參考https://www.cnblogs.com/CloudMan6/p/7305989.html 今天開始學習?overlay?網絡跨主機通信的原理 ? root@host01:~# ufw allow 4789/udp root@host01:~# ufw status numbered Status: active To?????????????????????????Action??????From --?????????????????????????------??????---- [ 1] 22?????????????????????????ALLOW IN????Anywhere?????????????????? [ 2] 2376???????????????????????ALLOW IN????Anywhere?????????????????? [ 3] 4789/udp???????????????????ALLOW IN????Anywhere?? root@host01:~#?docker run -itd --name bbox1 --network ov_net1 busybox root@host01:~# docker exec bbox1 ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 8: eth0@if9: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1450 qdisc noqueue link/ether 02:42:0a:00:00:02 brd ff:ff:ff:ff:ff:ff inet 10.0.0.2/24 brd 10.0.0.255 scope global eth0 valid_lft forever preferred_lft forever 11: eth1@if12: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue link/ether 02:42:ac:12:00:02 brd ff:ff:ff:ff:ff:ff inet 172.18.0.2/16 brd 172.18.255.255 scope global eth1 valid_lft forever preferred_lft forever ? root@host01:~# docker exec bbox1 ping -c 2??bbox2 PING bbox2 (10.0.0.3): 56 data bytes 64 bytes from 10.0.0.3: seq=0 ttl=64 time=0.348 ms 64 bytes from 10.0.0.3: seq=1 ttl=64 time=0.440 ms --- bbox2 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.348/0.394/0.440 ms root@host01:~# ln -s /var/run/docker/netns /var/run/netns root@host01:~# ip netns a8d468c12df8 (id: 1) 1-609020e03f (id: 0) root@host01:~# ip netns exec 1-609020e03f brctl show bridge name????bridge id????????STP enabled????interfaces br0????????8000.0af427b2de24????no????????veth0 vxlan0 root@host01:~# ip netns exec 1-609020e03f ip -d l show vxlan0 7: vxlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue master br0 state UNKNOWN mode DEFAULT group default link/ether 1a:3d:67:93:45:5d brd ff:ff:ff:ff:ff:ff link-netnsid 0 promiscuity 1 vxlan id 256 srcport 0 0 dstport 4789 proxy l2miss l3miss ageing 300 bridge_slave state forwarding priority 32 cost 100 hairpin off guard off root_block off fastleave off learning on flood on addrgenmode eui64 -------------------------------------------------------------------------------------------------------- ? root@host02:~# ufw allow 4789/udp root@host02:~# ufw status numbered Status: active To?????????????????????????Action??????From --?????????????????????????------??????---- [ 1] 22?????????????????????????ALLOW IN????Anywhere?????????????????? [ 2] 2376???????????????????????ALLOW IN????Anywhere?????????????????? [ 3] 4789/udp???????????????????ALLOW IN????Anywhere?????????????????? root@host02:~# docker run -itd --name bbox2 --network ov_net1 busybox root@host02:~# docker exec bbox2 ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 8: eth0@if9: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1450 qdisc noqueue link/ether 02:42:0a:00:00:03 brd ff:ff:ff:ff:ff:ff inet 10.0.0.3/24 brd 10.0.0.255 scope global eth0 valid_lft forever preferred_lft forever 11: eth1@if12: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue link/ether 02:42:ac:12:00:02 brd ff:ff:ff:ff:ff:ff inet 172.18.0.2/16 brd 172.18.255.255 scope global eth1 valid_lft forever preferred_lft forever root@host02:~# docker exec bbox2 ping -c 2 bbox1 PING bbox1 (10.0.0.2): 56 data bytes 64 bytes from 10.0.0.2: seq=0 ttl=64 time=0.382 ms 64 bytes from 10.0.0.2: seq=1 ttl=64 time=0.353 ms --- bbox1 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 0.353/0.367/0.382 ms root@host02:~# ln -s /var/run/docker/netns /var/run/netns root@host02:~# ip netns 9e3d32ba4934 (id: 1) 1-609020e03f (id: 0) root@host02:~# ip netns exec 1-609020e03f brctl show bridge name????bridge id????????STP enabled????interfaces br0????????8000.1ad722007738????no????????veth0 vxlan0 root@host02:~# ip netns exec 1-609020e03f ip -d l show vxlan0 7: vxlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue master br0 state UNKNOWN mode DEFAULT group default link/ether 1a:d7:22:00:77:38 brd ff:ff:ff:ff:ff:ff link-netnsid 0 promiscuity 1 vxlan id 256 srcport 0 0 dstport 4789 proxy l2miss l3miss ageing 300 bridge_slave state forwarding priority 32 cost 100 hairpin off guard off root_block off fastleave off learning on flood on addrgenmode eui64 以上實驗，可見overlay網絡中的容器可以直接通信，即使兩個容器不在同一臺host上，且支持?docker?dns docker?會為每個?overlay?網絡創建一個獨立的?network?namespace ，其中會有一個?linux?bridge?br0 ，endpoint?還是由?veth?pair?實現，一端連接到容器中（即eth0），另一端連接到namespace的br0上。 br0?除了連接所有的endpoint，還會連接一個vxlan?設備，用于與其他host建立vxlan?tunnel。容器之間的數據就是通過這個tunnel通信的。 要查看overlay?網絡的namespace?可以在?host01?和?host02?上執行?ipnetns （需要先執行ln -s /var/run/docker/netns /var/run/netns），可以看到兩個?host上有一個相同名稱的namespace，這就是 ov_net1?的namespace，可以在該namespace中查看br0設備，還可以在該namespace中查看到具有相同?id?的vxlan

轉載于:https://www.cnblogs.com/www1707/p/10556644.html

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