Hello,
at the end of the command 
hosted-engine --deploy

I get
[ INFO  ] TASK [Detect ovirt-hosted-engine-ha version]
[ INFO  ] changed: [localhost]
[ INFO  ] TASK [Set ha_version]
[ INFO  ] ok: [localhost]
[ INFO  ] TASK [Create configuration templates]
[ INFO  ] TASK [Create configuration archive]
[ INFO  ] changed: [localhost]
[ INFO  ] TASK [Create ovirt-hosted-engine-ha run directory]
[ INFO  ] changed: [localhost]
[ INFO  ] TASK [Copy configuration files to the right location on host]
[ INFO  ] TASK [Copy configuration archive to storage]
[ ERROR ]  [WARNING]: Failure using method (v2_runner_on_failed) in callback plugin
         
[ ERROR ] (<ansible.plugins.callback.1_otopi_json.CallbackModule object at 0x2dd7d90>):
         
[ ERROR ] 'ascii' codec can't encode character u'\u2018' in position 496: ordinal not in
         
[ ERROR ] range(128)
         
[ ERROR ] Failed to execute stage 'Closing up': Failed executing ansible-playbook
[ INFO  ] Stage: Clean up
[ INFO  ] Cleaning temporary resources
[ INFO  ] TASK [Gathering Facts]
[ INFO  ] ok: [localhost]
[ INFO  ] TASK [Remove local vm dir]
[ INFO  ] changed: [localhost]
[ INFO  ] Generating answer file '/var/lib/ovirt-hosted-engine-setup/answers/answers-20180129164431.conf'
[ INFO  ] Stage: Pre-termination
[ INFO  ] Stage: Termination
[ ERROR ] Hosted Engine deployment failed: this system is not reliable, please check the issue,fix and redeploy
          Log file is located at /var/log/ovirt-hosted-engine-setup/ovirt-hosted-engine-setup-20180129160956-a7itm9.log
[root@ov42 ~]#

Is there any known bug for this?

In log file I have:

2018-01-29 16:44:28,159+0100 ERROR otopi.ovirt_hosted_engine_setup.ansible_utils ansible_utils.run:173  [WARNING]: Failure using method (v2_runner_on_failed) in callback plugin

2018-01-29 16:44:28,160+0100 DEBUG otopi.plugins.otopi.dialog.human human.format:69 newline sent to logger
2018-01-29 16:44:28,160+0100 ERROR otopi.ovirt_hosted_engine_setup.ansible_utils ansible_utils.run:173 (<ansible.plugins.callback.1_otopi_json.CallbackModule object at 0x2dd7d90>):

2018-01-29 16:44:28,160+0100 DEBUG otopi.plugins.otopi.dialog.human human.format:69 newline sent to logger
2018-01-29 16:44:28,160+0100 ERROR otopi.ovirt_hosted_engine_setup.ansible_utils ansible_utils.run:173 'ascii' codec can't encode character u'\u2018' in position 496: ordinal not in

2018-01-29 16:44:28,161+0100 DEBUG otopi.plugins.otopi.dialog.human human.format:69 newline sent to logger
2018-01-29 16:44:28,161+0100 ERROR otopi.ovirt_hosted_engine_setup.ansible_utils ansible_utils.run:173 range(128)
2018-01-29 16:44:28,161+0100 DEBUG otopi.plugins.otopi.dialog.human human.format:69 newline sent to logger
2018-01-29 16:44:28,161+0100 DEBUG otopi.context context._executeMethod:143 method exception
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/otopi/context.py", line 133, in _executeMethod
    method['method']()
  File "/usr/share/ovirt-hosted-engine-setup/scripts/../plugins/gr-he-ansiblesetup/core/target_vm.py", line 193, in _closeup
    r = ah.run()
  File "/usr/lib/python2.7/site-packages/ovirt_hosted_engine_setup/ansible_utils.py", line 175, in run
    raise RuntimeError(_('Failed executing ansible-playbook'))
RuntimeError: Failed executing ansible-playbook
2018-01-29 16:44:28,162+0100 ERROR otopi.context context._executeMethod:152 Failed to execute stage 'Closing up': Failed executing ansible-playbook

I'm testing deploy of nested self hosted engine with HE on NFS.

Thanks,
Gianluca