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How to Use Open vSwitch with KVM
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=================================
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This document describes how to use Open vSwitch with the Kernel-based
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Virtual Machine (KVM). This document assumes that you have read and
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followed [INSTALL.md] to get Open vSwitch setup on your Linux system.
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First, follow the setup instructions in [INSTALL.md] to get a working
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Open vSwitch installation.
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KVM uses tunctl to handle various bridging modes, which you can
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install with the Debian/Ubuntu package uml-utilities.
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% apt-get install uml-utilities
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Next, you will need to modify or create custom versions of the qemu-ifup
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and qemu-ifdown scripts. In this guide, we'll create custom versions
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that make use of example Open vSwitch bridges that we'll describe in this
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Create the following two files and store them in known locations.
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For example /etc/ovs-ifup and /etc/ovs-ifdown
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/sbin/ifconfig $1 0.0.0.0 up
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ovs-vsctl add-port ${switch} $1
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/sbin/ifconfig $1 0.0.0.0 down
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ovs-vsctl del-port ${switch} $1
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At the end of [INSTALL.md], it describes basic usage of creating
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bridges and ports. If you haven't already, create a bridge named
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br0 with the following command:
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% ovs-vsctl add-br br0
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Then, add a port to the bridge for the NIC that you want your guests
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to communicate over (e.g. eth0):
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% ovs-vsctl add-port br0 eth0
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Please refer to ovs-vsctl(8) for more details.
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Next, we'll start a guest that will use our ifup and ifdown scripts.
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% kvm -m 512 -net nic,macaddr=00:11:22:EE:EE:EE -net \
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tap,script=/etc/ovs-ifup,downscript=/etc/ovs-ifdown -drive \
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file=/path/to/disk-image,boot=on
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This will start the guest and associate a tap device with it. The
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ovs-ifup script will add a port on the br0 bridge so that the
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guest will be able to communicate over that bridge.
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To get some more information and for debugging you can use Open
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vSwitch utilities such as ovs-dpctl and ovs-ofctl, For example:
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You should see tap devices for each KVM guest added as ports to
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the bridge (e.g. tap0)
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Please refer to ovs-dpctl(8) and ovs-ofctl(8) for more details.
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Please report problems to bugs@openvswitch.org.
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[INSTALL.md]:INSTALL.md