ovs的卸载
使用apt-get安装的openvswitch，然后卸载好麻烦撒，而且还没有相关资料说一下怎么删除的，特此记录一下，希望有个参考
首先把服务器上使用ovs新建的虚拟网桥全部删除掉
然后把原有的内核删除 sudo rmmod openvswitch
再然后把之前服务停掉
sudo killall ovsdb-server
sudo killall ovs-vswitchd
最后按照说明文档即可（很多命令需要sudo的，请注意，一下标红的是用到的命令）
once you have installed all the prerequisites listed above in the Base
Prerequisites section, follow the procedure below to build.
1. If you pulled the sources directly from an Open vSwitch Git tree,
run boot.sh in the top source directory:
% ./boot.sh
2. In the top source directory, configure the package by running the
configure script. You can usually invoke configure without any
arguments:
% ./configure
By default all files are installed under /usr/local. If you want
to install into, e.g., /usr and /var instead of /usr/local and
/usr/local/var, add options as shown here:
% ./configure --prefix=/usr --localstatedir=/var
To use a specific C compiler for compiling Open vSwitch user
programs, also specify it on the configure command line, like so:
% ./configure CC=gcc-4.2
To build the Linux kernel module, so that you can run the
kernel-based switch, pass the location of the kernel build
directory on --with-linux. For example, to build for a running
instance of Linux:
% ./configure --with-linux=/lib/modules/`uname -r`/build
If you wish to build the kernel module for an architecture other
than the architecture of the machine used for the build, you may
specify the kernel architecture string using the KARCH variable
when invoking the configure script. For example, to build for MIPS
with Linux:
% ./configure --with-linux=/path/to/linux KARCH=mips
The configure script accepts a number of other options and honors
additional environment variables. For a full list, invoke
configure with the --help option.
3. Run make in the top source directory:
% make
4. Become root by running "su" or another program.
5. Run "make install" to install the executables and manpages into the
running system, by default under /usr/local.
6. If you built kernel modules, you may load them with "insmod", e.g.:
% insmod datapath/linux/openvswitch_mod.ko
You may need to specify a full path to insmod, e.g. /sbin/insmod.
To verify that the modules have been loaded, run "/sbin/lsmod" and
check that openvswitch_mod is listed.
If the "insmod" operation fails, look at the last few kernel log
messages (e.g. with "dmesg | tail"):
- The message "openvswitch_mod: exports duplicate symbol
br_should_route_hook (owned by bridge)" means that the bridge
module is loaded. Run "/sbin/rmmod bridge" to remove it.
If "/sbin/rmmod bridge" fails with "ERROR: Module bridge does
not exist in /proc/modules", then the bridge is compiled into
the kernel, rather than as a module. Open vSwitch does not
support this configuration (see "Build Requirements", above).
- The message "openvswitch_mod: exports duplicate symbol
dp_ioctl_hook (owned by ofdatapath)" means that the ofdatapath
module from the OpenFlow reference implementation is loaded.
Run "/sbin/rmmod ofdatapath" to remove it. (You might have to
delete any existing datapaths beforehand, using the "dpctl"
program included with the OpenFlow reference implementation.
"ovs-dpctl" will not work.)
- Otherwise, the most likely problem is that Open vSwitch was
built for a kernel different from the one into which you are
trying to load it. Run "modinfo" on openvswitch_mod.ko and on
a module built for the running kernel, e.g.:
% /sbin/modinfo openvswitch_mod.ko
% /sbin/modinfo /lib/modules/`uname -r`/kernel/net/bridge/bridge.ko
Compare the "vermagic" lines output by the two commands. If
they differ, then Open vSwitch was built for the wrong kernel.
- If you decide to report a bug or ask a question related to
module loading, please include the output from the "dmesg" and
"modinfo" commands mentioned above.
There is an optional module parameter to openvswitch_mod.ko called
vlan_tso that enables TCP segmentation offload over VLANs on NICs
that support it. Many drivers do not expose support for TSO on VLANs
in a way that Open vSwitch can use but there is no way to detect
whether this is the case. If you know that your particular driver can
handle it (for example by testing sending large TCP packets over VLANs)
then passing in a value of 1 may improve performance. Modules built for
Linux kernels 2.6.37 and later, as well as specially patched versions
of earlier kernels, do not need this and do not have this parameter. If
you do not understand what this means or do not know if your driver
will work, do not set this.
7. Initialize the configuration database using ovsdb-tool, e.g.:
% mkdir -p /usr/local/etc/openvswitch
% ovsdb-tool create /usr/local/etc/openvswitch/conf.db vswitchd/vswitch.ovsschema（可能文件目录已经有，将create变为convert）
Startup
=======
Before starting ovs-vswitchd itself, you need to start its
configuration database, ovsdb-server. Each machine on which Open
vSwitch is installed should run its own copy of ovsdb-server.
Configure it to use the database you created during step 7 of
installation, above, to listen on a Unix domain socket, to connect to
any managers specified in the database itself, and to use the SSL
configuration in the database:
% ovsdb-server --remote=punix:/usr/local/var/run/openvswitch/db.sock \
--remote=db:Open_vSwitch,manager_options \
--private-key=db:SSL,private_key \
--certificate=db:SSL,certificate \
--bootstrap-ca-cert=db:SSL,ca_cert \
--pidfile --detach
(If you built Open vSwitch without SSL support, then omit
--private-key, --certificate, and --bootstrap-ca-cert.)
Then initialize the database using ovs-vsctl. This is only
necessary the first time after you create the database with
ovsdb-tool (but running it at any time is harmless):
% ovs-vsctl --no-wait init
Then start the main Open vSwitch daemon, telling it to connect to the
same Unix domain socket:
% ovs-vswitchd --pidfile --detach