At a client site, I have 6 nodes running Openstack Mitaka on top of RHEL 7.2. After rebooting one node, however, the networking configs in /etc/sysconfig/network-scripts were not being loaded (specifically, the OVS bridges necessary for Openstack to run, i.e. br-ex, br-int). When I attempted to manually load the network settings with
systemctl start network
I was told that the systemd unit file network.service does not exist! This file is normally generated automatically by systemd-sysv-generator at boot from legacy SystemV scripts in /etc/init.d/ and written to /run/systemd/generator.late/network, but for some reason this was not happening.
Because RHEL 7.2 was not reading my network config files, I decided to manually create the OVS bridges using the following commands:
ovs-vsctl add-br br-ex
ip link set br-ex up
ovs-vsctl add-port br-ex eno1
To use OpenVSwitch, however, the systemd's openvswitch.service must be running. When I tried to invoke the service using systemctl start openvswitch, I got the following error:
DBus.Error.AccessDenied: An SELinux policy prevents this sender from sending this message to this recipient
Also the journalctl log showed tons of auditd errors that continued to print every 3 seconds or so.
It turns out that this is a permissions problem on /! According to Redhat, the proper permissions on the root partition is 555, or r-x r-x r-x. After changing the permissions and rebooting, I no longer get the DBus.Error.AccessDenied error message. I don't know why the perm's on / have to be set as 555 (on a personal Archlinux installation without SELINUX, the perms on / are 755 rwx r-x r-x). Furthermore I don't know how the perms got changed to 555. I checked the history log on the affected nodes and there is no record of anyone changing permissions on the root partition.
References:
https://access.redhat.com/solutions/1990203 (you must register in order to access this Knowledge Base solution)
