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5cb12f2eef
Commitd66880ee(xenserver: Clean up /usr/sbin/brctl dangling symlink.) attempted to revert the original XenServer-shipped versions of scripts replaced by OVS during an RPM upgrade, but the logic was incorrect. It assumed that %postun of the package being replaced was run before the %post of the new version replacing it. The reverse is actually true. Make upgrade and erase cases both work correctly by simply checking whether any of the files ever replaced in any OVS version are dangling symlinks, and if so, attempt to copy the saved XenServer original back to its rightful place. In the upgrade case, if the newly-installed version of OVS lacks any of the scripts in the previous version, those will be reverted. In the erase case, none of the OVS replacements will exist, so they will all be dangling symlinks and will all be reverted. Furthermore, replace any dangling symlink from /usr/sbin/xen-bugtool to the now-nonexistent OVS replacement (caused by commit92dbd5c9(xenserver: Replace customized xen-bugtool with plugin to collect qdisc info.)). Lastly, prevent accidental reversion of files replaced by OVS during rpm -U (also caused by commit92dbd5c9). Bug #4696.
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
(e.g. NetFlow, sFlow(R), RSPAN, ERSPAN, IOS-like CLI), 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:
* Visibility into inter-VM communication via NetFlow, sFlow, SPAN,
and RSPAN
* Standard 802.1Q VLAN model with trunking
* Per VM policing
* NIC bonding with source-MAC load balancing
* Kernel-based forwarding
* Support for OpenFlow
* Compatibility layer for the Linux bridging code
The included Linux kernel module supports Linux 2.6.18 and up, with
testing focused on 2.6.18 with Centos and Xen patches and version
2.6.26 from kernel.org. Open vSwitch also has special support for
Citrix XenServer 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-brcompatd, a daemon that allows ovs-vswitchd to act as a
drop-in replacement for the Linux bridge in many environments,
along with a companion Linux kernel module to intercept bridge
ioctls.
* ovs-dpctl, a tool for configuring the switch kernel module.
* Scripts and specs for building RPMs that 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 an OpenFlow implementation and tools for
those interested in OpenFlow but not additional Open vSwitch features:
* ovs-openflowd, an alternative to ovs-vswitchd that implements a
simple OpenFlow switch, without the special features provided by
ovs-vswitchd.
* 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 machine, read INSTALL.Linux.
To use Open vSwitch as a drop-in replacement for the Linux bridge,
read INSTALL.bridge.
To build RPMs for installing Open vSwitch on a Citrix XenServer host
or resource pool, read INSTALL.XenServer.
To use Open vSwitch with KVM on Linux, read INSTALL.Linux, then
INSTALL.KVM.
To install Open vSwitch without using a kernel module, read
INSTALL.userspace.
To learn how to set up SSL support for Open vSwitch, read INSTALL.SSL.
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/