It is found that eth0 is one end of a veth device.

Veth addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 Link/ether 86:41:d0:e3:0c:65 brd ff:ff:ff:ff:ff:ff link-netnsid 0 promiscuity 0 You can see that the vethef2d98bc device master is on the cni0 bridge.Įnter the network namespace of Pod A again to check the type of eth0 network card in Pod A ~]# ip -d link show eth0ģ: mtu 1500 qdisc noqueue state UP mode DEFAULT group default Let's first look at the interfaces that exist on the cni0 bridge ~]# bridge linkĢ270: vethef2d98bc state UP mtu 1500 master cni0 state forwarding priority 32 cost 2 It can be found that 10.10.2.1 is the address of cni0 bridge.

How is eth0 connected to the device 10.10.2.1?Įxit the network namespace of Pod A and view the IP address of the device on the host through the command ~]# ip aĥ: cni0: mtu 1500 qdisc noqueue state UP group default qlen 1000.

Pod A's packets are sent to 10.10.2.1 through eth0. First, enter the network namespace of Pod A to view the route of Pod A ~]# ip routeġ0.10.2.0/24 dev eth0 proto kernel scope link src 10.10.2.238 We started from Pod A to explore networking methods. The main network facilities involved in the flannel host GW mode are: Corresponding plug-ins need to be installed in the public cloud environment, such as Alibaba cloud CCM. This requires that all nodes in the cluster must be in the same network in this mode. In the host GW mode, the cross node network communication needs to be realized through the routing table on the node, so the host hosts of both sides of the communication must be able to route directly.

Flannel's host GW mode is a pure three-layer network interworking scheme, and the mutual access between pods is realized by routing.

What is kubernetes flannel