ppc64_cpu check is not suitable on ppc64le VM

[huhaoran]

on ppc64le VM, when run "sudo ppc64_cpu --smt=off" may have error code 255

root@juju-7d5138-11:/var/log/juju# sudo ppc64_cpu --smt=off
Machine is not SMT capable
root@juju-7d5138-11:/var/log/juju# echo $?
255

log snapshot:
2016-09-27 06:33:47 INFO juju-log CPU architecture: ppc64le
2016-09-27 06:33:47 INFO config-changed Machine is not SMT capable
2016-09-27 06:33:47 INFO config-changed Traceback (most recent call last):
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/config-changed", line 500, in <module>
2016-09-27 06:33:47 INFO config-changed main()
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/config-changed", line 493, in main
2016-09-27 06:33:47 INFO config-changed hooks.execute(sys.argv)
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/core/hookenv.py", line 715, in execute
2016-09-27 06:33:47 INFO config-changed self._hooks[hook_name]()
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 1810, in wrapped_f
2016-09-27 06:33:47 INFO config-changed restart_functions)
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/core/host.py", line 526, in restart_on_change_helper
2016-09-27 06:33:47 INFO config-changed r = lambda_f()
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 1809, in <lambda>
2016-09-27 06:33:47 INFO config-changed (lambda: f(*args, **kwargs)), restart_map, stopstart,
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/contrib/hardening/harden.py", line 79, in _harden_inner2
2016-09-27 06:33:47 INFO config-changed return f(*args, **kwargs)
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/config-changed", line 193, in config_changed
2016-09-27 06:33:47 INFO config-changed set_ppc64_cpu_smt_state('off')
2016-09-27 06:33:47 INFO config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/nova_compute_utils.py", line 491, in set_ppc64_cpu_smt_state
2016-09-27 06:33:47 INFO config-changed current_smt_state = check_output(['ppc64_cpu', '--smt'])
2016-09-27 06:33:47 INFO config-changed File "/usr/lib/python2.7/subprocess.py", line 574, in check_output

There may be an improvement on nova_compute_utils.py

[huhaoran (vennie1988)]

If this charm is installed in a bare mental ppc64el machine, this charm do not have this issue. This charm has issues in ppc64le vm.

[Aurelien Lourot (aurelien-lourot)]

This just hit me when trying to deploy openstack-on-lxd ( https://github.com/openstack-charmers/openstack-on-lxd/blob/master/bundle-bionic-queens.yaml ) on a ppc64el metal machine.

```
nova-compute/0* error idle 20 10.106.108.10 hook failed: "config-changed"
```

```
2019-11-29 22:05:21 WARNING juju-log Failed to set ppc64_cpu smt state: off
2019-11-29 22:05:21 DEBUG config-changed Traceback (most recent call last):
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/config-changed", line 761, in <module>
2019-11-29 22:05:21 DEBUG config-changed main()
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/config-changed", line 754, in main
2019-11-29 22:05:21 DEBUG config-changed hooks.execute(sys.argv)
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/core/hookenv.py", line 914, in execute
2019-11-29 22:05:21 DEBUG config-changed self._hooks[hook_name]()
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 1568, in wrapped_f
2019-11-29 22:05:21 DEBUG config-changed stopstart, restart_functions)
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/core/host.py", line 741, in restart_on_change_helper
2019-11-29 22:05:21 DEBUG config-changed r = lambda_f()
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 1567, in <lambda>
2019-11-29 22:05:21 DEBUG config-changed (lambda: f(*args, **kwargs)), __restart_map_cache['cache'],
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/charmhelpers/contrib/hardening/harden.py", line 93, in _harden_inner2
2019-11-29 22:05:21 DEBUG config-changed return f(*args, **kwargs)
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/config-changed", line 251, in config_changed
2019-11-29 22:05:21 DEBUG config-changed set_ppc64_cpu_smt_state('off')
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/nova_compute_utils.py", line 595, in set_ppc64_cpu_smt_state
2019-11-29 22:05:21 DEBUG config-changed raise e
2019-11-29 22:05:21 DEBUG config-changed File "/var/lib/juju/agents/unit-nova-compute-0/charm/hooks/nova_compute_utils.py", line 589, in set_ppc64_cpu_smt_state
2019-11-29 22:05:21 DEBUG config-changed check_output(cmd)
2019-11-29 22:05:21 DEBUG config-changed File "/usr/lib/python3.6/subprocess.py", line 356, in check_output
2019-11-29 22:05:21 DEBUG config-changed **kwargs).stdout
2019-11-29 22:05:21 DEBUG config-changed File "/usr/lib/python3.6/subprocess.py", line 438, in run
2019-11-29 22:05:21 DEBUG config-changed output=stdout, stderr=stderr)
2019-11-29 22:05:21 DEBUG config-changed subprocess.CalledProcessError: Command '['ppc64_cpu', '--smt=off']' returned non-zero exit st...