2013年5月27日 星期一
OpenvSwitch Component Introduction
| ovs−appctl − utility for configuring running Open vSwitch daemons ovs−controller − simple OpenFlow controller reference implementation
|
| ovs−pki − OpenFlow public key infrastructure management utility |
| ovs−ofctl − administer OpenFlow switches ovs−vswitchd − Open vSwitch daemon |
2013年5月10日 星期五
openvswitch boot sequence on Xenserver
Open vSwitch Boot Sequence on XenServer
---------------------------------------
When Open vSwitch is installed on XenServer, its startup script
/etc/init.d/openvswitch runs early in boot. It does roughly the
following:
* Loads the OVS kernel module, openvswitch.
* Starts ovsdb-server, the OVS configuration database.
* XenServer expects there to be no bridges configured at
startup, but the OVS configuration database likely still has
bridges configured from before reboot. To match XenServer
expectations, the startup script deletes all configured
bridges from the database.
* Starts ovs-vswitchd, the OVS switching daemon.
At this point in the boot process, then, there are no Open vSwitch
bridges, even though all of the Open vSwitch daemons are running.
Later on in boot, /etc/init.d/management-interface (part of XenServer,
not Open vSwitch) creates the bridge for the XAPI management interface
by invoking /opt/xensource/libexec/interface-reconfigure. Normally
this program consults XAPI's database to obtain information about how
to configure the bridge, but XAPI is not running yet[*] so it instead
consults /var/xapi/network.dbcache, which is a cached copy of the most
recent network configuration.
[*] Even if XAPI were running, if this XenServer node is a pool slave
then the query would have to consult the master, which requires
network access, which begs the question of how to configure the
management interface.
XAPI starts later on in the boot process. XAPI can then create other
bridges on demand using /opt/xensource/libexec/interface-reconfigure.
Now that XAPI is running, that program consults XAPI directly instead
of reading the cache.
As part of its own startup, XAPI invokes the Open vSwitch XAPI plugin
script /etc/xapi.d/openvswitch-cfg-update passing the "update"
command. The plugin script does roughly the following:
* Calls /opt/xensource/libexec/interface-reconfigure with the
"rewrite" command, to ensure that the network cache is
up-to-date.
* Queries the Open vSwitch manager setting (named
"vswitch_controller") from the XAPI database for the
XenServer pool.
* If XAPI and OVS are configured for different managers, or if
OVS is configured for a manager but XAPI is not, runs
"ovs-vsctl emer-reset" to bring the Open vSwitch
configuration to a known state. One effect of emer-reset is
to deconfigure any manager from the OVS database.
* If XAPI is configured for a manager, configures the OVS
manager to match with "ovs-vsctl set-manager".
Notes
-----
* The Open vSwitch boot sequence only configures an OVS configuration
database manager. There is no way to directly configure an OpenFlow
controller on XenServer and, as a consequence of the step above that
deletes all of the bridges at boot time, controller configuration only
persists until XenServer reboot. The configuration database manager
can, however, configure controllers for bridges. See the BUGS section
of ovs-controller(8) for more information on this topic.
* The Open vSwitch startup script automatically adds a firewall rule
to allow GRE traffic. This rule is needed for the XenServer feature
called "Cross-Host Internal Networks" (CHIN) that uses GRE. If a user
configures tunnels other than GRE (ex: VXLAN, LISP), they will have
to either manually add a iptables firewall rule to allow the tunnel traffic
or add it through a startup script (Please refer to the "enable-protocol"
command in the ovs-ctl(8) manpage).
http://openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=blob_plain;f=INSTALL.XenServer;hb=HEAD
2013年5月8日 星期三
Xenserver交換Networking Backend
Switching between Linux Bridge and Open VSwitch
Note: Open vSwitch has been the default network backend since XenServer 6.0.0 and XCP 1.5. If you switched to using Linux Bridge and this proved beneficial to you, please let us know.
To see what network backend you are currently using, run in dom0:
cat /etc/xensource/network.conf
To switch to using the Linux Bridge network backend, run in dom0:
xe-switch-network-backend bridge
To switch to using Open vSwitch network backend, run in dom0:
xe-switch-network-backend openvswitch
2013年5月7日 星期二
OpenvSwitch
* 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 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.
安裝注意事項
Open vSwitch可以用kernel modules來support以降低cost，或者可以安裝到userspace但是會增加performance的cost。2013年4月19日 星期五
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