- How to Install Open vSwitch on Linux and FreeBSD
- ================================================
+ How to Install Open vSwitch on Linux, FreeBSD and NetBSD
+ ========================================================
This document describes how to build and install Open vSwitch on a
-generic Linux or FreeBSD host. For specifics around installation on a
-specific platform, please see one of these files:
+generic Linux, FreeBSD, or NetBSD host. For specifics around installation
+on a specific platform, please see one of these files:
- INSTALL.Debian
- INSTALL.Fedora
(On Debian "lenny" the above can be installed with "apt-get install
python-json python-qt4 python-zopeinterface python-twisted-conch".)
-Building and Installing Open vSwitch for Linux or FreeBSD
-=========================================================
+Building and Installing Open vSwitch for Linux, FreeBSD or NetBSD
+=================================================================
Once you have installed all the prerequisites listed above in the Base
Prerequisites section, follow the procedure below to build.
- If there is no important data in your database, then you may
delete the database file and recreate it with ovsdb-tool,
following the instructions under "Building and Installing Open
- vSwitch for Linux or FreeBSD".
+ vSwitch for Linux, FreeBSD or NetBSD".
- If you want to preserve the contents of your database, back it
up first, then use "ovsdb-tool convert" to upgrade it, e.g.:
% ovsdb-tool convert /usr/local/etc/openvswitch/conf.db vswitchd/vswitch.ovsschema
4. Start the Open vSwitch daemons as described under "Building and
- Installing Open vSwitch for Linux or FreeBSD" above.
+ Installing Open vSwitch for Linux, FreeBSD or NetBSD" above.
+
+Hot Upgrading
+=============
+Upgrading Open vSwitch from one version to the next version with minimum
+disruption of traffic going through the system that is using that Open vSwitch
+needs some considerations:
+
+1. If the upgrade only involves upgrading the userspace utilities and daemons
+of Open vSwitch, make sure that the new userspace version is compatible with
+the previously loaded kernel module.
+
+2. An upgrade of userspace daemons means that they have to be restarted.
+Restarting the daemons means that the Openflow flows in the ovs-vswitchd daemon
+will be lost. One way to restore the flows is to let the controller
+re-populate it. Another way is to save the previous flows using a utility
+like ovs-ofctl and then re-add them after the restart. Restoring the old flows
+is accurate only if the new Open vSwitch interfaces retain the old 'ofport'
+values.
+
+3. When the new userspace daemons get restarted, they automatically flush
+the old flows setup in the kernel. This can be expensive if there are hundreds
+of new flows that are entering the kernel but userspace daemons are busy
+setting up new userspace flows from either the controller or an utility like
+ovs-ofctl. Open vSwitch database provides an option to solve this problem
+through the other_config:flow-restore-wait column of the Open_vSwitch table.
+Refer to the ovs-vswitchd.conf.db(5) manpage for details.
+
+4. If the upgrade also involves upgrading the kernel module, the old kernel
+module needs to be unloaded and the new kernel module should be loaded. This
+means that the kernel network devices belonging to Open vSwitch is recreated
+and the kernel flows are lost. The downtime of the traffic can be reduced
+if the userspace daemons are restarted immediately and the userspace flows
+are restored as soon as possible.
+
+The ovs-ctl utility's "restart" function only restarts the userspace daemons,
+makes sure that the 'ofport' values remain consistent across restarts, restores
+userspace flows using the ovs-ofctl utility and also uses the
+other_config:flow-restore-wait column to keep the traffic downtime to the
+minimum. The ovs-ctl utility's "force-reload-kmod" function does all of the
+above, but also replaces the old kernel module with the new one. Open vSwitch
+startup scripts for Debian, XenServer and RHEL use ovs-ctl's functions and it
+is recommended that these functions be used for other software platforms too.
Running the Testsuite
=====================
other areas of Open vSwitch.
You must configure and build Open vSwitch (steps 1 through 3 in
-"Building and Installing Open vSwitch for Linux or FreeBSD" above)
+"Building and Installing Open vSwitch for Linux, FreeBSD or NetBSD" above)
before you run the testsuite. You do not need to install Open vSwitch
or to build or load the kernel module to run the testsuite. You do
not need supervisor privilege to run the testsuite.
git://git.onelab.eu / sliver-openvswitch.git / blobdiff