docker容器网络配置

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已于 2022-05-02 11:07:40 修改

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文章标签：网络 docker linux

于 2022-04-28 23:47:31 首次发布

本文链接：https://blog.youkuaiyun.com/qq_59324730/article/details/124480778

本文详细介绍了如何在Linux内核中创建和操作Network Namespace，重点讲解了使用ip netns命令，创建veth pair以实现在不同Network Namespace间的通信。接着探讨了Docker的四种网络模式配置，包括bridge、none、container和host模式，以及如何进行容器的网络配置，如主机名注入、DNS设置和端口映射。最后，展示了如何自定义docker0桥的网络属性及创建自定义网桥。

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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。（root不用）

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@localhost ~]# 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

默认情况下，Linux系统中是没有任何 Network Namespace的，所以ip netns list命令不会返回任何信息。

创建Network Namespace

通过命令创建一个名为ns0的命名空间：

[root@localhost ~]# ip netns add ns0
[root@localhost ~]# ip netns list
ns0

新创建的 Network Namespace 会出现在/var/run/netns/目录下。如果相同名字的 namespace 已经存在，命令会报Cannot create namespace file "/var/run/netns/ns0": File exists的错误。

[root@localhost ~]# ls /var/run/netns/
ns0
[root@localhost ~]# ip netns list
ns0
[root@localhost ~]# ip netns add ns0
Cannot create namespace file "/var/run/netns/ns0": File exists

对于每个 Network Namespace 来说，它会有自己独立的网卡、路由表、ARP 表、iptables 等和网络相关的资源。

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@localhost ~]# ip netns exec ns0 ip a      //状态是禁用
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@localhost ~]# ip netns exec ns0 ping 127.0.0.1    //ping自己ping不通，因为自己的状态是禁用的
connect: Network is unreachable

通过下面的命令启用lo回环网卡

[root@localhost ~]# ip netns exec ns0 ip link set lo up    //激活网卡
[root@localhost ~]# 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
[root@localhost ~]# 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=0.045 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.061 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.024 ms
^C
--- 127.0.0.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2050ms
rtt min/avg/max/mdev = 0.024/0.043/0.061/0.016 ms

[root@localhost ~]# ip netns exec ns1 ip link set lo up    //ns1和ns0现在之间不能通信
[root@localhost ~]# ip netns exec ns1 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
[root@localhost ~]# ip netns exec ns1 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=0.024 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.079 ms
^C
--- 127.0.0.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2034ms
rtt min/avg/max/mdev = 0.024/0.042/0.079/0.026 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@localhost ~]# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 00:0c:29:14:8b:cf brd ff:ff:ff:ff:ff:ff
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default 
    link/ether 02:42:3d:45:31:71 brd ff:ff:ff:ff:ff:ff
[root@localhost ~]# ip link add type veth
[root@localhost ~]# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 00:0c:29:14:8b:cf brd ff:ff:ff:ff:ff:ff
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default 
    link/ether 02:42:3d:45:31:71 brd ff:ff:ff:ff:ff:ff
6: veth0@veth1: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether de:0c:18:8a:48:2e brd ff:ff:ff:ff:ff:ff
7: veth1@veth0: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether 7e:e6:c2:28:39:82 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

下面我们利用veth pair实现两个不同的 Network Namespace 之间的通信。刚才我们已经创建了一个名为ns0的 Network Namespace，下面再创建一个信息Network Namespace，命名为ns1

[root@localhost ~]# ip netns list
ns1
ns0

然后我们将veth0加入到ns0，将veth1加入到ns1

[root@localhost ~]# ip link set veth0 netns ns0
[root@localhost ~]# ip link set veth1 netns ns1

然后我们分别为这对veth pair配置上ip地址，并启用它们

[root@localhost ~]# ip netns exec ns0 ip link set veth0 up
[root@localhost ~]# ip netns exec ns0 ip addr add 1.1.1.1/24 dev veth0
[root@localhost ~]# ip netns exec ns1 ip link set lo up
[root@localhost ~]# ip netns exec ns1 ip link set veth1 up
[root@localhost ~]# ip netns exec ns1 ip addr add 1.1.1.2/24 dev veth1

查看这对veth pair的状态

[root@localhost ~]# 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
6: veth0@if7: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether de:0c:18:8a:48:2e brd ff:ff:ff:ff:ff:ff link-netns ns1
    inet 1.1.1.1/24 scope global veth0
       valid_lft forever preferred_lft forever
    inet6 fe80::dc0c:18ff:fe8a:482e/64 scope link 
       valid_lft forever preferred_lft forever
[root@localhost ~]# ip netns exec ns1 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
7: veth1@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 7e:e6:c2:28:39:82 brd ff:ff:ff:ff:ff:ff link-netns ns0
    inet 1.1.1.2/24 scope global veth1
       valid_lft forever preferred_lft forever
    inet6 fe80::7ce6:c2ff:fe28:3982/64 scope link 
       valid_lft forever preferred_lft forever

从上面可以看出，我们已经成功启用了这个veth pair，并为每个veth设备分配了对应的ip地址。我们尝试在ns1中访问ns0中的ip地址：

[root@localhost ~]# ip netns exec ns1 ping 1.1.1.1
PING 1.1.1.1 (1.1.1.1) 56(84) bytes of data.
64 bytes from 1.1.1.1: icmp_seq=1 ttl=64 time=0.072 ms
64 bytes from 1.1.1.1: icmp_seq=2 ttl=64 time=0.082 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@localhost ~]# ip netns exec ns0 ip link set veth0 down
[root@localhost ~]# ip netns exec ns0 ip link set dev veth0 name eth0
[root@localhost ~]# ip netns exec ns0 ifconfig -a
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 1.1.1.1  netmask 255.255.255.0  broadcast 0.0.0.0
        inet6 fe80::30c4:23ff:fedd:a71c  prefixlen 64  scopeid 0x20<link>
        ether 32:c4:23:dd:a7:1c  txqueuelen 1000  (Ethernet)
        RX packets 12  bytes 928 (928.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 20  bytes 1576 (1.5 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
[root@localhost ~]# ip netns exec ns0 ip link set eth0 up

四种网络模式配置

bridge模式配置

[root@localhost ~]# docker run -it --name t1 --rm busybox /bin/sh
/ # 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
10: eth0@if11: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever
/ # ifconfig
eth0      Link encap:Ethernet  HWaddr 02:42:AC:11:00:02  
          inet addr:172.17.0.2  Bcast:172.17.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:27 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:3104 (3.0 KiB)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

/ # exit

[root@localhost ~]# docker container ls -a


# 在创建容器时添加--network bridge与不加--network选项效果是一致的
[root@localhost ~]# docker run -it --name t1 --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
10: eth0@if11: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever
/ # ifconfig
eth0      Link encap:Ethernet  HWaddr 02:42:AC:11:00:02  
          inet addr:172.17.0.2  Bcast:172.17.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:27 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:3104 (3.0 KiB)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

/ # exit

none模式配置(没有通信的网卡）

[root@localhost ~]# docker run -it --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
/ # ifconfig
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

/ # exit

container模式配置

启动第一个容器

[root@localhost ~]# docker run -it --rm --name b1 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
12: eth0@if13: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever
/ #

启动第二个容器

[root@localhost ~]# docker run -it --rm --name b2 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
/ #

可以看到名为b2的容器IP地址是172.17.0.3，与第一个容器的IP地址不是一样的，也就是说并没有共享网络，此时如果我们将第二个容器的启动方式改变一下，就可以使名为b2的容器IP与B1容器IP一致，也即共享IP，但不共享文件系统。

[root@localhost ~]# docker run -it --rm --network container:b1 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
12: eth0@if13: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:ac:11:00:02 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.2/16 brd 172.17.255.255 scope global eth0
       valid_lft forever preferred_lft forever
/ #

此时我们在b1容器上创建一个目录


/ # ls
bin   dev   etc   home  proc  root  sys   tmp   usr   var
/ # mkdir data
/ # ls
bin   data  dev   etc   home  proc  root  sys   tmp   usr   var
/ #

到b2容器上检查/tmp目录会发现并没有这个目录，因为文件系统是处于隔离状态，仅仅是共享了网络而已。

/ # ls
bin   dev   etc   home  proc  root  sys   tmp   usr   var

在b1容器上部署一个站点

/ # echo 'hello world' > data/index.html
/ # /bin/httpd -h /data
/ # netstat -antl
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       
tcp        0      0 :::80                   :::*                    LISTEN

在b2容器上用本地地址去访问此站点

/ # wget -o - -q 127.0.0.1:80
hello world

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

host模式配置

启动容器时直接指明模式为host

[root@localhost ~]# docker run -it --name b2 --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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel qlen 1000
    link/ether 00:0c:29:14:8b:cf brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.130/24 brd 192.168.31.255 scope global dynamic noprefixroute ens160
       valid_lft 1383sec preferred_lft 1383sec
    inet6 fe80::20c:29ff:fe14:8bcf/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:cf:17:64 brd ff:ff:ff:ff:ff:ff
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue 
    link/ether 02:42:3d:45:31:71 brd ff:ff:ff:ff:ff:ff
/ # ifconfig
docker0   Link encap:Ethernet  HWaddr 02:42:3D:45:31:71  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

ens160    Link encap:Ethernet  HWaddr 00:0C:29:14:8B:CF  
          inet addr:192.168.31.130  Bcast:192.168.31.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe14:8bcf/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1753 errors:0 dropped:0 overruns:0 frame:0
          TX packets:401 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:991831 (968.5 KiB)  TX bytes:44086 (43.0 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:184 errors:0 dropped:0 overruns:0 frame:0
          TX packets:184 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:15644 (15.2 KiB)  TX bytes:15644 (15.2 KiB)

virbr0    Link encap:Ethernet  HWaddr 52:54:00:CF:17:64  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

/ #

此时如果我们在这个容器中启动一个http站点，我们就可以直接用宿主机的IP直接在浏览器中访问这个容器中的站点了

容器的常用操作

查看容器的主机名

[root@localhost ~]# docker run -it --rm busybox
/ # hostname
cdb0f01d5bd9
/ #

在容器启动时注入主机名

[root@localhost ~]# docker run -it --rm --hostname node1 busybox
/ # hostname
node1
/ # cat /etc/hostname
node1
/ # 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
172.17.0.2	node1            # 注入主机名时会自动创建主机名到IP的映射关系
/ # mkdir /data
/ # echo 'hello world' > /data/index.html
/ # /bin/httpd -h /data/
/ # netstat -antl
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       
tcp        0      0 :::80                   :::*                    LISTEN      
/ # wget -o - -q node1
hello world

手动指定容器要使用的DNS

[root@localhost ~]# docker run -it --rm --hostname node1 --dns 8.8.8.8 busybox
/ # cat /etc/resolv.conf
search localdomain
nameserver 8.8.8.8
/ #

手动往/etc/hosts文件中注入主机名到IP地址的映射

//上面的操作
[root@localhost ~]# docker run -it --rm --hostname node1 --dns 8.8.8.8 busybox
/ # cat /etc/resolv.conf
search localdomain
nameserver 8.8.8.8  
//在第一个终端里
/ # mkdir /data
/ # echo 'hello world' > data/index.html
/ # /bin/httpd -f -h /data

//另起一个终端
[root@localhost ~]# docker run -it --rm --hostname node2 --add-host node1:172.17.0.2 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
172.17.0.2	node1
172.17.0.3	node2

开放容器端口

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 <containerPort>
- 将指定的容器端口映射至主机所有地址的一个动态端口
-p <hostPort>:<containerPort>
- 将容器端口<containerPort>映射至指定的主机端口<hostPort>
-p <ip>::<containerPort>
- 将指定的容器端口<containerPort>映射至主机指定<ip>的动态端口
-p <ip>:<hostPort>:<containerPort>
- 将指定的容器端口<containerPort>映射至主机指定<ip>的端口<hostPort>

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@localhost ~]# docker run --rm --name web -p 80 httpd
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
[Thu Apr 28 15:38:31.659963 2022] [mpm_event:notice] [pid 1:tid 139664551259456] AH00489: Apache/2.4.52 (Unix) configured -- resuming normal operations
[Thu Apr 28 15:38:31.660754 2022] [core:notice] [pid 1:tid 139664551259456] AH00094: Command line: 'httpd -D FOREGROUND'

以上命令执行后会一直占用着前端，我们新开一个终端连接来看一下容器的80端口被映射到了宿主机的什么端口上

[root@localhost ~]# docker port web
80/tcp -> 0.0.0.0:49154
80/tcp -> :::49154

由此可见，容器的80端口被暴露到了宿主机的49154端口上，此时我们在宿主机上访问一下这个端口看是否能访问到容器内的站点

[root@localhost ~]# curl http://127.0.0.1:49154
<!DOCTYPE html>
<html>
<head>
<title>Welcome to httpd!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to httpd!</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://httpd.org/">httpd.org</a>.<br/>
Commercial support is available at
<a href="http://httpd.com/">httpd.com</a>.</p>

<p><em>Thank you for using httpd.</em></p>
</body>
</html>

iptables防火墙规则将随容器的创建自动生成，随容器的删除自动删除规则。

将容器端口映射到指定IP的随机端口

[root@localhost ~]# docker run --name web --rm -p 192.168.31.130::80 httpd

在另一个终端上查看端口映射情况

[root@localhost ~]# docker port web
80/tcp -> 192.168.31.130:49154

将容器端口映射到宿主机的指定端口

[root@localhost ~]# docker run --name web --rm -p 80:80 httpd

在另一个终端上查看端口映射情况

[root@localhost ~]# docker port web
80/tcp -> 0.0.0.0:80

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在 /etc/docker/daemon.json配置文件 里修改

[root@localhost ~]# docker run -d --name web --restart=always httpd    //--restart=always，如果docker重启了，web跟着docker一起重启
34df94e1b46df41852463dca7f03f1601d90f64b9bd27691bcfa3d96b0ad1528

[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND              CREATED         STATUS         PORTS     NAMES
34df94e1b46d   httpd     "httpd-foreground"   4 seconds ago   Up 3 seconds   80/tcp    web

[root@localhost ~]# vim /etc/docker/daemon.json    //修改配置文件
{
  "registry-mirrors": ["https://6mi7k79l.mirror.aliyuncs.com"],  //只要不是最后一句都要加逗号
  "bip":"192.168.1.1/24"      //改ip地址
}

[root@localhost ~]# systemctl restart docker   //重启docker

[root@localhost ~]# 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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:14:8b:cf brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.130/24 brd 192.168.31.255 scope global dynamic noprefixroute ens160
       valid_lft 1610sec preferred_lft 1610sec
    inet6 fe80::20c:29ff:fe14:8bcf/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: virbr0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:3d:45:31:71 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.1/24 brd 192.168.1.255 scope global docker0    //修改成功
       valid_lft forever preferred_lft forever

[root@localhost ~]# docker inspect web
"Gateway": "192.168.1.1",
                    "IPAddress": "192.168.1.2",
                    "IPPrefixLen": 24,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:c0:a8:01:02",
                    "DriverOpts": null

核心选项为bip，用于指定docker桥自身的IP地址。如果是172开头的掩码是16位

docker创建自定义桥

创建一个br0网桥，不同于docker0

[root@localhost ~]# docker network create -d bridge --subnet "192.168.2.0/24" --gateway "192.168.2.1" br0     //创建网桥
2f7c0aa1fc11760f95eca28faa9449bc4a9c75077f73c6de405b7cb9a978667c
[root@localhost ~]# docker network ls     //查看
NETWORK ID     NAME      DRIVER    SCOPE
2f7c0aa1fc11   br0       bridge    local
3d16820de81c   bridge    bridge    local
a3cc3789f21e   host      host      local
ed48dbfced6a   none      null      local
[root@localhost ~]# 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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:14:8b:cf brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.130/24 brd 192.168.31.255 scope global dynamic noprefixroute ens160
       valid_lft 1034sec preferred_lft 1034sec
    inet6 fe80::20c:29ff:fe14:8bcf/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: virbr0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether 52:54:00:cf:17:64 brd ff:ff:ff:ff:ff:ff
5: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:3d:45:31:71 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.1/24 brd 192.168.1.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:3dff:fe45:3171/64 scope link 
       valid_lft forever preferred_lft forever
33: veth21185fb@if32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master docker0 state UP group default 
    link/ether 5e:8f:8e:a6:dd:2d brd ff:ff:ff:ff:ff:ff link-netnsid 2
    inet6 fe80::5c8f:8eff:fea6:dd2d/64 scope link 
       valid_lft forever preferred_lft forever
34: br-2f7c0aa1fc11: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:97:1e:22:53 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.1/24 brd 192.168.2.255 scope global br-2f7c0aa1fc11    //br0网桥
       valid_lft forever preferred_lft forever

用新创建的网桥br0 创建一个容器

[root@localhost ~]# docker run -it --rm --network br0 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
35: eth0@if36: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:02:02 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.2/24 brd 192.168.2.255 scope global eth0
       valid_lft forever preferred_lft forever
/ #

再用默认的网桥创建一个容器

[root@localhost ~]# docker run -it --rm --name b1 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
37: eth0@if38: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:01:02 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.2/24 brd 192.168.1.255 scope global eth0
       valid_lft forever preferred_lft forever
/ #

此时的b1和新网桥创建的容器能否互相通信，怎么通信（这种方式加入之后就是永久的，重启后还存在）

//另起第三个终端进行操作
[root@localhost ~]# docker network connect br0 b1   将b1连接上br0 网桥

//第二个终端b1容器上操作
/ # 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
37: eth0@if38: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:01:02 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.2/24 brd 192.168.1.255 scope global eth0
       valid_lft forever preferred_lft forever
39: eth1@if40: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:02:03 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.3/24 brd 192.168.2.255 scope global eth1    //连接上了
       valid_lft forever preferred_lft forever
/ # ping 192.168.2.2    //可以ping通
PING 192.168.2.2 (192.168.2.2): 56 data bytes
64 bytes from 192.168.2.2: seq=0 ttl=64 time=0.222 ms
64 bytes from 192.168.2.2: seq=1 ttl=64 time=0.070 ms
64 bytes from 192.168.2.2: seq=2 ttl=64 time=0.179 ms
64 bytes from 192.168.2.2: seq=3 ttl=64 time=0.187 ms
^C
--- 192.168.2.2 ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 0.070/0.164/0.222 ms


//在第一个终端上的 docker run -it --rm --network br0 busybox
操作
/ # 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
35: eth0@if36: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:02:02 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.2/24 brd 192.168.2.255 scope global eth0
/ # ping 192.168.2.3     //可以ping通同一个网段的，但是b1的另一个网段ping不通
PING 192.168.2.3 (192.168.2.3): 56 data bytes
64 bytes from 192.168.2.3: seq=0 ttl=64 time=0.077 ms
64 bytes from 192.168.2.3: seq=1 ttl=64 time=0.068 ms
64 bytes from 192.168.2.3: seq=2 ttl=64 time=0.069 ms
64 bytes from 192.168.2.3: seq=3 ttl=64 time=0.068 ms
^C
--- 192.168.2.3 ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 0.068/0.070/0.077 ms
/ # 



//第三个终端上
[root@localhost ~]# docker network disconnect br0 b1    //停止连接

//在b1上
/ # 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
37: eth0@if38: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:01:02 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.2/24 brd 192.168.1.255 scope global eth0
       valid_lft forever preferred_lft forever
/ #     //现在没了那个网段