docker网络配置过程详解介绍

  • Z时代
  • 2024-01-10
  • 分类：IT

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。

在这里插入图片描述

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 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 1730sec preferred_lft 1730sec
    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 ~]# curl 192.168.197.131
ccc

容器的常用操作

[root@master ~]# docker run -it --name b6 --rm busybox
/ # hostname
ef156ee78b70
/ # exit
[root@master ~]# docker run -it --name b6 --hostname yanghaixx busybox
/ # hostname 
yanghaixx
/ # cat /etc/hosts
127.0.0.1       localhost
::1     localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
172.17.0.3      yanghaixx
/ # cat /etc/resolv.conf 
# Generated by NetworkManager
search localdomain
nameserver 192.168.197.2
/ # ping baidu.com
PING baidu.com (220.181.38.148): 56 data bytes
64 bytes from 220.181.38.148: seq=0 ttl=127 time=25.224 ms
64 bytes from 220.181.38.148: seq=1 ttl=127 time=24.795 ms
[root@master ~]# docker run -it --rm  --name b7 --dns 8.8.8.8 --hostname yanghaixx busybox
/ # cat /etc/resolv.conf 
search localdomain
nameserver 8.8.8.8
/ # exit .
[root@master ~]# docker run -it --name b7 --rm --hostname yanghaixx --add-host baidu.com:0.0.0.0  busybox
/ # cat /etc/hosts
127.0.0.1       localhost
::1     localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
0.0.0.0 baidu.com
172.17.0.3      yanghaixx

端口映射

执行docker run的时候有个-p选项，可以将容器中的应用端口映射到宿主机中，从而实现让外部主机可以通过访问宿主机的某端口来访问容器内应用的目的。

-p选项能够使用多次，其所能够暴露的端口必须是容器确实在监听的端口。
-p选项的使用格式：
-p
将指定的容器端口映射至主机所有地址的一个动态端口
动态端口指的是随机端口，具体的映射结果可使用docker port命令查看。

[root@master ~]# docker run -d --name web1 --rm -p 80 yanghaixx/nginx:v2
62029a5977a06e07ab5b40c78ce60e9cc519364512bc2e6d5785afd7dc1e090f
[root@master ~]#  docker port web1
80/tcp -> 0.0.0.0:49153
80/tcp -> :::49153
[root@master ~]# curl 192.168.197.131:49153
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>

将容器端口映射到宿主机的指定端口

[root@master ~]# docker run -itd --name web2 --rm -p 2525:80 yanghaixx/nginx:v2
62a93a8ef40eec981b2d1682da92523027999991b0294782be38d4565b210ff8
[root@master ~]# docker port web2
80/tcp -> 0.0.0.0:2525
80/tcp -> :::2525
[root@master ~]# curl 192.168.197.131:2525
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>

自定义docker0桥的网络属性信息

自定义docker0桥的网络属性信息需要修改/etc/docker/daemon.json配置文件

[root@master ~]# vim /etc/docker/daemon.json
[root@master ~]# cat /etc/docker/daemon.json
{
        "registry-mirrors": ["https://q9u587gb.mirror.aliyuncs.com"]
        "bip": "192.168.2.1/24"
}
See "systemctl status docker.service" and "journalctl -xe" for details.
[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 1690sec preferred_lft 1690sec
    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: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:97:2a:95:42 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.1/24 brd 192.168.2.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:97ff:fe2a:9542/64 scope link 
       valid_lft forever preferred_lft forever

docker创建自定义桥

[root@master ~]# vim /etc/docker/daemon.json
[root@master ~]# cat /etc/docker/daemon.json
{
        "registry-mirrors": ["https://q9u587gb.mirror.aliyuncs.com"]
        "bip": "192.168.2.1/24"
}
See "systemctl status docker.service" and "journalctl -xe" for details.
[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 1690sec preferred_lft 1690sec
    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: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:97:2a:95:42 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.1/24 brd 192.168.2.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:97ff:fe2a:9542/64 scope link 
       valid_lft forever preferred_lft forever

使用新创建的自定义桥来创建容器：

[root@master ~]# docker run -itd --name web --network br0 --rm yanghaixx/nginx:v2
aec728f703567b36016cf09cde1ffd1036673d7c2d961cae0b81cd09721d5cb9
[root@master ~]# docker exec -it web /bin/bash
[root@aec728f70356 /]# 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
31: eth0@if32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:11:01:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.17.1.2/24 brd 172.17.1.255 scope global eth0
       valid_lft forever preferred_lft forever

再创建一个容器，使用默认的bridge桥：

[root@master ~]# docker run -itd --name web02 --rm luojiatian1904/nginx:v2
4ee412be6d20b96a18f0b6fc0062beefc2192d906b212134b362ec41be5144ff
[root@master ~]# docker exec -it web02 /bin/bash
[root@4ee412be6d20 /]# 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
33: eth0@if34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:c0:a8:02:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.2.2/24 brd 192.168.2.255 scope global eth0
       valid_lft forever preferred_lft forever
[root@4ee412be6d20 /]#

试想一下，此时的b2与b1能否互相通信？如果不能该如何实现通信

# 运行两个容器在不同网段
[root@master ~]# docker run -itd --name web --network br0 --rm yanghaixx/nginx:v2
aec728f703567b36016cf09cde1ffd1036673d7c2d961cae0b81cd09721d5cb9
[root@master ~]# docker exec -it web /bin/bash
[root@aec728f70356 /]# 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
31: eth0@if32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:11:01:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.17.1.2/24 brd 172.17.1.255 scope global eth0
       valid_lft forever preferred_lft forever
[root@master ~]# docker run -itd --name web02 --rm yanghaixx/nginx:v2
4ee412be6d20b96a18f0b6fc0062beefc2192d906b212134b362ec41be5144ff
[root@master ~]# docker exec -it web02 /bin/bash
[root@4ee412be6d20 /]# 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
33: eth0@if34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:c0:a8:02:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.2.2/24 brd 192.168.2.255 scope global eth0
       valid_lft forever preferred_lft forever
[root@master ~]# docker ps -a
CONTAINER ID   IMAGE                     COMMAND                  CREATED         STATUS         PORTS     NAMES
4ee412be6d20   luojiatian1904/nginx:v2   "/usr/local/nginx/sb…"   2 minutes ago   Up 2 minutes             web02
aec728f70356   luojiatian1904/nginx:v2   "/usr/local/nginx/sb…"   2 minutes ago   Up 2 minutes             web

将br0网络 (C1) 连接到c2(一个容器运行两个桥)

[root@master ~]# docker network connect  br0 aec728f70356(web容器ID)
[root@4ee412be6d20 /]# 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
33: eth0@if34: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:c0:a8:02:02 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.2.2/24 brd 192.168.2.255 scope global eth0
       valid_lft forever preferred_lft forever
35: eth1@if36: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:ac:11:01:03 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.17.1.3/24 brd 172.17.1.255 scope global eth1
       valid_lft forever preferred_lft forever
[root@4ee412be6d20 /]# ping 172.17.1.2
PING 172.17.1.2 (172.17.1.2) 56(84) bytes of data.
64 bytes from 172.17.1.2: icmp_seq=1 ttl=64 time=0.095 ms

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