Docker 两个不同网络间实现连通

一、启动不同网络的容器

1、启动两个bridge（自带默认）桥接的容器

[root@yang ~]# docker run -it --name tomcat1 tomcat
[root@yang ~]# docker run -it --name tomcat2 tomcat

# 查看容器
[root@yang ~]# docker ps -a
CONTAINER ID        IMAGE                                 COMMAND                  CREATED             STATUS              PORTS                               NAMES
fcdd4c02da9c        tomcat                                "catalina.sh run"        2 days ago          Up 2 days           8080/tcp                            tomcat2
346962a1d73b        tomcat                                "catalina.sh run"        3 days ago          Up 2 days           8080/tcp                            tomcat1

2.启动两个mynet（自定义）桥接的容器

[root@yang ~]# docker run -it --name tomcat-net-01 --net mynet tomcat

[root@yang ~]# docker run -it --name tomcat-net-02 --net mynet tomcat

# 查看容器
[root@yang ~]# docker ps -a
CONTAINER ID        IMAGE                                 COMMAND                  CREATED             STATUS                     PORTS                               NAMES
8685e41a5962        tomcat                                "catalina.sh run"        2 days ago          Up 2 days                  8080/tcp                            tomcat-net-02
25e1b7c89af4        tomcat                                "catalina.sh run"        2 days ago          Up 2 days                  8080/tcp                            tomcat-net-01

二、目前两个容器连通性

示例图：

 

测试：

[root@yang ~]# docker exec -it tomcat01 ping tomcat-net-01
ping: tomcat-net-01: Temporary failure in name resolution

以上，明显提示ping不通，直接报错，因为这本来就是不可能连通的！

 三、两个不同网络，容器间互通

1.查看操作语法

[root@yang ~]# docker network connect --help

Usage:    docker network connect [OPTIONS] NETWORK CONTAINER

Connect a container to a network

Options:
      --alias strings           Add network-scoped alias for the container
      --driver-opt strings      driver options for the network
      --ip string               IPv4 address (e.g., 172.30.100.104)
      --ip6 string              IPv6 address (e.g., 2001:db8::33)
      --link list               Add link to another container
      --link-local-ip strings   Add a link-local address for the container

2.实际操作指令

[root@yang ~]# docker network connect mynet tomcat1

3.测试两者间是否互通

#  tomcat1 ping tomcat-net-01可以ping通！

[root@yang ~]# docker exec -it tomcat1 ping tomcat-net-01
PING tomcat-net-01 (192.168.0.2) 56(84) bytes of data.
64 bytes from tomcat-net-01.mynet (192.168.0.2): icmp_seq=1 ttl=64 time=0.209 ms
64 bytes from tomcat-net-01.mynet (192.168.0.2): icmp_seq=2 ttl=64 time=0.108 ms

#  tomcat1 ping tomcat-net-02 也可以ping通！

[root@yang ~]# docker exec -it tomcat1 ping tomcat-net-02
PING tomcat-net-02 (192.168.0.3) 56(84) bytes of data.
64 bytes from tomcat-net-02.mynet (192.168.0.3): icmp_seq=1 ttl=64 time=0.184 ms
64 bytes from tomcat-net-02.mynet (192.168.0.3): icmp_seq=2 ttl=64 time=0.275 ms

#  tomcat2 ping tomcat-net-02 ping不通（因为没有开通tomcat2到mynet网桥中）！

[root@yang ~]# docker exec -it tomcat2 ping tomcat-net-02
ping: tomcat-net-02: Temporary failure in name resolution

4.查看mynet内发生变化

[root@yang ~]# docker network inspect mynet
[
    {
        "Name": "mynet",
        "Id": "68bb4c7c3f1c6808ab2ce49a966e11440f560b89080b6a20f9c9b715d690519b",
        "Created": "2021-01-29T16:10:07.565642609+08:00",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": {},
            "Config": [
                {
                    "Subnet": "192.168.0.0/16",
                    "Gateway": "192.168.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "25e1b7c89af4744e9a7df48373886dc8f906c2e35dca2e644bf8deb81a6853db": {
                "Name": "tomcat-net-01",
                "EndpointID": "3e2a2d4e4807c4c7058f248720e653ffdb094238a6c34df403d501cf68fa559b",
                "MacAddress": "02:42:c0:a8:00:02",
                "IPv4Address": "192.168.0.2/16",
                "IPv6Address": ""
            },
            "346962a1d73badd263d10d76578ece0e6c2b33e1db08b264fb1fc66affd4a34a": {
                "Name": "tomcat1",
                "EndpointID": "d6eb17193d981338f7a1a178ace1751c9b8a6623a389072f71142deb41bddfb5",
                "MacAddress": "02:42:c0:a8:00:04",
                "IPv4Address": "192.168.0.4/16",
                "IPv6Address": ""
            },
            "8685e41a59628a81c69752f9785065f5985c2165ef9ee33edc5acec1d801fa51": {
                "Name": "tomcat-net-02",
                "EndpointID": "08e234cf42025805acc2bd7ae6a2dee602090e5f1f5e66ef5b7753e5654f348d",
                "MacAddress": "02:42:c0:a8:00:03",
                "IPv4Address": "192.168.0.3/16",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {}
    }
]

以上，显示mynet网桥中多出来一个tomcat1。

结论：

假如要跨网络操作别人，就需要用docker network connect 来实现连通！