Initialise oslo.privsep early in main

Any process using oslo.privsep should now initialise the library before
first use with things like the rootwrap command to use.

This should be done near the top of main() in any command that expects
to make privileged calls via oslo.privsep (eg: nova-compute, and not
nova-api).

See I3ea73e16b07a870629e7d69e897f2524d7068ae8 for the corresponding
change in oslo.privsep.

Change-Id: I3a52f762deb176fe9201b2a0f0da363057f8aaec
Depends-On: I52259e2023e277e8fd62be5df4fd7f799e9b36d7
Closes-Bug: #1592043

nova/cmd/compute.py

@@ -16,10 +16,12 @@
 
 """Starter script for Nova Compute."""
 
+import shlex
 import sys
 import traceback
 
 from oslo_log import log as logging
+from oslo_privsep import priv_context
 from oslo_reports import guru_meditation_report as gmr
 
 from nova.conductor import rpcapi as conductor_rpcapi
@@ -55,6 +57,7 @@ def __call__(self, *args, **kwargs):
 def main():
     config.parse_args(sys.argv)
     logging.setup(CONF, 'nova')
+    priv_context.init(root_helper=shlex.split(utils.get_root_helper()))
     utils.monkey_patch()
     objects.register_all()
 

requirements.txt

@@ -46,6 +46,7 @@ oslo.db>=4.1.0 # Apache-2.0
 oslo.rootwrap>=2.0.0 # Apache-2.0
 oslo.messaging>=5.2.0 # Apache-2.0
 oslo.policy>=1.9.0 # Apache-2.0
+oslo.privsep>=1.9.0  # Apache-2.0
 oslo.i18n>=2.1.0 # Apache-2.0
 oslo.service>=1.10.0 # Apache-2.0
 rfc3986>=0.2.0 # Apache-2.0