docker - 可以通过桥 IP 连接到 docker 容器，但不能通过 pod 容器内的 0.0.0.0 连接

Question

我正在运行 Jenkins，它在运行 maven 构建的 pod 中运行容器。
在构建中，测试启动了 mysql 容器并获得“连接被拒绝”。在本地，在 Jenkins 之外，它运行良好。
容器通过以下方式运行:

docker run --name mysql_unit_test -e MYSQL_ROOT_PASSWORD=abcd1234! -e MYSQL_DATABASE=db -p 4306:3306 -d mysql:5.7.13

docker ps产生:

816a19116f2d  mysql:5.7.13  "docker-entrypoint.s…"  17 hours ago  Up 17 hours  0.0.0.0:4306->3306/tcp  mysql_unit_test

和 docker inspect :

[
    {
        "Id": "816a19116f2dd947013baa2abe5555317afec448fa8f56258fce4dce53f33a09",
        "Created": "2020-07-22T04:43:36.556743179Z",
        "Path": "docker-entrypoint.sh",
        "Args": [
            "mysqld"
        ],
        "State": {
            "Status": "running",
            "Running": true,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            "Dead": false,
            "Pid": 84461,
            "ExitCode": 0,
            "Error": "",
            "StartedAt": "2020-07-22T04:43:37.219671572Z",
            "FinishedAt": "0001-01-01T00:00:00Z"
        },
        "Image": "sha256:1195b21c3a45d9bf93aae497f2538f89a09aaded18d6648753aa3ce76670f41d",
        "ResolvConfPath": "/var/lib/docker/containers/816a19116f2dd947013baa2abe5555317afec448fa8f56258fce4dce53f33a09/resolv.conf",
        "HostnamePath": "/var/lib/docker/containers/816a19116f2dd947013baa2abe5555317afec448fa8f56258fce4dce53f33a09/hostname",
        "HostsPath": "/var/lib/docker/containers/816a19116f2dd947013baa2abe5555317afec448fa8f56258fce4dce53f33a09/hosts",
        "LogPath": "/var/lib/docker/containers/816a19116f2dd947013baa2abe5555317afec448fa8f56258fce4dce53f33a09/816a19116f2dd947013baa2abe5555317afec448fa8f56258fce4dce53f33a09-json.log",
        "Name": "/mysql_unit_test",
        "RestartCount": 0,
        "Driver": "overlay2",
        "Platform": "linux",
        "MountLabel": "",
        "ProcessLabel": "",
        "AppArmorProfile": "docker-default",
        "ExecIDs": null,
        "HostConfig": {
            "Binds": null,
            "ContainerIDFile": "",
            "LogConfig": {
                "Type": "json-file",
                "Config": {
                    "max-file": "5",
                    "max-size": "50m"
                }
            },
            "NetworkMode": "default",
            "PortBindings": {
                "3306/tcp": [
                    {
                        "HostIp": "",
                        "HostPort": "4306"
                    }
                ]
            },
            "RestartPolicy": {
                "Name": "no",
                "MaximumRetryCount": 0
            },
            "AutoRemove": false,
            "VolumeDriver": "",
            "VolumesFrom": null,
            "CapAdd": null,
            "CapDrop": null,
            "Capabilities": null,
            "Dns": [],
            "DnsOptions": [],
            "DnsSearch": [],
            "ExtraHosts": null,
            "GroupAdd": null,
            "IpcMode": "private",
            "Cgroup": "",
            "Links": null,
            "OomScoreAdj": 0,
            "PidMode": "",
            "Privileged": false,
            "PublishAllPorts": false,
            "ReadonlyRootfs": false,
            "SecurityOpt": null,
            "UTSMode": "",
            "UsernsMode": "",
            "ShmSize": 67108864,
            "Runtime": "runc",
            "ConsoleSize": [
                0,
                0
            ],
            "Isolation": "",
            "CpuShares": 0,
            "Memory": 0,
            "NanoCpus": 0,
            "CgroupParent": "",
            "BlkioWeight": 0,
            "BlkioWeightDevice": [],
            "BlkioDeviceReadBps": null,
            "BlkioDeviceWriteBps": null,
            "BlkioDeviceReadIOps": null,
            "BlkioDeviceWriteIOps": null,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "Devices": [],
            "DeviceCgroupRules": null,
            "DeviceRequests": null,
            "KernelMemory": 0,
            "KernelMemoryTCP": 0,
            "MemoryReservation": 0,
            "MemorySwap": 0,
            "MemorySwappiness": null,
            "OomKillDisable": false,
            "PidsLimit": null,
            "Ulimits": null,
            "CpuCount": 0,
            "CpuPercent": 0,
            "IOMaximumIOps": 0,
            "IOMaximumBandwidth": 0,
            "MaskedPaths": [
                "/proc/asound",
                "/proc/acpi",
                "/proc/kcore",
                "/proc/keys",
                "/proc/latency_stats",
                "/proc/timer_list",
                "/proc/timer_stats",
                "/proc/sched_debug",
                "/proc/scsi",
                "/sys/firmware"
            ],
            "ReadonlyPaths": [
                "/proc/bus",
                "/proc/fs",
                "/proc/irq",
                "/proc/sys",
                "/proc/sysrq-trigger"
            ]
        },
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/ccba4cc84fd186833c2bb0a6976a356bf1167cc834b06f4165984367b8ca69ef-init/diff:/var/lib/docker/overlay2/cf95f3dcd155ff4d3723bb3283e50af755a9a48c1febef3b1889ace131b9242d/diff:/var/lib/docker/overlay2/58a035059ace166a43c538e8bd48d80ad80af4bf5c43a3ff1da6b31490fd6380/diff:/var/lib/docker/overlay2/045b842ce5119b1ec1aa1da2e93a54d69df9d16cdbc531746089a4e881bff44a/diff:/var/lib/docker/overlay2/ed9de3c8ec5891ee8619e4cca70ea041b112650b3fce543840e25ce5acf038f7/diff:/var/lib/docker/overlay2/cf3af22c1d68cd4b42f97896d5b55f9433972354f67b48499fce6fd7a9c8b2da/diff:/var/lib/docker/overlay2/079d799ee0d806d8428533c7ca65347bc579d795e47b5fb8d9f0491d11658261/diff:/var/lib/docker/overlay2/ba3cd6723b68d9cde09712cad0dd6f6a3cd3989e5f69872a35d60ea5ab76a12d/diff:/var/lib/docker/overlay2/0c9c8a78c4f329888e1fb40aba0fc688f1090c84a6823aa443d08445f2c9ba5f/diff:/var/lib/docker/overlay2/12cac8cdd33fabd38487d14a1599516f14bd79421f5a9a04cf926ca8d2c5bc0f/diff:/var/lib/docker/overlay2/f844165a3a8f81c0d5703f0e27b6cb3ace6c6559b256f1b4dcf91158e0f5a384/diff:/var/lib/docker/overlay2/34c41e90c5210a0aec026543d85d5c17e01287a087607b79c74db82ebff94ee5/diff",
                "MergedDir": "/var/lib/docker/overlay2/ccba4cc84fd186833c2bb0a6976a356bf1167cc834b06f4165984367b8ca69ef/merged",
                "UpperDir": "/var/lib/docker/overlay2/ccba4cc84fd186833c2bb0a6976a356bf1167cc834b06f4165984367b8ca69ef/diff",
                "WorkDir": "/var/lib/docker/overlay2/ccba4cc84fd186833c2bb0a6976a356bf1167cc834b06f4165984367b8ca69ef/work"
            },
            "Name": "overlay2"
        },
        "Mounts": [
            {
                "Type": "volume",
                "Name": "571074f25fbd2d154dcf2b563af0a3fd42c1d5987c561f4fb23ba37c785a49d1",
                "Source": "/var/lib/docker/volumes/571074f25fbd2d154dcf2b563af0a3fd42c1d5987c561f4fb23ba37c785a49d1/_data",
                "Destination": "/var/lib/mysql",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }
        ],
        "Config": {
            "Hostname": "816a19116f2d",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "3306/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "MYSQL_ROOT_PASSWORD=abcd1234!",
                "MYSQL_DATABASE=db",
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "GOSU_VERSION=1.7",
                "MYSQL_MAJOR=5.7",
                "MYSQL_VERSION=5.7.13-1debian8"
            ],
            "Cmd": [
                "mysqld"
            ],
            "Image": "mysql:5.7.13",
            "Volumes": {
                "/var/lib/mysql": {}
            },
            "WorkingDir": "",
            "Entrypoint": [
                "docker-entrypoint.sh"
            ],
            "OnBuild": null,
            "Labels": {}
        },
        "NetworkSettings": {
            "Bridge": "",
            "SandboxID": "99fb1d64dbd98500d7dddae88ea2b53e712da9a709f8541fcae413f52d18a309",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {
                "3306/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "4306"
                    }
                ]
            },
            "SandboxKey": "/var/run/docker/netns/99fb1d64dbd9",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "375f5604e67cd5282d09585e2b211df7d8c1482b448f95003b38eaf5755c3982",
            "Gateway": "172.17.0.1",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "172.17.0.2",
            "IPPrefixLen": 16,
            "IPv6Gateway": "",
            "MacAddress": "02:42:ac:11:00:02",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "526388f448225716c3159ae806600b8507086e898f41d3945d24d8c4572e3848",
                    "EndpointID": "375f5604e67cd5282d09585e2b211df7d8c1482b448f95003b38eaf5755c3982",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]

和 telnet :

telnet 0.0.0.0 4306
Trying 0.0.0.0...
telnet: Unable to connect to remote host: Connection refused

telnet 172.17.0.1 4306
Trying 172.17.0.1...
Connected to 172.17.0.1.

默认情况下，测试使用 jdbc:mysql://0.0.0.0:4306/db ，但是如果我将其更改为 jdbc:mysql://172.17.0.1:4306/db它能够连接。
我尝试使用 postgres而不是 mysql并有同样的问题。
我的问题是为什么它无法连接到 0.0.0.0 ?是因为它是容器中容器中的容器吗？我是这项技术的新手。

Answer 1

0.0.0.0甚至不是 address 🤷，所以我不希望它起作用。它通常用于服务器/服务以绑定(bind)到 any IP 地址(或含义不适用)但不是由尝试连接到服务器/服务的客户端。如果您真的在本地连接，您可以使用 localhost (DNS 规范)或只是 127.0.0.1 .您没有在测试中指定连接字符串，但它可能只是连接到本地套接字 /var/lib/mysql/mysql.sock而不是 IP 地址 (❓)172.17.0.1是本地容器地址，因此只要您公开端口，它就始终可以工作，但问题是您的容器可能并不总是具有相同的地址，具体取决于您实例化容器的特定机器上运行的内容。
✌️