xml\'",)'}} from=::1,44384, vmId=22082519-70bb-476f-a373-45c2d402a870 (api:54)
2020-04-20 17:16:51,402+0200 INFO (jsonrpc/3) [jsonrpc.JsonRpcServer] RPC call VM.create failed (error 100) in 0.00 seconds (__init__:312)
2020-04-20 17:16:51,598+0200 INFO (jsonrpc/4) [jsonrpc.JsonRpcServer] RPC call Host.ping2 succeeded in 0.00 seconds (__init__:312)
and the same if I leave vm.conf unmodified....
Gianluca