Comment 2 for bug 1645918

with local.conf of devstack as below;

[[local|localrc]]
DATABASE_PASSWORD=password
RABBIT_PASSWORD=password
SERVICE_TOKEN=password
SERVICE_PASSWORD=password
ADMIN_PASSWORD=password
# magnum requires the following to be set correctly
PUBLIC_INTERFACE=enp0s3
HOST_IP=10.0.2.15

NOVA_BRANCH=stable/mitaka

# Enable barbican service and use it to store TLS certificates
# For details http://docs.openstack.org/developer/magnum/dev/tls.html
enable_plugin barbican https://git.openstack.org/openstack/barbican

enable_plugin heat https://git.openstack.org/openstack/heat

# Enable magnum plugin after dependent plugins
enable_plugin magnum https://git.openstack.org/openstack/magnum

# Optional: uncomment to enable the Magnum UI plugin in Horizon
#enable_plugin magnum-ui https://github.com/openstack/magnum-ui

VOLUME_BACKING_FILE_SIZE=20G

I get below error when run stack.sh

Ignoring watchdog: markers 'python_version == "3.4"' don't match your environment
Ignoring watchdog: markers 'python_version == "3.5"' don't match your environment
Obtaining file:///opt/stack/nova
Exception:
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/local/lib/python2.7/dist-packages/pip/commands/install.py", line 335, in run
    wb.build(autobuilding=True)
  File "/usr/local/lib/python2.7/dist-packages/pip/wheel.py", line 749, in build
    self.requirement_set.prepare_files(self.finder)
  File "/usr/local/lib/python2.7/dist-packages/pip/req/req_set.py", line 380, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "/usr/local/lib/python2.7/dist-packages/pip/req/req_set.py", line 521, in _prepare_file
    req_to_install.check_if_exists()
  File "/usr/local/lib/python2.7/dist-packages/pip/req/req_install.py", line 1036, in check_if_exists
    self.req.name
  File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 558, in get_distribution
    dist = get_provider(dist)
  File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 432, in get_provider
    return working_set.find(moduleOrReq) or require(str(moduleOrReq))[0]
  File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 968, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 859, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
ContextualVersionConflict: (psutil 5.1.3 (/usr/local/lib/python2.7/dist-packages), Requirement.parse('psutil<2.0.0,>=1.1.1'), set(['nova']))

Not sure it is the bug of openstack-requirments or bug of the devstack.