ovs-sim: Convert documentation to RST format.

Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Justin Pettit <jpettit@ovn.org>

2 files changed, 225 insertions, 0 deletions

diff --git a/Documentation/ref/index.rst b/Documentation/ref/index.rst
index 3d511decb..29183af62 100644
--- a/Documentation/ref/index.rst
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@@ -39,6 +39,7 @@ time:
 .. toctree::
    :maxdepth: 3
 
+   ovs-sim.1
    ovs-test.8
    ovs-vlan-test.8
    ovsdb-server.7
diff --git a/Documentation/ref/ovs-sim.1.rst b/Documentation/ref/ovs-sim.1.rst
new file mode 100644
index 000000000..12e7f63f7
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+++ b/Documentation/ref/ovs-sim.1.rst
@@ -0,0 +1,224 @@
+=======
+ovs-sim
+=======
+
+Synopsis
+========
+
+``ovs-sim`` [*option*]... [*script*]...
+
+Description
+===========
+
+``ovs-sim`` provides a convenient environment for running one or more Open
+vSwitch instances and related software in a sandboxed simulation environment.
+
+To use ``ovs-sim``, first build Open vSwitch, then invoke it directly from the
+build directory, e.g.::
+
+    git clone https://github.com/openvswitch/ovs.git
+    cd ovs
+    ./configure
+    make
+    utilities/ovs-sim
+
+When invoked in the most ordinary way as shown above, ovs-sim does  the
+following:
+
+1. Creates a directory ``sandbox`` as a subdirectory of the current
+   directory (first destroying such a directory if it already exists)
+   and makes it the current directory.
+
+2. Installs all of the Open vSwitch manpages into a ``man``
+   subdirectory of sandbox and adjusts the ``MANPATH`` environment
+   variable so that ``man`` and other manpage viewers can find them.
+
+3. Creates a simulated Open vSwitch named ``main`` and sets it up as the
+   default target for OVS commands, as if the following ``ovs-sim``
+   commands had been run::
+
+            sim_add main
+            as main
+
+  See `Commands`_, below, for an explanation.
+
+4. Runs  any  scripts  specified on the command line (see `Options`_,
+   below). The scripts can use arbitrary Bash  syntax,  plus  the
+   additional commands described under `Commands`_, below.
+
+5. If no scripts were specified, or if ``-i`` or ``--interactive`` was
+   specified, invokes an interactive Bash subshell. The user can use
+   arbitrary Bash commands, plus the additional commands described under
+   `Commands`_, below.
+
+``ovs-sim`` and the sandbox environment that it creates does not require
+superuser or other special privileges.  Generally, it should not be run with
+such privileges.
+
+Options
+=======
+
+.. program: ovs-sim
+
+*script*
+    Runs *script*, which should be a Bash script, within a subshell
+    after initializing.  If multiple script arguments are given, then
+    they are run in the order given.  If any script exits with a
+    nonzero exit code, then ``ovs-sim`` exits immediately with the
+    same exit code.
+
+``-i`` or ``--interactive``
+    By default, if any script is specified, ``ovs-sim`` exits as soon as the
+    scripts finish executing. With this option, or if no scripts are specified,
+    ``ovs-sim`` instead starts an interactive Bash session.
+
+Commands
+========
+
+Scripts and interactive usage may use the following commands
+implemented by ``ovs-sim``.  They are implemented as Bash shell functions
+exported to subshells.
+
+Basic Commands
+--------------
+
+These  are  the  basic commands for working with sandboxed Open vSwitch
+instances.
+
+``sim_add`` *sandbox*
+    Starts a new simulated Open vSwitch instance named *sandbox*.
+    Files related to the instance, such as logs, databases, sockets,
+    and pidfiles, are created in a subdirectory also named
+    *sandbox*. Afterward, the ``as`` command (see below) can be used
+    to run Open vSwitch utilities in the context of the new sandbox.
+
+    The new sandbox starts out without any bridges. Use ``ovs-vsctl``
+    in the context of the new sandbox to create a bridge, e.g.::
+
+	sim_add hv0           # Create sandbox hv0.
+	as hv0                # Set hv0 as default sandbox.
+	ovs-vsctl add-br br0  # Add bridge br0 inside hv0.
+
+    The Open vSwitch instances that ``sim_add`` creates enable
+    ``dummy`` devices.  This means that bridges and interfaces can be
+    created with type ``dummy`` to indicate that they should be
+    totally simulated, without any reference to system entities.  In
+    fact, ``ovs-sim`` also configures Open vSwitch so that the default
+    system type of bridges and interfaces are replaced by dummy
+    devices.  Other types of devices, however, retain their usual
+    functions, which means that, e.g., vxlan tunnels still act as
+    tunnels (refer to the documentation).
+
+``as`` *sandbox*
+    Sets sandbox as the default simulation target for Open vSwitch
+    commands (e.g. ``ovs-vsctl``, ``ovs-ofctl``, ``ovs-appctl``).
+
+    This command updates the beginning of the shell prompt to indicate
+    the new default target.
+
+``as`` *sandbox* *command* *arg*...
+    Runs the given command with *sandbox* as the simulation target,
+    e.g.  ``as hv0 ovs-vsctl add-br br0`` runs ``ovs-vsctl add-br
+    br0`` within sandbox ``hv0``.  The default target is unchanged.
+
+Interconnection Network Commands
+--------------------------------
+
+When multiple sandboxed Open vSwitch instances exist, one will
+inevitably want to connect them together.  These commands allow for
+that.  Conceptually, an interconnection network is a switch that
+``ovs-sim`` makes it easy to plug into other switches in other
+sandboxed Open vSwitch instances.  Interconnection networks are
+implemented as bridges in the ``main`` switch that ``ovs-sim`` creates
+by default, so to use interconnection networks please avoid working
+with ``main`` directly.
+
+``net_add`` *network*
+    Creates a new interconnection network named *network*.
+
+``net_attach`` *network* *bridge*
+    Adds a new port to *bridge* in the default sandbox (as set with
+    ``as``) and plugs it into interconnection network *network*, which
+    must already have been created by a previous invocation of
+    ``net_add``. The default sandbox must not be ``main``.
+
+OVN Commands
+------------
+
+These commands interact with OVN, the Open Virtual Network.
+
+``ovn_start``
+    Creates and initializes the central OVN databases (both
+    ``ovn-sb(5)`` and ``ovn-nb(5)``) and starts an instance of
+    ``ovsdb-server`` for each one.  Also starts an instance of
+    ``ovn-northd``.
+
+``ovn_attach`` *network* *bridge* *ip* [*masklen*]
+    First, this command attaches bridge to interconnection network
+    network, just like ``net_attach`` *network* *bridge*.  Second, it
+    configures (simulated) IP address *ip* (with network mask length
+    *masklen*, which defaults to 24) on *bridge*. Finally, it
+    configures the Open vSwitch database to work with OVN and starts
+    ``ovn-controller``.
+
+Examples
+========
+
+The following creates a pair of Open vSwitch instances ``hv0`` and
+``hv1``, adds a port named ``vif0`` or ``vif1``, respectively, to each
+one, and then connects the two through an interconnection network
+``n1``::
+
+    net_add n1
+    for i in 0 1; do
+	sim_add hv$i
+	as hv$i ovs-vsctl add-br br0 -- add-port br0 vif$i
+	as hv$i net_attach n1 br0
+    done
+
+Here’s an extended version that also starts OVN::
+
+    ovn_start
+    ovn-nbctl ls-add lsw0
+    net_add n1
+    for i in 0 1; do
+	sim_add hv$i
+	as hv$i
+	ovs-vsctl add-br br-phys
+	ovn_attach n1 br-phys 192.168.0.`expr $i + 1`
+	ovs-vsctl add-port br-int vif$i -- set Interface vif$i external-ids:iface-id=lp$i
+	ovn-nbctl lsp-add lsw0 lp$i
+	ovn-nbctl lsp-set-addresses lp$i f0:00:00:00:00:0$i
+    done
+
+Here’s a primitive OVN "scale test" (adjust the scale by changing
+``n`` in the first line::
+
+    n=200; export n
+    ovn_start
+    net_add n1
+    ovn-nbctl ls-add br0
+    for i in `seq $n`; do
+	(sim_add hv$i
+	as hv$i
+	ovs-vsctl add-br br-phys
+	y=$(expr $i / 256)
+	x=$(expr $i % 256)
+	ovn_attach n1 br-phys 192.168.$y.$x
+	ovs-vsctl add-port br-int vif$i -- set Interface vif$i external-ids:iface-id=lp$i) &
+	case $i in
+	    *50|*00) echo $i; wait ;;
+	esac
+    done
+    wait
+    for i in `seq $n`; do
+	yy=$(printf %02x $(expr $i / 256))
+	xx=$(printf $02x $(expr $i % 256))
+	ovn-nbctl lsp-add br0 lp$i
+	ovn-nbctl lsp-set-addresses lp$i f0:00:00:00:$yy:$xx
+    done
+
+When the scale test has finished initializing, you can watch the
+logical ports come up with a command like this::
+
+    watch 'for i in `seq $n`; do if test `ovn-nbctl lsp-get-up lp$i` != up; then echo $i; fi; done'