docker实现跨宿主机的容器之间网络互联
背景：最近闲来无事，想到之前开发提出的问题不用k8s那套网络插件如何实现跨宿主机的容器之间网络互联，顺便复习下iptables知识点。
docker实现跨宿主机的容器之间网络互联
- 一. 环境介绍
- 二. docker跨主机互联实现说明
- 三. 修改docker0网桥网段
-
- 3.1 A宿主机10.1.10.113
- 3.2 B宿主机10.1.10.114
- 四. 写到最后：随着时间推移这篇文章访问量、收藏数急剧增加，也希望小伙伴们动动宝贵的小手点点赞，日行一善，等这段时间忙完我会更新kubernetes系列，把一些实用的案例一一分享出来!
一. 环境介绍
两台centos8.2的虚拟机以及harbor仓库的镜像
宿主机A：ip 10.1.10.113
宿主机B：ip 10.1.10.114
二. docker跨主机互联实现说明
跨主机互联是说A宿主机的容器可以访问B主机上的容器，但是前提是保证各宿主机之间的网络是可以相互通信的，然后各容器才可以通过宿主机访问到对方的容器。
实现原理: 是在宿主机做一个网络路由就可以实现A宿主机的容器访问B主机的容器的目的
三. 修改docker0网桥网段
3.1 A宿主机10.1.10.113
设置docker网桥网段为192.168.100.1
systemctl restart docker
docker login 10.1.10.15
docker pull 10.1.10.15/syimage/centos8.2:v2
docker run -itd --restart=always --name=vm01 --privileged 10.1.10.15/syimage/centos8.2:v2
添加静态路由和iptables规则
在各宿主机添加静态路由，网关指向对方宿主机的IP
route add -net 192.168.200.0/24 gw 10.1.10.114
iptables -A FORWARD -s 10.0.0.0/24 -j ACCEPT
#或者修改FORWARD默认规则
iptables -P FORWARD ACCEPT
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.1.10.1 0.0.0.0 UG 100 0 0 ens32
10.1.10.0 0.0.0.0 255.255.255.0 U 100 0 0 ens32
192.168.100.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
192.168.200.0 10.1.10.114 255.255.255.0 UG 0 0 0 ens32
测试跨宿主机之间容器互联
docker exec -it vm01 ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.100.2 netmask 255.255.255.0 broadcast 192.168.100.255
ether 02:42:c0:a8:64:02 txqueuelen 0 (Ethernet)
RX packets 36 bytes 25292 (24.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 45 bytes 5310 (5.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@shudun ~]# docker exec -it vm01 ping 192.168.200.2
PING 192.168.200.2 (192.168.200.2) 56(84) bytes of data.
64 bytes from 192.168.200.2: icmp_seq=1 ttl=62 time=0.907 ms
64 bytes from 192.168.200.2: icmp_seq=2 ttl=62 time=0.678 ms
^C
--- 192.168.200.2 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 2ms
rtt min/avg/max/mdev = 0.678/0.792/0.907/0.117 ms
3.2 B宿主机10.1.10.114
设置docker网桥网段为192.168.200.1
systemctl restart docker
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.1.10.1 0.0.0.0 UG 100 0 0 ens32
10.1.10.0 0.0.0.0 255.255.255.0 U 100 0 0 ens32
192.168.100.0 10.1.10.113 255.255.255.0 UG 0 0 0 ens32
192.168.200.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
docker login 10.1.10.15
docker pull 10.1.10.15/syimage/centos8.2:v2
docker run -itd --restart=always --name=vm01 --privileged 10.1.10.15/syimage/centos8.2:v2
添加静态路由和iptables规则
在各宿主机添加静态路由，网关指向对方宿主机的IP
route add -net 192.168.100.0/24 gw 10.1.10.113
iptables -A FORWARD -s 10.0.0.0/24 -j ACCEPT
#或者修改FORWARD默认规则
iptables -P FORWARD ACCEPT
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.1.10.1 0.0.0.0 UG 100 0 0 ens32
10.1.10.0 0.0.0.0 255.255.255.0 U 100 0 0 ens32
192.168.100.0 10.1.10.113 255.255.255.0 UG 0 0 0 ens32
192.168.200.0 0.0.0.0 255.255.255.0 U 0 0 0 docker0
测试跨宿主机之间容器互联
docker exec -it vm01 ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.200.2 netmask 255.255.255.0 broadcast 192.168.200.255
ether 02:42:c0:a8:c8:02 txqueuelen 0 (Ethernet)
RX packets 36 bytes 25280 (24.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 45 bytes 5322 (5.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@shudun ~]# docker exec -it vm01 ping 192.168.100.2
PING 192.168.100.2 (192.168.100.2) 56(84) bytes of data.
64 bytes from 192.168.100.2: icmp_seq=1 ttl=62 time=0.704 ms
64 bytes from 192.168.100.2: icmp_seq=2 ttl=62 time=0.650 ms
^C
--- 192.168.100.2 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 51ms
rtt min/avg/max/mdev = 0.650/0.677/0.704/0.027 ms
最后宿主机A的容器vm01访问宿主机B容器vm02，同时在宿主机B上tcpdump抓包观察
