Open vSwitch

What is Open vSwitch ?  Open vSwitch is an open source OpenFlow capable virtual switch that is typically used with hypervisor to interconnect virtual machines within a host and virtual machines between different host across the network.  Open vSwitch licenced under Apache 2.0  it is also used on some dedicated switching hardware.  OVS can be a critical in an SDN solutions.

OVS Features  Visibility into inter-VM communication via NetFlow, sFlow(R), IPFIX, SPAN, RSPAN, and GRE-tunneled mirrors  LACP (IEEE 802.1AX-2008)  Standard 802.1Q VLAN model with trunking  BFD and 802.1ag link monitoring  STP (IEEE 802.1D-1998)  Fine-grained QoS control  Support for HFSC qdisc  Per VM interface traffic policing  NIC bonding with source-MAC load balancing, active backup, and L4 hashing  OpenFlow protocol support (including many extensions for virtualization)  IPv6 support  Multiple tunneling protocols (GRE, VXLAN, IPsec, GRE and VXLAN over IPsec)  Remote configuration protocol with C and Python bindings  Kernel and user-space forwarding engine options  Multi-table forwarding pipeline with flow-caching engine  Forwarding layer abstraction to ease porting to new software and hardware platforms The newest version is 2.3.0

Main Component

ovsdb - server  Database that holds switch-level configuration. Bridge, Interface, tunnel definision.  Configuration is stored on disk and survives a reboot.  Log based (good for debugging)  ovsdb-tool command-line tool to manage the database  ovsdb persist the data across reboots. Configures ovs-vswitchd

ovs-vswitchd  Core component in the system: Communicates with outside world using OpenFlow Communicates with ovsdb server using management protocol (ovsdb) Communicates with kernel module over netlink  Support multiple independent datapaths (bridges)  Implements mirroring, bonding, and VLANs through modifications of the same flow table exposed through OF.

openvswitch_mod.ko  Kernel module Handles switching and tunneling Designed to be fast and simple. If flow found, actions are executed otherwise passed to the user space. Implements tunnels and caches flows.

Some OVS utility  ovs-ofctl – management utility for openflow  ovs-dpctl – Open vSwitch datapath management utility  ovs-vsctl – manage the switch through interaction with ovsdb- server  ovs-appctl – utility for managing logging levels  ovsdb-client – monitoring OVS database.

Installing Open vSwitch on Ubuntu  Prepare the system Check the system kernel version and release $ uname –r Stop the network-manager service $ sudo service network-manager stop Update the system. $ sudo apt-get update

Installing Open vSwitch on Ubuntu  Installing dependencies. python-simplejson python-qt4 python-twisted-conch automake autoconf gcc uml-utilities libtool build-essential pkg-config lib-ssl-dev iproute tcpdump Linux-headers Command: $ apt-get install [packet-name]

Installing Open vSwitch on Ubuntu

 Download the Open vSwitch  2 ways:  Download the tar.gz file from the website via web browser  Using command line. $ wget  Extract the tar.gz file. $ tar xf openvswitch tar.gz  Navigate to the folder. $ cd [folder-name]

Installing Open vSwitch on Ubuntu

 Compile and install $./boot.sh $./configure --with-linux=/lib/modules/’uname –r’/build $ sudo make $ sudo make install

Installing Open vSwitch on Ubuntu  After the installation, we need to load the kernel module $ insmod datapath/linux/openvswitch.ko  Create the configuration file. $ touch /usr/local/etc/ovs-vswitch.conf $ mkdir –p /usr/local/etc/openvswitch $ vsdb-tool create /usr/local/etc/openvswitch/conf.db

Installing Open vSwitch on Ubuntu

 Start the ovs-switchd. Before starting ovs-vswitchd itself, we need to start its configuration database, ovsdb-server. Each machine on which Open vSwitch is installed should run its own copy of ovsdb-server. Command: $ ovsdb-server --remote=punix:/usr/local/var/run/openvswitch/db.sock --remote=db:Open_vSwitch,Open_vSwitch,manager_options --private-key=db:Open_vSwitch,SSL,private_key --certificate=db:Open_vSwitch,SSL,certificate --bootstrap-ca-cert=db:Open_vSwitch,SSL,ca_cert --pidfile --detach

Installing Open vSwitch on Ubuntu

 Initialize the database. initialize the database using ovs-vsctl. This is only necessary the first time after you create the database with ovsdb-tool (but running it at any time is harmless): Command: $ ovs-vsctl --no-wait init

Installing Open vSwitch on Ubuntu  Start the Open vSwitch Daemon. Then start the main Open vSwitch daemon, telling it to connect to the same domain socket: Command: $ ovs-vswitchd --pidfile --detach

Installing Open vSwitch on Ubuntu  Start the Open vSwitch Daemon. Then start the main Open vSwitch daemon, telling it to connect to the same domain socket: Command: $ ovs-vswitchd --pidfile --detach

Installing Open vSwitch on Ubuntu  Check the installation and overview the database. Command: $ ovs-vsctl --version $ ovs-vsctl show

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