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:
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.Installs all of the Open vSwitch manpages into a
man
subdirectory of sandbox and adjusts theMANPATH
environment variable so thatman
and other manpage viewers can find them.Creates a simulated Open vSwitch named
main
and sets it up as the default target for OVS commands, as if the followingovs-sim
commands had been run:sim_add main as main
See Commands, below, for an explanation.
- 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.
- 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¶
- 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
sandboxStarts 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 enabledummy
devices. This means that bridges and interfaces can be created with typedummy
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
sandboxSets 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
runsovs-vsctl add-br br0
within sandboxhv0
. 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 ofnet_add
. The default sandbox must not bemain
.
OVN Commands¶
These commands interact with OVN, the Open Virtual Network.
ovn_start
[options]Creates and initializes the central OVN databases (both
ovn-sb(5)
andovn-nb(5)
) and starts an instance ofovsdb-server
for each one. Also starts an instance ofovn-northd
.The following options are available:
--nbdb-model
model- Uses the given database model for the northbound database.
The model may be
standalone
(the default),backup
, orclustered
. --nbdb-servers
n- For a clustered northbound database, the number of servers in the cluster. The default is 3.
--sbdb-model
model- Uses the given database model for the southbound database.
The model may be
standalone
(the default),backup
, orclustered
. --sbdb-servers
n- For a clustered southbound database, the number of servers in the cluster. The default is 3.
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 startsovn-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 --sbdb-model=clustered
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'