docker 容器网络配置

于 2021-01-07 20:57:32 发布
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1. Linux内核实现名称空间的创建

1.1 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@localhost ~]# ip netns help
Usage: ip netns list
       ip netns add NAME
       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

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。

1.2 创建Network Namespace

通过命令创建一个名为ns0的命名空间：

[root@localhost ~]# ip netns list
[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 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。

1.3 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 list
ns0
[root@localhost ~]# 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

//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
[root@localhost ~]# ip netns exec ns0 ip addr
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=0.121 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.037 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.065 ms
64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.062 ms
^C
--- 127.0.0.1 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 107ms
rtt min/avg/max/mdev = 0.037/0.071/0.121/0.031 ms
1.4 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。

1.5 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

//创建两个网卡
[root@localhost ~]# ip netns add ns0
[root@localhost ~]# ip netns add ns1
[root@localhost ~]# ip netns list
ns1
ns0
[root@localhost ~]# 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

//启动网卡
[root@localhost ~]# ip netns exec ns1 ip link set lo up
[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
1.6 创建veth pair
[root@localhost ~]# ip link add type veth
[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 mq state UP group default qlen 1000
    link/ether 00:0c:29:5c:c3:18 brd ff:ff:ff:ff:ff:ff
    inet 192.168.152.135/24 brd 192.168.152.255 scope global dynamic noprefixroute ens160
       valid_lft 1249sec preferred_lft 1249sec
    inet6 fe80::782d:ef05:5f3c:7024/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: veth0@veth1: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 0e:8f:39:91:0a:13 brd ff:ff:ff:ff:ff:ff
4: veth1@veth0: <BROADCAST,MULTICAST,M-DOWN> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 52:d4:c5:d0:ab:2c 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。

1.7 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。

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

//将veth0加入到ns0，将veth1加入到ns1
[root@localhost ~]# ip link set veth0 netns ns0
[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
3: veth0@if4: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 0e:8f:39:91:0a:13 brd ff:ff:ff:ff:ff:ff link-netnsid 0

[root@localhost ~]# ip link set veth1 netns ns1
[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
4: veth1@if3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 52:d4:c5:d0:ab:2c brd ff:ff:ff:ff:ff:ff link-netns ns0

//然后分别为这对veth pair配置上ip地址，并启用它们
[root@localhost ~]# ip netns exec ns0 ip addr add 192.168.152.1/24 dev veth0
[root@localhost ~]# ip netns exec ns0 ip link set veth0 up
[root@localhost ~]# ip netns exec ns0 ip add
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
3: veth0@if4: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state LOWERLAYERDOWN group default qlen 1000
    link/ether 0e:8f:39:91:0a:13 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.152.1/24 scope global veth0
       valid_lft forever preferred_lft forever

[root@localhost ~]# ip netns exec ns1 ip addr add 192.168.152.2/24 dev veth1
[root@localhost ~]# ip netns exec ns1 ip link set veth1 up
[root@localhost ~]# ip netns exec ns1 ip add
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
4: veth1@if3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 52:d4:c5:d0:ab:2c brd ff:ff:ff:ff:ff:ff link-netns ns0
    inet 192.168.152.2/24 scope global veth1
       valid_lft forever preferred_lft forever
    inet6 fe80::50d4:c5ff:fed0:ab2c/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 192.168.152.1
PING 192.168.152.1 (192.168.152.1) 56(84) bytes of data.
64 bytes from 192.168.152.1: icmp_seq=1 ttl=64 time=0.109 ms
64 bytes from 192.168.152.1: icmp_seq=2 ttl=64 time=0.100 ms

--- 192.168.152.1 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 110ms
rtt min/avg/max/mdev = 0.041/0.076/0.109/0.022 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。

1.8 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 ip link set eth0 up
[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
3: eth0@if4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 0e:8f:39:91:0a:13 brd ff:ff:ff:ff:ff:ff link-netns ns1
    inet 192.168.152.1/24 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::c8f:39ff:fe91:a13/64 scope link 
       valid_lft forever preferred_lft forever

[root@localhost ~]# ip netns exec ns1 ip link set veth1 down
[root@localhost ~]# ip netns exec ns1 ip link set dev veth1 name eth0
[root@localhost ~]# ip netns exec ns1 ip link set eth0 up
[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
4: eth0@if3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 52:d4:c5:d0:ab:2c brd ff:ff:ff:ff:ff:ff link-netns ns0
    inet 192.168.152.2/24 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::50d4:c5ff:fed0:ab2c/64 scope link 
       valid_lft forever preferred_lft forever

2. 四种网络模式配置

//根据对象来进行操作
[root@localhost ~]# docker container ls -a
CONTAINER ID   IMAGE     COMMAND              CREATED      STATUS                    PORTS     NAMES
c8dea7f29c09   httpd     "httpd-foreground"   2 days ago   Exited (255) 2 days ago   80/tcp    inspiring_kirch
[root@localhost ~]# docker container rm c8dea7f29c09
c8dea7f29c09
[root@localhost ~]# docker container ls -a
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
2.1 bridge模式配置
[root@localhost ~]# docker run -it --name lixian --rm busybox
/ # 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:9 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:766 (766.0 B)  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

//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 lixian --network bridge --rm busybox
/ # 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:9 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:766 (766.0 B)  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
2.2 none模式配置
  • 以下两种用法效果一致
[root@localhost ~]# docker run -it --rm --network=none busybox 
/ # 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
[root@localhost ~]# docker container run -it --rm --network=none busybox  
/ # 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
2.3 container模式配置
//启动第一个容器
[root@localhost ~]# docker container 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 container 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
/ # 

//在第一个容器上创建目录，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。
/ # mkdir /tmp/data
/ # ls /tmp
data

//在第二个容器上部署一个网页文件
/ # echo 'hello world' > /tmp/index.html
/ # ls /tmp
index.html
/ # httpd -h /tmp
/ # netstat -antl
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       
tcp        0      0 :::80                   :::*                    LISTEN      
//在第一个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
2.4 host模式配置

启动容器时直接指明模式为host

[root@localhost ~]# docker container run -it --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 mq qlen 1000
    link/ether 00:0c:29:5c:c3:18 brd ff:ff:ff:ff:ff:ff
    inet 192.168.152.135/24 brd 192.168.152.255 scope global dynamic noprefixroute ens160
       valid_lft 1378sec preferred_lft 1378sec
    inet6 fe80::782d:ef05:5f3c:7024/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue 
    link/ether 02:42:66:b5:f8:3d 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::42:66ff:feb5:f83d/64 scope link 
       valid_lft forever preferred_lft forever
/ # 

[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 mq state UP group default qlen 1000
    link/ether 00:0c:29:5c:c3:18 brd ff:ff:ff:ff:ff:ff
    inet 192.168.152.135/24 brd 192.168.152.255 scope global dynamic noprefixroute ens160
       valid_lft 1329sec preferred_lft 1329sec
    inet6 fe80::782d:ef05:5f3c:7024/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:66:b5:f8:3d 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::42:66ff:feb5:f83d/64 scope link 
       valid_lft forever preferred_lft forever
       
//在容器里创建一个网站文件
/ # ls /tmp/
/ # echo 'xiaozhan' > /tmp/index.html
/ # httpd -h /tmp
/ # netstat -antl
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      
tcp        0      0 192.168.152.135:22      192.168.152.1:56689     ESTABLISHED 
tcp        0      0 192.168.152.135:22      192.168.152.1:57988     ESTABLISHED 
tcp        0      0 :::80                   :::*                    LISTEN      
tcp        0      0 :::22                   :::*                    LISTEN      
//可以直接在真机上访问
[root@localhost ~]# curl http://127.17.0.1
xiaozhan

3. 容器的常用操作

3.1 查看容器的主机名
[root@localhost ~]# docker container run -it --rm busybox 
/ # hostname
a130d3541658    //容器ID和主机名一致
3.2 在容器启动时注入主机名
[root@localhost ~]# docker container run -it --rm --hostname=node2 busybox 
/ # hostname
node2
/ # 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	node2     //注入主机名时会自动创建主机名到IP的映射关系
/ # cat /etc/resolv.conf
# Generated by NetworkManager
search localdomain
nameserver 192.168.152.2    //DNS也会自动配置为宿主机的DNS
3.3 手动指定容器要使用的DNS
[root@localhost ~]# docker container run -it --rm --hostname=node2 --dns=114.114.114.114  busybox 
/ # cat /etc/resolv.conf 
search localdomain
nameserver 114.114.114.114
3.4 手动往/etc/hosts文件中注入主机名到IP地址的映射
[root@localhost ~]# docker container run -it --rm --hostname=node2 --dns=114.114.114.114 --add-host=www.a.com:1.1.1.1  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
1.1.1.1	www.a.com
172.17.0.2	node2
3.5 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
    • 将指定的容器端口映射至主机所有地址的一个动态端口
[root@localhost ~]# docker container run --rm -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 Jan 07 08:24:51.479687 2021] [mpm_event:notice] [pid 1:tid 140626646152320] AH00489: Apache/2.4.46 (Unix) configured -- resuming normal operations
[Thu Jan 07 08:24:51.490272 2021] [core:notice] [pid 1:tid 140626646152320] AH00094: Command line: 'httpd -D FOREGROUND'

[root@localhost ~]# docker ps
CONTAINER ID   IMAGE     COMMAND              CREATED          STATUS          PORTS                   NAMES
984f2a3646be   httpd     "httpd-foreground"   19 seconds ago   Up 17 seconds   0.0.0.0:49153->80/tcp   silly_cerf
[root@localhost ~]# ss -antl
State   Recv-Q   Send-Q      Local Address:Port      Peer Address:Port   
LISTEN  0        128               0.0.0.0:22             0.0.0.0:*      
LISTEN  0        128                  [::]:22                [::]:*      
LISTEN  0        128                     *:49153                *:*
  • -p :
    • 将容器端口映射至指定的主机端口
[root@localhost ~]# docker container run --rm -p 8080:80 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 Jan 07 08:26:46.679054 2021] [mpm_event:notice] [pid 1:tid 140419243721856] AH00489: Apache/2.4.46 (Unix) configured -- resuming normal operations
[Thu Jan 07 08:26:46.679616 2021] [core:notice] [pid 1:tid 140419243721856] AH00094: Command line: 'httpd -D FOREGROUND'

[root@localhost ~]# ss -antl
State   Recv-Q   Send-Q      Local Address:Port      Peer Address:Port   
LISTEN  0        128               0.0.0.0:22             0.0.0.0:*      
LISTEN  0        128                     *:8080                 *:*      
LISTEN  0        128                  [::]:22                [::]:*
  • -p ::
    • 将指定的容器端口映射至主机指定的动态端口
[root@localhost ~]# docker container run --rm -p 192.168.152.135::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 Jan 07 08:29:06.511886 2021] [mpm_event:notice] [pid 1:tid 140334767817856] AH00489: Apache/2.4.46 (Unix) configured -- resuming normal operations
[Thu Jan 07 08:29:06.512197 2021] [core:notice] [pid 1:tid 140334767817856] AH00094: Command line: 'httpd -D FOREGROUND'

[root@localhost ~]# ss -antl
State  Recv-Q   Send-Q        Local Address:Port      Peer Address:Port  
LISTEN 0        128                 0.0.0.0:22             0.0.0.0:*     
LISTEN 0        128         192.168.152.135:49153          0.0.0.0:*     
LISTEN 0        128                    [::]:22                [::]:*
  • -p ::
    • 将指定的容器端口映射至主机指定的端口
[root@localhost ~]# docker container run --rm -p 192.168.152.135:8080:80 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 Jan 07 08:30:40.139763 2021] [mpm_event:notice] [pid 1:tid 140219677901952] AH00489: Apache/2.4.46 (Unix) configured -- resuming normal operations
[Thu Jan 07 08:30:40.140202 2021] [core:notice] [pid 1:tid 140219677901952] AH00094: Command line: 'httpd -D FOREGROUND'

[root@localhost ~]# ss -antl
State   Recv-Q   Send-Q        Local Address:Port     Peer Address:Port  
LISTEN  0        128         192.168.152.135:8080          0.0.0.0:*     
LISTEN  0        128                 0.0.0.0:22            0.0.0.0:*     
LISTEN  0        128                    [::]:22               [::]:*

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 container run --rm -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 Jan 07 08:34:27.231356 2021] [mpm_event:notice] [pid 1:tid 140236784510080] AH00489: Apache/2.4.46 (Unix) configured -- resuming normal operations
[Thu Jan 07 08:34:27.231496 2021] [core:notice] [pid 1:tid 140236784510080] AH00094: Command line: 'httpd -D FOREGROUND'

[root@localhost ~]# ss -antl
State   Recv-Q   Send-Q      Local Address:Port      Peer Address:Port   
LISTEN  0        128               0.0.0.0:22             0.0.0.0:*      
LISTEN  0        128                  [::]:22                [::]:*      
LISTEN  0        128                     *:49154                *:*      

[root@localhost ~]# docker container ls
CONTAINER ID   IMAGE     COMMAND              CREATED              STATUS              PORTS                   NAMES
8b09bc54bb2d   httpd     "httpd-foreground"   About a minute ago   Up About a minute   0.0.0.0:49154->80/tcp   tender_elbakyan
[root@localhost ~]# docker container port 8b09bc54bb2d
80/tcp -> 0.0.0.0:49154      //容器的80端口被映射到了宿主机的随机端口上

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
<html><body><h1>It works!</h1></body></html>
3.6 自定义docker0桥的网络属性信息

官方文档相关配置

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

//修改配置文件
[root@localhost ~]# cd /etc/docker/
[root@localhost docker]# ls
daemon.json  key.json
[root@localhost docker]# vim daemon.json 

{
    "bip": "192.168.100.1/24",              //指定容器IP
    "dns": ["114.114.114.114","8.8.8.8"]，   //加上DNS
    "registry-mirrors": ["https://docker.mirrors.ustc.edu.cn/"]
}

//重新加载，重启
[root@localhost docker]# systemctl daemon-reload
[root@localhost docker]# systemctl restart docker
[root@localhost docker]# 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 mq state UP group default qlen 1000
    link/ether 00:0c:29:5c:c3:18 brd ff:ff:ff:ff:ff:ff
    inet 192.168.152.135/24 brd 192.168.152.255 scope global dynamic noprefixroute ens160
       valid_lft 1761sec preferred_lft 1761sec
    inet6 fe80::782d:ef05:5f3c:7024/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:66:b5:f8:3d brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.1/24 brd 192.168.100.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:66ff:feb5:f83d/64 scope link 
       valid_lft forever preferred_lft forever

//查看容器IP
[root@localhost ~]# docker container run --rm -it 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
32: eth0@if33: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:64:02 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.2/24 brd 192.168.100.255 scope global eth0
       valid_lft forever preferred_lft forever
       
[root@localhost ~]# docker container run --rm -it busybox
/ # cat /etc/resolv.conf 
search localdomain
nameserver 114.114.114.114
nameserver 8.8.8.8

核心选项为bip，即bridge ip之意，用于指定docker0桥自身的IP地址；其它选项可通过此地址计算得出。

3.7 docker远程连接

dockerd守护进程的C/S，其默认仅监听Unix Socket格式的地址(/var/run/docker.sock)，如果要使用TCP套接字，则需要修改/etc/docker/daemon.json配置文件，添加如下内容，然后重启docker服务：

[root@localhost docker]# vim daemon.json 
{
    "bip": "192.168.100.1/24",
    "hosts": ["tcp://0.0.0.0:2375","unix:///var/run/docker.sock"],  //加上此行
    "dns": ["114.114.114.114","8.8.8.8"]，
    "registry-mirrors": ["https://docker.mirrors.ustc.edu.cn/"]

//创建目录，编写配置文件
[root@localhost docker]# mkdir /etc/systemd/system/docker.service.d/
[root@localhost docker]# vim /etc/systemd/system/docker.service.d/docker.conf

[Service]
ExecStart=
ExecStart=/usr/bin/docker

[root@localhost docker]# systemctl daemon-reload
[root@localhost docker]# systemctl restart docker

在客户端上向dockerd直接传递“-H|–host”选项指定要控制哪台主机上的docker容器

[root@localhost ~]# docker -H 192.168.152.135:2375 container ls
CONTAINER ID   IMAGE     COMMAND       CREATED         STATUS         PORTS     NAMES
91d9d04e9231   centos    "/bin/bash"   6 seconds ago   Up 5 seconds             quizzical_moore
3.8 docker创建自定义桥
  • 创建一个额外的自定义桥，区别于docker0
[root@localhost ~]# docker network create -d bridge --subnet "192.168.222.0/24" --gateway "192.168.222.1" br0
afb766b964e6dfd6b09fa015d86541184fe125a9cb09f4b827c56ffd77d6c973
[root@localhost ~]# docker network ls
NETWORK ID     NAME      DRIVER    SCOPE
afb766b964e6   br0       bridge    local
315e0bc4661b   bridge    bridge    local
3768f35f721f   host      host      local
dbbc471751f4   none      null      local
  • 使用新创建的自定义桥来创建容器
[root@localhost ~]# docker run -it --name t1 --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
39: eth0@if40: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:de:02 brd ff:ff:ff:ff:ff:ff
    inet 192.168.222.2/24 brd 192.168.222.255 scope global eth0
       valid_lft forever preferred_lft forever
  • 再创建一个容器，使用默认的bridge桥
[root@localhost ~]# docker run -it --name t2 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
41: eth0@if42: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue 
    link/ether 02:42:c0:a8:64:02 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.2/24 brd 192.168.100.255 scope global eth0
       valid_lft forever preferred_lft forever
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