docker network

docker network는 docker 컨테이너간 그리고 컨테이너 외부와의 통신 기능을 제공하는데 쓰입니다.

docker daemon을 실행하면 3개의 기본 network와 virtual network interface인 docker0가 생성됩니다.

$ docker network ls
NETWORK ID     NAME      DRIVER    SCOPE
1edf6f027a5a   bridge    bridge    local
3807b42fe5f2   host      host      local
e19d633c09eb   none      null      local

$ ifconfig
docker0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.17.0.1  netmask 255.255.0.0  broadcast 172.17.255.255
        inet6 fe80::ac5f:2bff:fe78:a8a4  prefixlen 64  scopeid 0x20<link>
        ether ae:5f:2b:78:a8:a4  txqueuelen 0  (Ethernet)
        RX packets 12  bytes 448 (448.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5  bytes 526 (526.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
(이하 생략)

컨테이너를 생성할 때 별다른 network 설정을 하지 않으면 이 중 bridge에 붙고,

기본적으로 생성된 bridge인 docker0의 subnet 172.17.0.0/16 에서 ip를 자동 할당받습니다.

$ docker network inspect bridge
[
    {
        "Name": "bridge",
        "Id": "1edf6f027a5a9191f0c22d5f65bf7943486bd7eea9bbf8f46cf79831ec85eea8",
        "Created": "2025-04-17T02:28:05.326458041+09:00",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv4": true,
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.17.0.0/16",
                    "Gateway": "172.17.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "160ca3dd1194017f88b679f8c158d07c25dc2a9db83cdbede7fbbf56ba2c3f75": {
                "Name": "apple",
                "EndpointID": "f4e94fd26a44962d82a87e74ef9f6046d614e8d2076eb79953a690260307bd50",
                "MacAddress": "46:81:c1:ae:92:a2",
                "IPv4Address": "172.17.0.2/16",
                "IPv6Address": ""
            },
            "f51c256e802528167da4f35275306333e5d7c801e6ef85b52c195b1a444f2c58": {
                "Name": "banana",
                "EndpointID": "7417a8619561da2203d8a31903d5982d941abe5f22b5f0a3410ebb750fcf91cb",
                "MacAddress": "6a:90:48:e1:e7:af",
                "IPv4Address": "172.17.0.3/16",
                "IPv6Address": ""
            }
        },
        "Options": {
            "com.docker.network.bridge.default_bridge": "true",
            "com.docker.network.bridge.enable_icc": "true",
            "com.docker.network.bridge.enable_ip_masquerade": "true",
            "com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
            "com.docker.network.bridge.name": "docker0",
            "com.docker.network.driver.mtu": "1500"
        },
        "Labels": {}
    }
]

위 예시에서 컨테이너 apple은 172.17.0.2, banana는 172.17.0.3를 할당받았습니다.

컨테이너간 통신 테스트차 apple에서 banana로 ping을 날리면