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===========
OVN Sandbox
===========

This tutorial shows you how to explore features using ``ovs-sandbox`` as a
simulated test environment.  It's assumed that you have an understanding of OVS
before going through this tutorial. Detail about OVN is covered in
ovn-architecture_, but this tutorial lets you quickly see it in action.

Getting Started
---------------

For some general information about ``ovs-sandbox``, see the "Getting Started"
section of :doc:`ovs-advanced`.

``ovs-sandbox`` does not include OVN support by default.  To enable OVN, you
must pass the ``--ovn`` flag.  For example, if running it straight from the OVS
git tree you would run::

    $ make sandbox SANDBOXFLAGS="--ovn"

Running the sandbox with OVN enabled does the following additional steps to the
environment:

1. Creates the ``OVN_Northbound`` and ``OVN_Southbound`` databases as described in
   `ovn-nb(5)`_ and `ovn-sb(5)`_.

2. Creates a backup server for ``OVN_Southbond`` database. Sandbox launch
   screen provides the instructions on accessing the backup database.  However
   access to the backup server is not required to go through the tutorial.

3. Creates the ``hardware_vtep`` database as described in `vtep(5)`_.

4. Runs the `ovn-northd(8)`_, `ovn-controller(8)`_, and
   `ovn-controller-vtep(8)`_ daemons.

5. Makes OVN and VTEP utilities available for use in the environment, including
   `vtep-ctl(8)`_, `ovn-nbctl(8)`_, and `ovn-sbctl(8)`_.

Using GDB
---------

GDB support is not required to go through the tutorial. See the "Using GDB"
section of :doc:`ovs-advanced` for more info. Additional flags exist for
launching the debugger for the OVN programs::

    --gdb-ovn-northd
    --gdb-ovn-controller
    --gdb-ovn-controller-vtep

Creating OVN Resources
----------------------

Once you have ``ovs-sandbox`` running with OVN enabled, you can start using OVN
utilities to create resources in OVN.  As an example, we will create an
environment that has two logical switches connected by a logical router.

Create the first logical switch with one port::

    $ ovn-nbctl ls-add sw0
    $ ovn-nbctl lsp-add sw0 sw0-port1
    $ ovn-nbctl lsp-set-addresses sw0-port1 "50:54:00:00:00:01 192.168.0.2"

Create the second logical switch with one port::

    $ ovn-nbctl ls-add sw1
    $ ovn-nbctl lsp-add sw1 sw1-port1
    $ ovn-nbctl lsp-set-addresses sw1-port1 "50:54:00:00:00:03 11.0.0.2"

Create the logical router and attach both logical switches::

    $ ovn-nbctl lr-add lr0
    $ ovn-nbctl lrp-add lr0 lrp0 00:00:00:00:ff:01 192.168.0.1/24
    $ ovn-nbctl lsp-add sw0 lrp0-attachment
    $ ovn-nbctl lsp-set-type lrp0-attachment router
    $ ovn-nbctl lsp-set-addresses lrp0-attachment 00:00:00:00:ff:01
    $ ovn-nbctl lsp-set-options lrp0-attachment router-port=lrp0
    $ ovn-nbctl lrp-add lr0 lrp1 00:00:00:00:ff:02 11.0.0.1/24
    $ ovn-nbctl lsp-add sw1 lrp1-attachment
    $ ovn-nbctl lsp-set-type lrp1-attachment router
    $ ovn-nbctl lsp-set-addresses lrp1-attachment 00:00:00:00:ff:02
    $ ovn-nbctl lsp-set-options lrp1-attachment router-port=lrp1

View a summary of OVN's current logical configuration::

    $ ovn-nbctl show
        switch 1396cf55-d176-4082-9a55-1c06cef626e4 (sw1)
            port lrp1-attachment
                addresses: ["00:00:00:00:ff:02"]
            port sw1-port1
                addresses: ["50:54:00:00:00:03 11.0.0.2"]
        switch 2c9d6d03-09fc-4e32-8da6-305f129b0d53 (sw0)
            port lrp0-attachment
                addresses: ["00:00:00:00:ff:01"]
            port sw0-port1
                addresses: ["50:54:00:00:00:01 192.168.0.2"]
        router f8377e8c-f75e-4fc8-8751-f3ea03c6dd98 (lr0)
            port lrp0
                mac: "00:00:00:00:ff:01"
                networks: ["192.168.0.1/24"]
            port lrp1
                mac: "00:00:00:00:ff:02"
                networks: ["11.0.0.1/24"]

The ``tutorial`` directory of the OVS source tree includes a script
that runs all of the commands for you::

    $ ./ovn-setup.sh

Using ovn-trace
---------------

Once you have configured resources in OVN, try using ``ovn-trace`` to see
how OVN would process a sample packet through its logical pipeline.

For example, we can trace an IP packet from ``sw0-port1`` to ``sw1-port1``.
The ``--minimal`` output shows each visible action performed on the packet,
which includes:

#. The logical router will decrement the IP TTL field.
#. The logical router will change the source and destination
   MAC addresses to reflect the next hop.
#. The packet will be output to ``sw1-port1``.

::

    $ ovn-trace --minimal sw0 'inport == "sw0-port1" \
    > && eth.src == 50:54:00:00:00:01 && ip4.src == 192.168.0.2 \
    > && eth.dst == 00:00:00:00:ff:01 && ip4.dst == 11.0.0.2 \
    > && ip.ttl == 64'

    # ip,reg14=0x1,vlan_tci=0x0000,dl_src=50:54:00:00:00:01,dl_dst=00:00:00:00:ff:01,nw_src=192.168.0.2,nw_dst=11.0.0.2,nw_proto=0,nw_tos=0,nw_ecn=0,nw_ttl=64
    ip.ttl--;
    eth.src = 00:00:00:00:ff:02;
    eth.dst = 50:54:00:00:00:03;
    output("sw1-port1");

The ``ovn-trace`` utility can also provide much more detail on how the packet
would be processed through OVN's logical pipeline, as well as correlate that
to OpenFlow flows programmed by ``ovn-controller``.  See the `ovn-trace(8)`_
man page for more detail.


.. _ovn-architecture: http://openvswitch.org/support/dist-docs/ovn-architecture.7.html
.. _ovn-nb(5): http://openvswitch.org/support/dist-docs/ovn-nb.5.html
.. _ovn-sb(5): http://openvswitch.org/support/dist-docs/ovn-sb.5.html
.. _vtep(5): http://openvswitch.org/support/dist-docs/vtep.5.html
.. _ovn-northd(8): http://openvswitch.org/support/dist-docs/ovn-northd.8.html
.. _ovn-controller(8): http://openvswitch.org/support/dist-docs/ovn-controller.8.html
.. _ovn-controller-vtep(8): http://openvswitch.org/support/dist-docs/ovn-controller-vtep.8.html
.. _vtep-ctl(8): http://openvswitch.org/support/dist-docs/vtep-ctl.8.html
.. _ovn-nbctl(8): http://openvswitch.org/support/dist-docs/ovn-nbctl.8.html
.. _ovn-sbctl(8): http://openvswitch.org/support/dist-docs/ovn-sbctl.8.html
.. _ovn-trace(8): http://openvswitch.org/support/dist-docs/ovn-trace.8.html
