命令

docker network connect 网络名称容器名称

参数

平时我们直接启动那个的命令是省略了默认参数–net bridge （即：使用我们的edocker0做路由）
So 使用自定义网络需要自己定义参数：

–driver bridge 网络模式
–subnet 192.168.0.0/16 IP地址/域 [192.168.0.2~192.168.255.255]
–gateway 192.168.0.1 默认网关

测试

# 新建自定义网络 mynet-02
root@db7d2aa74a7f:/# docker network create --driver bridge --subnet 193.168.0.0/16 --gateway 193.168.0.1 mynet-02
# 查看自定义网络 mynet-02 的信息
root@db7d2aa74a7f:/# docker network inspect mynet-02
[
    {
        "Name": "mynet-02",
        "Id": "05eefd1d85935337e304e73f073e8b03f6d288eab77307c267aed806922a1051",
        "Created": "2021-05-23T08:42:54.5906674Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": {},
            "Config": [
                {
                    "Subnet": "193.168.0.0/16",
                    "Gateway": "193.168.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {},
        "Options": {},
        "Labels": {}
    }
]

# 查看当前网络
root@db7d2aa74a7f:/# docker network ls
NETWORK ID          NAME                DRIVER              SCOPE
1ca1ad3cf619        bridge              bridge              local
8e5cc694b1a8        host                host                local
f532c792d595        mynet               bridge              local
05eefd1d8593        mynet-02            bridge              local
56951558f000        none                null                local

# 新建两个mynet-02网络下的tomcat容器
root@db7d2aa74a7f:/# docker run -d -P --name t-mynet02-01 tomcat
4090d6020e9eef9857a520d3aea110217e73b63aad49f2e4b57562e4c44c798f
root@db7d2aa74a7f:/# docker run -d -P --name t-mynet02-02 --net mynet-02 tomcat
9067df0f39fc1c3f81a8890d2b382440d8011521d1008e69dfd6eb2388037d29
# 查看正在运行中的容器
root@db7d2aa74a7f:/# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                     NAMES
0f9016021242        tomcat              "catalina.sh run"   24 seconds ago      Up 13 seconds       0.0.0.0:32781->8080/tcp   t-mynet02-01
9067df0f39fc        tomcat              "catalina.sh run"   56 seconds ago      Up 45 seconds       0.0.0.0:32780->8080/tcp   t-mynet02-02
509b121c9c33        tomcat              "catalina.sh run"   44 minutes ago      Up 44 minutes       0.0.0.0:32775->8080/tcp   tomcat-mynet-02
db49ff7883cc        tomcat              "catalina.sh run"   45 minutes ago      Up 45 minutes       0.0.0.0:32778->8080/tcp   tomcat-mynet-01

# ping
root@db7d2aa74a7f:/# docker exec -it t-mynet02-01 ping tomcat-mynet-01     # 不能
ping: tomcat-mynet-01: Temporary failure in name resolution

# 打通 tomcat-mynet-01 mynet-02
root@db7d2aa74a7f:/# docker network connect mynet-02 tomcat-mynet-01
root@db7d2aa74a7f:/# docker exec -it t-mynet02-01 ping tomcat-mynet-01     # tomcat-mynet-01 可以ping通 t-mynet02-01
PING tomcat-mynet-01 (193.168.0.4) 56(84) bytes of data.
64 bytes from tomcat-mynet-01.mynet-02 (193.168.0.4): icmp_seq=1 ttl=64 time=0.079 ms
64 bytes from tomcat-mynet-01.mynet-02 (193.168.0.4): icmp_seq=2 ttl=64 time=0.056 ms
^C
--- tomcat-mynet-01 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 35ms
rtt min/avg/max/mdev = 0.056/0.067/0.079/0.014 ms
root@db7d2aa74a7f:/# docker exec -it tomcat-mynet-01 ping t-mynet02-02     # tomcat-mynet-01 可以ping通 t-mynet02-02
PING t-mynet02-02 (193.168.0.2) 56(84) bytes of data.
64 bytes from t-mynet02-02.mynet-02 (193.168.0.2): icmp_seq=1 ttl=64 time=0.055 ms
64 bytes from t-mynet02-02.mynet-02 (193.168.0.2): icmp_seq=2 ttl=64 time=0.081 ms
^C
--- t-mynet02-02 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 22ms
rtt min/avg/max/mdev = 0.055/0.068/0.081/0.013 ms
root@db7d2aa74a7f:/# docker exec -it t-mynet02-01 ping tomcat-mynet-02     # t-mynet02-01 不能ping通 tomcat-mynet-02
ping: tomcat-mynet-02: Temporary failure in name resolution

# 打通 t-mynet02-01  mynet
root@db7d2aa74a7f:/# docker network connect mynet t-mynet02-01
root@db7d2aa74a7f:/# docker exec -it t-mynet02-01 ping tomcat-mynet-02     # t-mynet02-01 可以ping通 tomcat-mynet-02
PING tomcat-mynet-02 (192.168.0.3) 56(84) bytes of data.
64 bytes from tomcat-mynet-02.mynet (192.168.0.3): icmp_seq=1 ttl=64 time=0.076 ms
64 bytes from tomcat-mynet-02.mynet (192.168.0.3): icmp_seq=2 ttl=64 time=0.050 ms
^C
--- tomcat-mynet-02 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 36ms
rtt min/avg/max/mdev = 0.050/0.063/0.076/0.013 ms

BUT

t-mynet02-02 不能ping通 tomcat-mynet-02

root@db7d2aa74a7f:/# docker exec -it t-mynet02-02 ping tomcat-mynet-02     
ping: tomcat-mynet-02: Temporary failure in name resolution

原因

打通tomcat-mynet-01 mynet-02 后就是将tomcat-mynet-01放在了 mynet-02 网络下因此只要是在mynet-02网络下的都可以ping通 tomcat-mynet-01；
打通t-mynet02-01 mynet 后就是将t-mynet02-01放在了mynet网络下因此只要是在mynet网络下的都可以 ping 通t-mynet02-01而此时t-mynet02-02和tomcat-mynet-02并无关系因此仍旧无法ping通。