redhat: allow dpdk to also run as non-root user

After this commit, users may start a dpdk-enabled ovs setup as a
non-root user.  This is accomplished by exporting the $HOME directory,
which dpdk uses to fill in it's semi-persistent RTE configuration.

This change may be a bit controversial since it modifies /dev/hugepages
as part of starting the ovs-vswitchd to set a hugetlbfs group
ownership.  This is used to enable writing to /dev/hugepages so that the
dpdk_init will successfully complete.  There is an alternate way of
accomplishing this - namely to initialize DPDK before dropping
privileges.  However, this would mean that if DPDK ever grows an uninit
/ reinit function, non-root ovs likely could never use it.

This does not change OvS+DPDK's SELinux requirements.  It still must be
disabled.

Signed-off-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: Russell Bryant <russell@ovn.org>

Documentation/intro/install/dpdk.rst

@@ -138,6 +138,13 @@ has to be configured with DPDK support (``--with-dpdk``).
 
 Additional information can be found in :doc:`general`.
 
+.. note::
+  If you are running using the Fedora or Red Hat package, the Open vSwitch
+  daemon will run as a non-root user.  This implies that you must have a
+  working IOMMU.  Visit the `RHEL README`__ for additional information.
+
+__ https://github.com/openvswitch/ovs/blob/master/rhel/README.RHEL.rst
+
 Setup
 -----
 

NEWS

@@ -80,6 +80,7 @@ v2.8.0 - xx xxx xxxx
        IETF NSH draft - https://datatracker.ietf.org/doc/draft-ietf-sfc-nsh/
    - Fedora Packaging:
      * OVN services are no longer restarted automatically after upgrade.
+     * ovs-vswitchd and ovsdb-server run as non-root users by default.
    - Add --cleanup option to command 'ovs-appctl exit' (see ovs-vswitchd(8)).
    - L3 tunneling:
      * Use new tunnel port option "packet_type" to configure L2 vs. L3.

rhel/README.RHEL.rst

@@ -337,6 +337,17 @@ running. All other commands where executed when Open vSwitch was successfully
 running.
 
 
+Non-root User Support
+-----------------------
+Fedora and RHEL support running the Open vSwitch daemons as a non-root user.
+By default, a fresh installation will create an *openvswitch* user, along
+with any additional support groups needed (such as *hugetlbfs* for DPDK
+support).
+
+This is controlled by modifying the ``OVS_USER_ID`` option.  Setting this
+to 'root:root', or commenting the variable out will revert this behavior.
+
+
 Reporting Bugs
 --------------
 

rhel/openvswitch-fedora.spec.in

@@ -95,6 +95,10 @@ Requires: openssl hostname iproute module-init-tools
 Requires(post): /usr/bin/getent
 Requires(post): /usr/sbin/useradd
 Requires(post): /usr/bin/sed
+%if %{with dpdk}
+Requires(post): /usr/sbin/usermod
+Requires(post): /usr/sbin/groupadd
+%endif
 Requires(post): systemd-units
 Requires(preun): systemd-units
 Requires(postun): systemd-units
@@ -379,6 +383,15 @@ if [ $1 -eq 1 ]; then
 
     sed -i 's:^#OVS_USER_ID=:OVS_USER_ID=:' /etc/sysconfig/openvswitch
 
+%if %{with dpdk}
+    getent group hugetlbfs >/dev/null || \
+        groupadd hugetlbfs
+    usermod -a -G hugetlbfs openvswitch
+    sed -i \
+        's@OVS_USER_ID="openvswitch:openvswitch"@OVS_USER_ID="openvswitch:hugetlbfs"@'\
+        /etc/sysconfig/openvswitch
+%endif
+
     # In the case of upgrade, this is not needed.
     chown -R openvswitch:openvswitch /etc/openvswitch
 fi

rhel/usr_lib_systemd_system_ovs-vswitchd.service.in

@@ -10,8 +10,13 @@ PartOf=openvswitch.service
 [Service]
 Type=forking
 Restart=on-failure
+Environment=HOME=/var/run/openvswitch
 EnvironmentFile=/etc/openvswitch/default.conf
 EnvironmentFile=-/etc/sysconfig/openvswitch
+@begin_dpdk@
+ExecStartPre=/usr/bin/chown :hugetlbfs /dev/hugepages
+ExecStartPre=/usr/bin/chmod 0775 /dev/hugepages
+@end_dpdk@
 ExecStart=/usr/share/openvswitch/scripts/ovs-ctl \
           --no-ovsdb-server --no-monitor --system-id=random \
           --ovs-user=${OVS_USER_ID} \