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19cbf2b8a4
Currently, when we upgrade openvswitch packages, we do a restart of userspace daemons automatically. This does not replace the kernel module. But almost everytime, we want to use the new kernel module that comes with the new version. This means that we need to manually do a "force-reload-kmod". This step, reloads the kernel module and also restarts the userspace daemons. This gives us a total of two restarts of userspace daemons. This is quite expensive in a hypervisor with hundreds of VMs sending real traffic. This also hurts the controller as it gets two reconnections in a short amount of time. With this patch, during a package upgrade, if the kernel module on disk is different than the one that is loaded, we will automatically do a force-reload-kmod while openvswitch-switch is installed. If not, we will just do a "restart" like before. One can install the kernel package first and then install the userspace packages in 2 separate steps to enforce a single 'force-reload-kmod'. If anyone wants to just restart the userspace package instead of force-reload-kmod, they can set the value of OVS_FORCE_RELOAD_KMOD=no while installing the package. Ex: OVS_FORCE_RELOAD_KMOD=no dpkg -i openvswitch-switch* Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>
Open vSwitch <http://openvswitch.org>
What is Open vSwitch?
---------------------
Open vSwitch is a multilayer software switch licensed under the open
source Apache 2 license. Our goal is to implement a production
quality switch platform that supports standard management interfaces
and opens the forwarding functions to programmatic extension and
control.
Open vSwitch is well suited to function as a virtual switch in VM
environments. In addition to exposing standard control and visibility
interfaces to the virtual networking layer, it was designed to support
distribution across multiple physical servers. Open vSwitch supports
multiple Linux-based virtualization technologies including
Xen/XenServer, KVM, and VirtualBox.
The bulk of the code is written in platform-independent C and is
easily ported to other environments. The current release of Open
vSwitch supports the following features:
* Standard 802.1Q VLAN model with trunk and access ports
* NIC bonding with or without LACP on upstream switch
* NetFlow, sFlow(R), and mirroring for increased visibility
* QoS (Quality of Service) configuration, plus policing
* GRE, GRE over IPSEC, VXLAN, and LISP tunneling
* 802.1ag connectivity fault management
* OpenFlow 1.0 plus numerous extensions
* Transactional configuration database with C and Python bindings
* High-performance forwarding using a Linux kernel module
The included Linux kernel module supports Linux 2.6.18 and up, with
testing focused on 2.6.32 with Centos and Xen patches. Open vSwitch
also has special support for Citrix XenServer and Red Hat Enterprise
Linux hosts.
Open vSwitch can also operate, at a cost in performance, entirely in
userspace, without assistance from a kernel module. This userspace
implementation should be easier to port than the kernel-based switch.
It is considered experimental.
What's here?
------------
The main components of this distribution are:
* ovs-vswitchd, a daemon that implements the switch, along with
a companion Linux kernel module for flow-based switching.
* ovsdb-server, a lightweight database server that ovs-vswitchd
queries to obtain its configuration.
* ovs-dpctl, a tool for configuring the switch kernel module.
* Scripts and specs for building RPMs for Citrix XenServer and Red
Hat Enterprise Linux. The XenServer RPMs allow Open vSwitch to
be installed on a Citrix XenServer host as a drop-in replacement
for its switch, with additional functionality.
* ovs-vsctl, a utility for querying and updating the configuration
of ovs-vswitchd.
* ovs-appctl, a utility that sends commands to running Open
vSwitch daemons.
* ovsdbmonitor, a GUI tool for remotely viewing OVS databases and
OpenFlow flow tables.
Open vSwitch also provides some tools:
* ovs-controller, a simple OpenFlow controller.
* ovs-ofctl, a utility for querying and controlling OpenFlow
switches and controllers.
* ovs-pki, a utility for creating and managing the public-key
infrastructure for OpenFlow switches.
* A patch to tcpdump that enables it to parse OpenFlow messages.
What other documentation is available?
--------------------------------------
To install Open vSwitch on a regular Linux or FreeBSD host, please
read INSTALL. For specifics around installation on a specific
platform, please see one of these files:
- INSTALL.Debian
- INSTALL.Fedora
- INSTALL.RHEL
- INSTALL.XenServer
To use Open vSwitch...
- ...with KVM on Linux, read INSTALL, read INSTALL.KVM.
- ...with Libvirt, read INSTALL.Libvirt.
- ...without using a kernel module, read INSTALL.userspace.
For answers to common questions, read FAQ.
To learn how to set up SSL support for Open vSwitch, read INSTALL.SSL.
To learn about some advanced features of the Open vSwitch software
switch, read the tutorial in tutorial/Tutorial.
Each Open vSwitch userspace program is accompanied by a manpage. Many
of the manpages are customized to your configuration as part of the
build process, so we recommend building Open vSwitch before reading
the manpages.
Contact
-------
bugs@openvswitch.org
http://openvswitch.org/