INSTALL.XenServer

   1            How to Install Open vSwitch on Citrix XenServer
   2            ===============================================
   3
   4 This document describes how to build and install Open vSwitch on a
   5 Citrix XenServer host.  If you want to install Open vSwitch on a
   6 generic Linux or BSD host, see INSTALL instead.
   7
   8 These instructions have been tested with XenServer 5.6 FP1.
   9
  10 Building Open vSwitch for XenServer
  11 -----------------------------------
  12
  13 You may build from an Open vSwitch distribution tarball or from an
  14 Open vSwitch Git tree.  The recommended build environment to build
  15 RPMs for Citrix XenServer is the DDK VM available from Citrix.
  16
  17 1. If you are building from an Open vSwitch Git tree, then you will
  18    need to first create a distribution tarball by running "./boot.sh;
  19    ./configure; make dist" in the Git tree.  You cannot run this in
  20    the DDK VM, because it lacks tools that are necessary to bootstrap
  21    the Open vSwitch distribution.  Instead, you must run this on a
  22    machine that has the tools listed in INSTALL as prerequisites for
  23    building from a Git tree.
  24
  25 2. Copy the distribution tarball into /usr/src/redhat/SOURCES inside
  26    the DDK VM.
  27
  28 3. In the DDK VM, unpack the distribution tarball into a temporary
  29    directory and "cd" into the root of the distribution tarball.
  30
  31 4. To build Open vSwitch userspace, run:
  32
  33        rpmbuild -bb xenserver/openvswitch-xen.spec
  34
  35    This produces three RPMs in /usr/src/redhat/RPMS/i386:
  36    "openvswitch", "openvswitch-modules-xen", and
  37    "openvswitch-debuginfo".
  38
  39 Build Parameters
  40 ----------------
  41
  42 openvswitch-xen.spec needs to know a number of pieces of information
  43 about the XenServer kernel.  Usually, it can figure these out for
  44 itself, but if it does not do it correctly then you can specify them
  45 yourself as parameters to the build.  Thus, the final "rpmbuild" step
  46 above can be elaborated as:
  47
  48    VERSION=<Open vSwitch version>
  49    KERNEL_NAME=<Xen Kernel name>
  50    KERNEL_VERSION=<Xen Kernel version>
  51    KERNEL_FLAVOR=<Xen Kernel flavor(suffix) >
  52    rpmbuild \
  53         -D "openvswitch_version $VERSION" \
  54         -D "kernel_name $KERNEL_NAME" \
  55         -D "kernel_version $KERNEL_VERSION" \
  56         -D "kernel_flavor $KERNEL_FLAVOR" \
  57         -bb xenserver/openvswitch-xen.spec
  58
  59 where:
  60
  61     <openvswitch version> is the version number that appears in the
  62     name of the Open vSwitch tarball, e.g. 0.90.0.
  63
  64     <Xen Kernel name> is the name of the XenServer kernel package,
  65     e.g. kernel-xen or kernel-NAME-xen, without the "kernel-" prefix.
  66
  67     <Xen Kernel version> is the output of:
  68     rpm -q --queryformat "%{Version}-%{Release}" <kernel-devel-package>,
  69     e.g. 2.6.32.12-0.7.1.xs5.6.100.323.170596, where <kernel-devel-package> is
  70     the name of the -devel package corresponding to <Xen Kernel name>.
  71
  72     <Xen Kernel flavor (suffix) > is either "xen" or "kdump".
  73     The "xen" flavor is the main running kernel flavor and the "kdump" flavor is
  74     the crashdump kernel flavor. Commonly, one would specify "xen" here.
  75
  76 Installing Open vSwitch for XenServer
  77 -------------------------------------
  78
  79 To install Open vSwitch on a XenServer host, or to upgrade to a newer version,
  80 copy the "openvswitch" and "openvswitch-modules-xen" RPMs to that host with
  81 "scp", then install them with "rpm -U", e.g.:
  82
  83      scp openvswitch-$VERSION-1.i386.rpm \
  84          openvswitch-modules-xen-$XEN_KERNEL_VERSION-$VERSION-1.i386.rpm \
  85          root@<host>:
  86 (At this point you will have to enter <host>'s root password.)
  87      ssh root@<host>
  88 (At this point you will have to enter <host>'s root password again.)
  89      rpm -U openvswitch-$VERSION-1.i386.rpm \
  90          openvswitch-modules-xen-$XEN_KERNEL_VERSION-$VERSION-1.i386.rpm
  91
  92 To uninstall Open vSwitch from a XenServer host, remove the packages:
  93
  94      ssh root@<host>
  95 (At this point you will have to enter <host>'s root password again.)
  96      rpm -e openvswitch openvswitch-modules-xen-$XEN_KERNEL_VERSION
  97
  98 After installing or uninstalling Open vSwitch, the XenServer should be
  99 rebooted as soon as possible.
 100
 101 Open vSwitch Boot Sequence on XenServer
 102 ---------------------------------------
 103
 104 When Open vSwitch is installed on XenServer, its startup script
 105 /etc/init.d/openvswitch runs early in boot.  It does roughly the
 106 following:
 107
 108         * Loads the OVS kernel module, openvswitch.
 109
 110         * Starts ovsdb-server, the OVS configuration database.
 111
 112         * XenServer expects there to be no bridges configured at
 113           startup, but the OVS configuration database likely still has
 114           bridges configured from before reboot.  To match XenServer
 115           expectations, the startup script deletes all configured
 116           bridges from the database.
 117
 118         * Starts ovs-vswitchd, the OVS switching daemon.
 119
 120 At this point in the boot process, then, there are no Open vSwitch
 121 bridges, even though all of the Open vSwitch daemons are running.
 122 Later on in boot, /etc/init.d/management-interface (part of XenServer,
 123 not Open vSwitch) creates the bridge for the XAPI management interface
 124 by invoking /opt/xensource/libexec/interface-reconfigure.  Normally
 125 this program consults XAPI's database to obtain information about how
 126 to configure the bridge, but XAPI is not running yet[*] so it instead
 127 consults /var/xapi/network.dbcache, which is a cached copy of the most
 128 recent network configuration.
 129
 130 [*] Even if XAPI were running, if this XenServer node is a pool slave
 131     then the query would have to consult the master, which requires
 132     network access, which begs the question of how to configure the
 133     management interface.
 134
 135 XAPI starts later on in the boot process.  XAPI can then create other
 136 bridges on demand using /opt/xensource/libexec/interface-reconfigure.
 137 Now that XAPI is running, that program consults XAPI directly instead
 138 of reading the cache.
 139
 140 As part of its own startup, XAPI invokes the Open vSwitch XAPI plugin
 141 script /etc/xapi.d/openvswitch-cfg-update passing the "update"
 142 command.  The plugin script does roughly the following:
 143
 144         * Calls /opt/xensource/libexec/interface-reconfigure with the
 145           "rewrite" command, to ensure that the network cache is
 146           up-to-date.
 147
 148         * Queries the Open vSwitch manager setting (named
 149           "vswitch_controller") from the XAPI database for the
 150           XenServer pool.
 151
 152         * If XAPI and OVS are configured for different managers, or if
 153           OVS is configured for a manager but XAPI is not, runs
 154           "ovs-vsctl emer-reset" to bring the Open vSwitch
 155           configuration to a known state.  One effect of emer-reset is
 156           to deconfigure any manager from the OVS database.
 157
 158         * If XAPI is configured for a manager, configures the OVS
 159           manager to match with "ovs-vsctl set-manager".
 160
 161 The Open vSwitch boot sequence only configures an OVS configuration
 162 database manager.  There is no way to directly configure an OpenFlow
 163 controller on XenServer and, as a consequence of the step above that
 164 deletes all of the bridges at boot time, controller configuration only
 165 persists until XenServer reboot.  The configuration database manager
 166 can, however, configure controllers for bridges.  See the BUGS section
 167 of ovs-controller(8) for more information on this topic.
 168
 169 Reporting Bugs
 170 --------------
 171
 172 Please report problems to bugs@openvswitch.org.