Docker 网络基础原理

网络基础

网络分层模型

公有IP和私有IP

Public IP：互联网上的唯一标识，可以访问internet

Private IP：不可在互联网上使用，仅供机构内部使用

A类10.0.0.0--10.255.255.255(10.0.0.0/8)

B类172.16.0.0--172.31.255.255(172.16.0.0/12)

C类192.168.0.0--192.168.255.255(192.168.0.0/16)

网络地址转换NAT

Ping和telnet

Ping(ICMP)：验证IP的可达性

Linux 网络命名空间

Linux Network Namespace

查看当前网络命名空间
[root@docker-node1 vagrant]# ip netns list
添加网络命名空间
[root@docker-node1 vagrant]# ip netns add test1
[root@docker-node1 vagrant]# ip netns add test2
[root@docker-node1 vagrant]# ip netns list
test2
test1
[root@docker-node1 vagrant]# sudo ip netns exec test1 ip link
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULTlink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
[root@docker-node1 vagrant]# sudo ip netns exec test1 ip link set dev lo up
[root@docker-node1 vagrant]# sudo ip netns exec test1 ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULTlink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00[root@docker-node2 vagrant]# ip netns exec test1 ip link
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULTlink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
[root@docker-node2 vagrant]# sudo ip link set veth-test1 netns test1
[root@docker-node2 vagrant]# ip netns exec test1 ip link
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULTlink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
6: veth-test1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000link/ether 36:2d:2a:23:8e:af brd ff:ff:ff:ff:ff:ff

添加了一个test2的网络命名空间
[root@docker-node2 vagrant]# ip netns add test2
绑定到veth-test2的设备
[root@docker-node2 vagrant]# sudo ip link set veth-test2 netns test2
查看命名空间的ip link
[root@docker-node2 vagrant]# ip netns exec test2 ip link
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULTlink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
5: veth-test2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT qlen 1000link/ether 2e:00:77:8a:33:57 brd ff:ff:ff:ff:ff:ff给网络命名空间添加ip并绑定
sudo ip netns exec test1 ip addr add 192.168.1.1/24 dev veth-testl
sudo ip netns exec test2 ip addr add 192.168.1.2/24 dev veth-test2将两个网络命名空间绑定的ip设备启动
sudo ip netns exec test1 ip link set dev veth-testl up
sudo ip netns exec test2 ip link set dev veth-test2 up查看完整的命名空间ip信息
[root@docker-node2 vagrant]# ip netns exec test1 ip a
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWNlink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
6: veth-testl: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000link/ether 36:2d:2a:23:8e:af brd ff:ff:ff:ff:ff:ffinet 192.168.1.1/24 scope global veth-testlvalid_lft forever preferred_lft foreverinet6 fe80::342d:2aff:fe23:8eaf/64 scope linkvalid_lft forever preferred_lft forever
[root@docker-node2 vagrant]# ip netns exec test2 ip a
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWNlink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
5: veth-test2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000link/ether 2e:00:77:8a:33:57 brd ff:ff:ff:ff:ff:ffinet 192.168.1.2/24 scope global veth-test2valid_lft forever preferred_lft foreverinet6 fe80::2c00:77ff:fe8a:3357/64 scope linkvalid_lft forever preferred_lft forever测试命名空间的 互通性 ping
[root@docker-node2 vagrant]# ip netns exec test2 ping 192.168.1.1
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.050 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.110 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=0.202 ms
64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=0.052 ms
64 bytes from 192.168.1.1: icmp_seq=5 ttl=64 time=0.040 ms

Docker Network

单机网络Bridge Network
Host Network
None Network多机网络：overlay Network

Bridge 模式

每个容器之间有独立的命名空间(ip)，相互之间可以ping 通，

Docker Bridge0 在宿主机上桥接出来的一块命名空间，通常为 172.17.0.2，里面容器的ip一般在该网段随机分布。除非容器暴露了外面的，否则外面宿主机不能访问

[root@docker-node2 ~]# sudo docker run -d --name test1 busybox /bin/sh -c "while true;do sleep 3600;done"
8f7cbad560db6d4c604395f3ee16c15d6fc4073e3010134e2520aed780b6198d

[root@docker-node2 ~]# docker exec test1 ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueuelink/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00inet 127.0.0.1/8 scope host lovalid_lft forever preferred_lft forever
9: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueuelink/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ffinet 172.17.0.2/16 brd 172.17.255.255 scope global eth0valid_lft forever preferred_lft forever

查看网桥
brctl show

新创建一个容器，新增了一个命名空间

Bridge Network 网桥

查看网桥

新创建一个容器后，会在网桥上有一个新的接口

通信

在docker0网桥上面创建的容器关联

[vagrantedocker-node1～]# sudo docker run -d --name test2 --link test1 busybox /bin/sh -c "while true;do sleep 3600;done"
test2 link test1  容器test2 link 容器test1
2 --> 1 ping 通
1 --> 2 ping 不通创建网桥
[root@docker-node2 ~]# docker network create -d bridge my-bridge
d7b1a39ddd6cd0fff8a7f2ff57a3391e9ac68f8bf09b05460f7d1200c712bc78
[root@docker-node2 ~]# brctl show
bridge name     bridge id               STP enabled     interfaces
br-d7b1a39ddd6c         8000.0242ed73f4fa       no
docker0         8000.02420e28dc52       no              veth8bb0084vethced44cb


[root@docker-node2 ~]# docker network ls
NETWORK ID          NAME                DRIVER              SCOPE
0e7556320fdd        bridge              bridge              local
0b32df326904        host                host                local
d7b1a39ddd6c        my-bridge           bridge              local
e2db49527111        none                null                local
重新创建test2

[root@docker-node2 ~]#  sudo docker run -d --name test2 --network my-bridge busybox /bin/sh -c "while true;do sleep 3600;done"
7eb76c6ca9f6123811fc75cae03e571f669b308c2b6bad0cfbdd598508629f0d
[root@docker-node2 ~]# brctl show
bridge name     bridge id               STP enabled     interfaces
br-d7b1a39ddd6c  8000.0242ed73f4fa       no              vethee72a47
docker0         8000.02420e28dc52       no              veth8bb0084vethced44cb

docker network inspect my-bridge

sudo docker run -d --name test3 --network my-bridge busybox /bin/sh -c "while true;do sleep 3600;done"test2 和 test 3 在同一个网桥my-bridge (自己创建的)，可以通过名称ping

在test 2测试ping test3

docker inspect my-bridge

总结

docker network connect my-bridge test1
- tes2和test 1在docker 默认创建的bridge上
- 但是互相只能通过ip来ping通、不能通过名字
自己创建的bridge 能够解决互相ip，名字都ping通

容器的端口映射

docker run --name web -d -p 80:80 nginx
Container Port Map 端口映射

host & none 模式

1. none 没有ip，只有宿主可以访问

[vagrant@docker-node1～]$ sudo docker run -d --name test1 --network none busybox /bin/sh -c "while true;do sleep 3600;done"
da2143722efb01827070a4aa5ce52857f9269f5ed20f65f4cb39977d39141913

谁都不能访问，只能 sudo docker exec -it test1 /bin/sh

2. host 共享主机的网络

[vagrant@docker-node1 ~]$ sudo docker run -d --name test1 --network host busybox /bin/sh -c "while true;do sleep 3600;done"
18e175e07b5e15c941f848fa5d4105357d70dd0f03f8bdb55791c0997875074b

容器内部网络跟宿主机一样