[ovs-discuss] Request: Debugging/troubleshooting OVN+Docker

[Ben Pfaff]

On Thu, Sep 29, 2016 at 10:19:18PM -0600, Scott Lowe wrote:
> Hi all, I was wondering if someone here could help me debug/troubleshoot an OVN+Docker environment that I've built for a demo in late October. I have three Ubuntu 14.04 nodes running Docker 1.11.2 and OVN 2.6 (built from source, including the kernel module). I've followed the instructions from INSTALL.Docker.md, and everything *seems* to work. However, I have no connectivity between two Docker containers attached to the same Docker network and running on two different hosts.
> 
> Where should I start to help figure out why connectivity isn't working? I see the logical switch in OVN (using `ovn-nbctl ls-list`), the logical ports (using `ovn-nbctl lsp-list`), and see the correct addresses on those ports (using `ovn-nbctl lsp-get-addresses`). What I *don't* see is any tunnel ports in `ovs-vsctl show`. I've verified the STT and Geneve kernel modules are loaded.
> 
> Any suggestions on what else to check?

Off the top of my head, here are some possible reasons "ovs-vsctl show"
might not show any tunnel ports on a given chassis:

    * ovn-controller isn't running.

    * ovn-controller can't connect to the southbound database, to read
      or write the Chassis table.  The ovn-controller log should
      indicate this.

    * ovn-controller can't connect to the ovs-vswitchd database, to add
      ports to the integration bridge.  The ovn-controller log should
      indicate that.

    * ovn-controller doesn't know what bridge is the integration bridge,
      or it has been told the wrong bridge.  From memory, I believe that
      it gets this configuration from the Open_vSwitch table in the
      ovs-vswitchd database.

    * The ovn-controllers don't know what IP address or tunneling
      protocol to advertise, so they can't tell this chassis how to
      connect to them.  From memory, I believe that ovn-controller gets
      this configuration from the Open_vSwitch table in the ovs-vswitchd
      database.

(The kernel modules don't actually matter for this purpose.  They'd only
come into play once the tunnel ports were added to the ovs-vswitchd
database.)