agents should not need to run as root

[Robert Kukura]

When executing commands that require root privileges, they should use a root helper such as sudo. See nova.utils.execute(), which takes a run_as_root arg, and uses a configured root_helper. Not sure if this should be marked as a security vulnerability.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/5293

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/5293
Committed: http://github.com/openstack/quantum/commit/a06b316cb47369ef4a2c522f5240fa3f7f529135
Submitter: Jenkins
Branch: master

commit a06b316cb47369ef4a2c522f5240fa3f7f529135
Author: Bob Kukura <email address hidden>
Date: Tue Mar 13 17:23:06 2012 -0400

    Add root_helper to quantum agents.

    When running commands that require root privileges, the linuxbridge,
    openvswitch, and ryu agent now prepend the commands with the value of
    the root_helper config variable. This is set to "sudo" in the plugins'
    .ini files, allowing the agent to run as a non-root user with
    appropriate sudo privilidges.

    If root_helper is changed to "sudo quantum-rootwrap",
    then the command being run will be filtered against lists of each
    agent's valid commands in quantum/rootwrap. See
    http://wiki.openstack.org/Packager/Rootwrap for details.

    Fixes bug 948467.

    Change-Id: I549515068a4ce8ae480905ec5eaab6257445d0c3
    Signed-off-by: Bob Kukura <email address hidden>