docker网络配置过程详解介绍
飘飘悠悠 · 413浏览 · 发布于2021-12-09
大家好，本篇文章主要讲的是docker网络配置过程详解介绍，感兴趣的同学赶快来看一看吧，对你有帮助的话记得收藏一下，方便下次浏览
Linux内核实现名称空间的创建
ip netns命令
可以借助ip netns命令来完成对 Network Namespace 的各种操作。ip netns命令来自于iproute安装包，一般系统会默认安装，如果没有的话，请自行安装。
注意：ip netns命令修改网络配置时需要 sudo 权限。
可以通过ip netns命令完成对Network Namespace 的相关操作，可以通过ip netns help查看命令帮助信息：
[root@master ~]# ip netns help Usage: ip netns list ip netns add NAME ip netns attach NAME PID ip netns set NAME NETNSID ip [-all] netns delete [NAME] ip netns identify [PID] ip netns pids NAME ip [-all] netns exec [NAME] cmd ... ip netns monitor ip netns list-id [target-nsid POSITIVE-INT] [nsid POSITIVE-INT] NETNSID := auto | POSITIVE-INT [root@master ~]# ip netns list [root@master ~]# ip netns add ns0 [root@master ~]# ip netns list ns0 [root@master ~]# ls /var/run/netns ns0 [root@master ~]# ip netns add ns0 Cannot create namespace file "/var/run/netns/ns0": File exists [root@master ~]# touch /var/run/netns/ns1 [root@master ~]# ip netns list Error: Peer netns reference is invalid. Error: Peer netns reference is invalid. ns1 ns0 [root@master ~]# ip netns del ns1 [root@master ~]# ip netns list ns0
操作Network Namespace
ip命令提供了ip netns exec子命令可以在对应的 Network Namespace 中执行命令。
查看新创建 Network Namespace 的网卡信息
[root@master ~]# ip netns exec ns0 ip addr 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 可以看到，新创建的Network Namespace中会默认创建一个lo回环网卡，此时网卡处于关闭状态。此时，尝试去 ping 该lo回环网卡，会提示Network is unreachable [root@master ~]# ip netns exec ns0 ping 127.0.0.1 connect: 网络不可达 通过下面的命令启用lo回环网卡 [root@master ~]# ip netns exec ns0 ip link set lo up [root@master ~]# ip netns exec ns0 ping 127.0.0.1 PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. 64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.024 ms 64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.019 ms
转移设备
我们可以在不同的 Network Namespace 之间转移设备（如veth）。由于一个设备只能属于一个 Network Namespace ，所以转移后在这个 Network Namespace 内就看不到这个设备了。
其中，veth设备属于可转移设备，而很多其它设备（如lo、vxlan、ppp、bridge等）是不可以转移的。
veth pair
veth pair 全称是 Virtual Ethernet Pair，是一个成对的端口，所有从这对端口一 端进入的数据包都将从另一端出来，反之也是一样。
引入veth pair是为了在不同的 Network Namespace 直接进行通信，利用它可以直接将两个 Network Namespace 连接起来。
创建veth pair
[root@master ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 00:0c:29:d7:ce:07 brd ff:ff:ff:ff:ff:ff inet 192.168.197.131/24 brd 192.168.197.255 scope global dynamic noprefixroute ens33 valid_lft 1522sec preferred_lft 1522sec inet6 fe80::1f2f:a9f9:78a7:7cc/64 scope link noprefixroute valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000 link/ether 52:54:00:f1:42:78 brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master virbr0 state DOWN group default qlen 1000 link/ether 52:54:00:f1:42:78 brd ff:ff:ff:ff:ff:ff 5: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default link/ether 02:42:b8:38:aa:7d brd ff:ff:ff:ff:ff:ff inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0 valid_lft forever preferred_lft forever inet6 fe80::42:b8ff:fe38:aa7d/64 scope link valid_lft forever preferred_lft forever 7: veth2672252@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default link/ether ca:56:6c:07:de:af brd ff:ff:ff:ff:ff:ff link-netnsid 0 inet6 fe80::c856:6cff:fe07:deaf/64 scope link valid_lft forever preferred_lft forever [root@master ~]# ip link add type veth [root@master ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 00:0c:29:d7:ce:07 brd ff:ff:ff:ff:ff:ff inet 192.168.197.131/24 brd 192.168.197.255 scope global dynamic noprefixroute ens33 valid_lft 1499sec preferred_lft 1499sec inet6 fe80::1f2f:a9f9:78a7:7cc/64 scope link noprefixroute valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000 link/ether 52:54:00:f1:42:78 brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master virbr0 state DOWN group default qlen 1000 link/ether 52:54:00:f1:42:78 brd ff:ff:ff:ff:ff:ff 5: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default link/ether 02:42:b8:38:aa:7d brd ff:ff:ff:ff:ff:ff inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0 valid_lft forever preferred_lft forever inet6 fe80::42:b8ff:fe38:aa7d/64 scope link valid_lft forever preferred_lft forever 7: veth2672252@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default link/ether ca:56:6c:07:de:af brd ff:ff:ff:ff:ff:ff link-netnsid 0 inet6 fe80::c856:6cff:fe07:deaf/64 scope link valid_lft forever preferred_lft forever 10: veth0@veth1: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether a2:0f:68:39:2c:fd brd ff:ff:ff:ff:ff:ff 11: veth1@veth0: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether e6:e9:55:96:60:35 brd ff:ff:ff:ff:ff:ff
可以看到，此时系统中新增了一对veth pair，将veth0和veth1两个虚拟网卡连接了起来，此时这对 veth pair 处于”未启用“状态。
实现Network Namespace间通信
[root@master ~]# ip netns list ns0 [root@master ~]# ip netns add ns1 [root@master ~]# ip link set veth0 netns ns0 [root@master ~]# ip link set veth1 netns ns1 [root@master ~]# ip netns exec ns0 ip link set veth0 up [root@master ~]# ip netns exec ns0 ip addr add 192.168.2.1/24 dev veth0 [root@master ~]# ip netns exec ns1 ip link set veth1 up [root@master ~]# ip netns exec ns1 ip addr add 192.168.2.2/24 dev veth1 [root@master ~]# ip netns exec ns0 ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 10: veth0@if11: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether a2:0f:68:39:2c:fd brd ff:ff:ff:ff:ff:ff link-netns ns1 inet 192.168.2.1/24 scope global veth0 valid_lft forever preferred_lft forever inet6 fe80::a00f:68ff:fe39:2cfd/64 scope link valid_lft forever preferred_lft forever [root@master ~]# ip netns exec ns1 ip a 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 11: veth1@if10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether e6:e9:55:96:60:35 brd ff:ff:ff:ff:ff:ff link-netns ns0 inet 192.168.2.2/24 scope global veth1 valid_lft forever preferred_lft forever inet6 fe80::e4e9:55ff:fe96:6035/64 scope link valid_lft forever preferred_lft forever [root@master ~]# ip netns exec ns1 ping 192.168.2.1 PING 192.168.2.1 (192.168.2.1) 56(84) bytes of data. 64 bytes from 192.168.2.1: icmp_seq=1 ttl=64 time=0.037 ms 64 bytes from 192.168.2.1: icmp_seq=2 ttl=64 time=0.028 ms
可以看到，veth pair成功实现了两个不同Network Namespace之间的网络交互。
veth设备重命名
[root@master ~]# ip netns exec ns0 ip link set veth0 down [root@master ~]# ip netns exec ns0 ip link set veth0 down [root@master ~]# ip netns exec ns0 ip link set veth0 down [root@master ~]# ip netns exec ns0 ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 10: veth0@if11: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN group default qlen 1000 link/ether a2:0f:68:39:2c:fd brd ff:ff:ff:ff:ff:ff link-netns ns1 inet 192.168.2.1/24 scope global veth0 valid_lft forever preferred_lft forever [root@master ~]# ip netns exec ns1 ip link set veth1 down [root@master ~]# ip netns exec ns1 ip link set dev veth1 name eth0 [root@master ~]# ip netns exec ns1 ip link set eth0 [root@master ~]# ip netns exec ns1 ip a 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 11: eth0@if10: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN group default qlen 1000 link/ether e6:e9:55:96:60:35 brd ff:ff:ff:ff:ff:ff link-netns ns0 inet 192.168.2.2/24 scope global eth0 valid_lft forever preferred_lft forever
四种网络模式配置
bridge模式
[root@master ~]# docker pull busybox Using default tag: latest latest: Pulling from library/busybox 3aab638df1a9: Pull complete Digest: sha256:52817dece4cfe26f581c834d27a8e1bcc82194f914afe6d50afad5a101234ef1 Status: Downloaded newer image for busybox:latest docker.io/library/busybox:latest [root@master ~]# docker run -it --name b1 --rm busybox # --rm 删除或停止容器后自动销毁容器 / # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000 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 12: eth0@if13: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff inet 172.17.0.3/16 brd 172.17.255.255 scope global eth0 valid_lft forever preferred_lft forever / # exit [root@master ~]# docker run -it --name b1 --network bridge --rm busybox / # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000 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 14: eth0@if15: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff inet 172.17.0.3/16 brd 172.17.255.255 scope global eth0 valid_lft forever preferred_lft forever / # exit
none模式
[root@master ~]# docker run -it --name b2 --rm --network none busybox / # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000 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 / # exit 使用none模式，Docker容器拥有自己的Network Namespace，但是，并不为Docker容器进行任何网络配置。也就是说，这个Docker容器没有网卡、IP、路由等信息。需要我们自己为Docker容器添加网卡、配置IP等。
container模式
[root@master ~]# docker run -it --name b3 --rm busybox / # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000 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 16: eth0@if17: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff inet 172.17.0.3/16 brd 172.17.255.255 scope global eth0 valid_lft forever preferred_lft forever 新开一个终端 [root@master ~]# docker run -it --name b4 --rm --network container:b3 busybox / # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000 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 16: eth0@if17: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue link/ether 02:42:ac:11:00:03 brd ff:ff:ff:ff:ff:ff inet 172.17.0.3/16 brd 172.17.255.255 scope global eth0 valid_lft forever preferred_lft forever 在b3上创建一个文件 / # ls bin dev etc home proc root sys tmp usr var / # mkdir yy 在b4上查看 / # ls bin dev etc home proc root sys tmp usr var 在b3上创建网站 / # echo "aaa." > bbb/index.html / # httpd -h bbb/ / # netstat -antl Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 :::80 :::* LISTE # 在b4上访问 / # wget -qO - 172.17.0.2 aaa / # # 由此可见，container模式下的容器间关系就相当于一台主机上的两个不同进程
这个模式指定新创建的容器和已经存在的一个容器共享一个 Network Namespace，而不是和宿主机共享。新创建的容器不会创建自己的网卡，配置自己的 IP，而是和一个指定的容器共享 IP、端口范围等。同样，两个容器除了网络方面，其他的如文件系统、进程列表等还是隔离的。两个容器的进程可以通过 lo 网卡设备通信。
host模式
启动容器时直接指明模式为host
[root@master ~]# docker run -it --name b5 --rm --network host busybox / # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel qlen 1000 link/ether 00:0c:29:d7:ce:07 brd ff:ff:ff:ff:ff:ff inet 192.168.197.131/24 brd 192.168.197.255 scope global dynamic noprefixroute ens33 valid_lft 1741sec preferred_lft 1741sec inet6 fe80::1f2f:a9f9:78a7:7cc/64 scope link noprefixroute valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue qlen 1000 link/ether 52:54:00:f1:42:78 brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master virbr0 qlen 1000 link/ether 52:54:00:f1:42:78 brd ff:ff:ff:ff:ff:ff 5: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue link/ether 02:42:b8:38:aa:7d brd ff:ff:ff:ff:ff:ff inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0 valid_lft forever preferred_lft forever inet6 fe80::42:b8ff:fe38:aa7d/64 scope link valid_lft forever preferred_lft forever 7: veth2672252@if6: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue master docker0 link/ether ca:56:6c:07:de:af brd ff:ff:ff:ff:ff:ff inet6 fe80::c856:6cff:fe07:deaf/64 scope link valid_lft forever preferred_lft forever / # mkdir www / # echo "ccc" > www/index.html / # httpd -h www/ / # [root@master ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 00:0c:29:d7:ce:07 br
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