What is Open vSwitch?
Open vSwitch is a production quality, multilayer virtual switch licensed under the open source Apache 2.0 license. It is designed to enable massive network automation through programmatic extension, while still supporting standard management interfaces and protocols (e.g. NetFlow, sFlow, IPFIX, RSPAN, CLI, LACP, 802.1ag). In addition, it is designed to support distribution across multiple physical servers similar to VMware's vNetwork distributed vswitch or Cisco's Nexus 1000V. See full feature list here
Why Open vSwitch ?
https://github.com/openvswitch/ovs/blob/master/Documentation/intro/why-ovs.rst
OVN:
http://www.openvswitch.org/support/dist-docs/ovn-architecture.7.html
CMS | | +-----------|-----------+ | | | | OVN/CMS Plugin | | | | | | | | OVN Northbound DB | | | | | | | | ovn-northd | | | | +-----------|-----------+ | | +-------------------+ | OVN Southbound DB | +-------------------+ | | +------------------+------------------+ | | | HV 1 | | HV n | +---------------|---------------+ . +---------------|---------------+ | | | . | | | | ovn-controller | . | ovn-controller | | | | | . | | | | | | | | | | | | | ovs-vswitchd ovsdb-server | | ovs-vswitchd ovsdb-server | | | | | +-------------------------------+ +-------------------------------+
在继续之前，做好先理解一下 namespace:
[cloud][sdn] network namespace
下面两篇中文介绍，内容相似，写的都不咋样。
http://fishcried.com/2016-02-09/openvswitch-ops-guide/
https://blog.kghost.info/2014/11/19/openvswitch-internal/
这个偏实践指导，写的好：
https://www.ibm.com/developerworks/cn/cloud/library/1401_zhaoyi_openswitch/
从源码编译：
文档：https://docs.openvswitch.org/en/latest/intro/install/general/
需要注意是否支持内核模块的编译，有所不同。
[root@D128 thirdparty]# git clone https://github.com/openvswitch/ovs.git [root@D128 ovs]# git checkout v2.7.0 [root@D128 ovs]# yum install autoconf automake libtool [root@D128 ovs]# ./boot.sh [root@D128 ovs]# ./configure --prefix=/root/BUILD_ovs/ [root@D128 ovs]# make [root@D128 ovs]# make install
上边是没编译内核模块的。。。
再编个内核模块吧！！
[root@D128 ovs]# yum install kernel-devel-$(uname -r) [root@D128 ovs]# ./configure --prefix=/root/BUILD_ovs/ --with-linux=/lib/modules/$(uname -r)/build [root@D128 ovs]# uname -a Linux D128 3.10.0-693.el7.x86_64 #1 SMP Tue Aug 22 21:09:27 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
kernel版本太旧，编不过。降版本到v2.6.0
[root@D128 ovs]# git checkout v2.6.0 Previous HEAD position was c298ef7... Set release date for 2.7.0. HEAD is now at 7a0f907... Set release date for 2.6.0. [root@D128 ovs]# git branch * (detached from v2.6.0) master [root@D128 ovs]#
还是编不过。如果想编译通过必须要找对彼此兼容的版本。算了直接用centos自带的ko（反正是学习了解阶段，但愿能兼容跑起来）。。。
[root@D128 ovs]# modprobe openvswitch [root@D128 ovs]# lsmod|grep openvswitch openvswitch 106996 0 nf_nat_ipv6 14131 1 openvswitch nf_nat_ipv4 14115 1 openvswitch nf_defrag_ipv6 35104 2 openvswitch,nf_conntrack_ipv6 nf_nat 26787 3 openvswitch,nf_nat_ipv4,nf_nat_ipv6 nf_conntrack 133387 6 openvswitch,nf_nat,nf_nat_ipv4,nf_nat_ipv6,nf_conntrack_ipv4,nf_conntrack_ipv6 libcrc32c 12644 4 xfs,openvswitch,nf_nat,nf_conntrack [root@D128 ovs]#
运行：
[root@D128 ovs]# export PATH=$PATH:/root/BUILD_ovs/share/openvswitch/scripts/ [root@D128 ~]# ovs-ctl --system-id=random start Starting ovsdb-server [ OK ] Configuring Open vSwitch system IDs [ OK ] Starting ovs-vswitchd [ OK ] Enabling remote OVSDB managers [ OK ] [root@D128 ~]#
数据库应该已经建立了默认的，并且都初始化了。
测试：
[root@D128 BUILD_ovs]# ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:2f:cf:32 brd ff:ff:ff:ff:ff:ff [root@D128 BUILD_ovs]# ./bin/ovs-vsctl add-br br0 [root@D128 BUILD_ovs]# ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:2f:cf:32 brd ff:ff:ff:ff:ff:ff 3: ovs-system: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000 link/ether 92:e5:c6:d2:ec:a2 brd ff:ff:ff:ff:ff:ff 4: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000 link/ether be:e8:bd:df:ff:41 brd ff:ff:ff:ff:ff:ff [root@D128 BUILD_ovs]# ./bin/ovs-vsctl add-port br0 ens33 [root@D128 BUILD_ovs]# brctl show bridge name bridge id STP enabled interfaces [root@D128 BUILD_ovs]#
ovs-vsctl add-br 增加的这俩个设备是什么？
我写了个脚本去判断：
[root@D128 ~]# cat ip_link_show_type.sh #! /bin/bash TYPE=" vlan veth vcan dummy ifb macvlan macvtap bridge bond ipoib ip6tnl ipip sit vxlan gre gretap ip6gre ip6gretap vti nlmon bond_slave geneve bridge_slave macsec" for T in $TYPE do echo $T ip link show type $T done
竟然不属于这里边任意一个类型。。。。
虽然没有正面回答，但是看一下下面这个问题的答案，就能很好的理解了：
同时，也讲解了KVM的tap设备怎么可OVS协作，以及需要注意什么。
https://github.com/openvswitch/ovs/blob/master/Documentation/faq/issues.rst
Q: I created a tap device tap0, configured an IP address on it, and added it to a bridge, like this:
大概就是说，OVS的bridge和OVS的internal port是OVS单独实现的两种特殊设备。
报错：
[root@D128 BUILD_ovs]# ./bin/ovs-vsctl add-port br0 p0 ovs-vsctl: Error detected while setting up 'p0': could not open network device p0 (No such device). See ovs-vswitchd log for details. ovs-vsctl: The default log directory is "/root/BUILD_ovs/var/log/openvswitch". [root@D128 BUILD_ovs]#
要这样：
https://github.com/openvswitch/ovs-issues/issues/110
The port‘s name should be a exist interface use ifconfig to see, such as eth0. If you just want to use a virtual port name to make a test you should
specify the port's type like ovs-vsctl add-port br0 port0 -- set Interface port0 type=internal or ovs-vsctl set Interface port0 type=internal
[root@D128 BUILD_ovs]# ./bin/ovs-vsctl add-port br0 port0 -- set Interface port0 type=internal [root@D128 BUILD_ovs]# ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:0c:29:2f:cf:32 brd ff:ff:ff:ff:ff:ff 3: ovs-system: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000 link/ether 92:e5:c6:d2:ec:a2 brd ff:ff:ff:ff:ff:ff 4: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000 link/ether be:e8:bd:df:ff:41 brd ff:ff:ff:ff:ff:ff 5: port0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000 link/ether f6:cb:c2:69:fc:e0 brd ff:ff:ff:ff:ff:ff [root@D128 BUILD_ovs]# ./bin/ovs-vsctl show 528b5679-22e8-484b-947b-4499959dc341 Bridge "br0" Port "port0" Interface "port0" type: internal Port "br0" Interface "br0" type: internal ovs_version: "2.7.0" [root@D128 BUILD_ovs]#
查看br0，port0这两个设备。
[root@D128 BUILD_ovs]# ethtool -i br0 driver: openvswitch version: firmware-version: expansion-rom-version: bus-info: supports-statistics: no supports-test: no supports-eeprom-access: no supports-register-dump: no supports-priv-flags: no [root@D128 BUILD_ovs]# ethtool -i port0 driver: openvswitch version: firmware-version: expansion-rom-version: bus-info: supports-statistics: no supports-test: no supports-eeprom-access: no supports-register-dump: no supports-priv-flags: no [root@D128 BUILD_ovs]#
增加namespace
[root@D128 BUILD_ovs]# ip netns add ns0 [root@D128 BUILD_ovs]# ip link set port0 netns ns0
[root@D128 BUILD_ovs]# ip netns exec ns0 ip addr add 192.168.1.100/24 dev port0 [root@D128 BUILD_ovs]# ip netns exec ns0 ifconfig port0 promisc up
查看：
[root@D128 BUILD_ovs]# ./bin/ovs-ofctl show br0 OFPT_FEATURES_REPLY (xid=0x2): dpid:0000bee8bddfff41 n_tables:254, n_buffers:0 capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst 2(port0): addr:00:00:00:00:0c:e1 config: PORT_DOWN state: LINK_DOWN speed: 0 Mbps now, 0 Mbps max LOCAL(br0): addr:be:e8:bd:df:ff:41 config: PORT_DOWN state: LINK_DOWN speed: 0 Mbps now, 0 Mbps max OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0 [root@D128 BUILD_ovs]# ./bin/ovs-dpctl show system@ovs-system: lookups: hit:174 missed:44 lost:0 flows: 0 masks: hit:263 total:0 hit/pkt:1.21 port 0: ovs-system (internal) port 1: br0 (internal) port 2: port0 (internal) [root@D128 BUILD_ovs]#
[root@D128 BUILD_ovs]# ip addr add 192.168.1.101/24 dev br0 [root@D128 BUILD_ovs]# ip link set br0 up
现在两个namespace可以通过br0 互通了。
增加一个of规则
[root@D128 BUILD_ovs]# ./bin/ovs-ofctl add-flow br0 "priority=1 idle_timeout=0, in_port=2,actions=mod_nw_src:9.181.137.1,normal" [root@D128 BUILD_ovs]# ./bin/ovs-ofctl show br0 OFPT_FEATURES_REPLY (xid=0x2): dpid:0000bee8bddfff41 n_tables:254, n_buffers:0 capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst 2(port0): addr:00:00:00:00:0c:e1 config: PORT_DOWN state: LINK_DOWN speed: 0 Mbps now, 0 Mbps max LOCAL(br0): addr:be:e8:bd:df:ff:41 config: 0 state: 0 speed: 0 Mbps now, 0 Mbps max OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0 [root@D128 BUILD_ovs]# ./bin/ovs-
抓包可以看见，原地址已经被修改为9.181.137.1
[root@D128 BUILD_ovs]# tcpdump -i br0 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on br0, link-type EN10MB (Ethernet), capture size 262144 bytes 11:39:00.988146 IP 9.181.137.1 > localhost: ICMP echo request, id 3101, seq 271, length 64 11:39:01.988227 IP 9.181.137.1 > localhost: ICMP echo request, id 3101, seq 272, length 64 11:39:02.988113 IP 9.181.137.1 > localhost: ICMP echo request, id 3101, seq 273, length 64 11:39:03.988133 IP 9.181.137.1 > localhost: ICMP echo request, id 3101, seq 274, length 64
暂时先到这。作为一个初步了解。
-------------------------------------------------- update @ 2018-03-30 20：11 -----------------------------------
在OVS port上抓包。
把port流量镜像出来。
[root@vrouter-ovs ~]# ip link add dev mirror type dummy [root@vrouter-ovs ~]# ip link set mirror up
[root@dr-lb ~]# ovs-vsctl add-port ovs-br0 mirror
[root@vrouter-ovs ~]# ovs-vsctl -- set Bridge br-tun mirror=@mi -- --id=@pmirror get Port mirror -- --id=@patch get Port tun-to-int -- --id=@mi create Mirror name=mymi select-dst-port=@patch select-src-port=@patch output-port=@pmirror [root@vrouter-ovs ~]# tcpdump -i mirror -nn
查看和删除mirror
# ovs-vsctl list Mirror
# ovs-vsctl clear bridge ovsbr0 mirrors
ovs-vsctl set Bridge ovs-br0 mirrors=@mi -- --id=@pmirror get Port mirror-br0 -- --id=@patch get port vxlanclient0 -- --id=@mi create Mirror name=mymi select-dst-port=@patch select-src-port=@patch output-port=@pmirror