[ovs-discuss] Unable to add flows - Operation not permitted

[Seshadri, Usha]

Hello,

I am a newbie to OVS. I am trying to explore adding flows on the command line and running into 'Operation not permitted' errors.
Setup:

  1.  Docker image: Base CentOS 8 image + openvswitch binaries via dnf install
  2.  Image from step 1 deployed on OpenShift.
  3.  Startup OVS via ovs-ctl as a non-root user using 'ovs-ctl start' command on the CLI and the output from the command is as given below. I can see ovsdb-server and ovs-vswitchd are successfully running via the 'ps' command.
ovs-ctl start

/etc/openvswitch/conf.db does not exist ... (warning).
Creating empty database /etc/openvswitch/conf.db [  OK  ]
nice: cannot set niceness: Permission denied
Starting ovsdb-server [  OK  ]
system ID not configured, please use --system-id ... failed!
Configuring Open vSwitch system IDs [  OK  ]
nice: cannot set niceness: Permission denied
Starting ovs-vswitchd [  OK  ]
Enabling remote OVSDB managers [  OK  ]


  1.  I am trying to add flows by executing the following command on the CLI as a non-root user, but I see 'Operation not permitted' errors in the log file as provided below:
ovs-vsctl add-br br0
ovs-vsctl: Error detected while setting up 'br0'.  See ovs-vswitchd log for details.
ovs-vsctl: The default log directory is "/var/log/openvswitch".

cat /var/log/openvswitch/ovs-vswitchd.log
2021-05-05T14:44:19.191Z|00001|vlog|INFO|opened log file /var/log/openvswitch/ovs-vswitchd.log
2021-05-05T14:44:19.192Z|00002|vswitchd|ERR|mlockall failed: Cannot allocate memory
2021-05-05T14:44:19.193Z|00003|ovs_numa|INFO|Discovered 8 CPU cores on NUMA node 0
2021-05-05T14:44:19.193Z|00004|ovs_numa|INFO|Discovered 1 NUMA nodes and 8 CPU cores
2021-05-05T14:44:19.194Z|00005|reconnect|INFO|unix:/var/run/openvswitch/db.sock: connecting...
2021-05-05T14:44:19.195Z|00006|netlink_socket|INFO|netlink: could not enable listening to all nsid (Operation not permitted)
2021-05-05T14:44:19.196Z|00007|reconnect|INFO|unix:/var/run/openvswitch/db.sock: connected
2021-05-05T14:44:19.199Z|00008|dpif_netlink|INFO|The kernel module does not support meters.
2021-05-05T14:44:19.201Z|00009|bridge|INFO|ovs-vswitchd (Open vSwitch) 2.12.0
2021-05-05T16:05:15.276Z|00010|memory|INFO|2964 kB peak resident set size after 4856.1 seconds
2021-05-05T16:05:15.277Z|00011|dpif|WARN|failed to create datapath ovs-system: Operation not permitted
2021-05-05T16:05:15.278Z|00012|ofproto_dpif|ERR|failed to open datapath of type system: Operation not permitted
2021-05-05T16:05:15.278Z|00013|ofproto|ERR|failed to open datapath br0: Operation not permitted
2021-05-05T16:05:15.278Z|00014|bridge|ERR|failed to create bridge br0: Operation not permitted


  1.  Running the command again says the bridge already exists.

ovs-vsctl add-br br0
ovs-vsctl: cannot create a bridge named br0 because a bridge named br0 already exists

It appears I may be running into permissions issue. The owner + group permissions are identical, owned by root. The user in OpenShift belongs to the root group. Does OVS need to run as root? Any help with this is greatly appreciated.


Thanks,
Usha

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