读取超时连接到 Docker 容器上的服务器

Question

我正在尝试连接到 DB/2 容器（图像：ibmcom/db2），但它给了我一个读取超时错误。主机操作系统是 Windows 10。我可以在 Windows PowerShell 提示符中看到端口 (50000)，但它给了我一个读取超时。

我添加了一个入站 Windows Defender 规则以允许所有本地端口和一个输出规则以允许所有远程端口。无论程序如何，我都有这个。我意识到这不是一个好习惯，但我试图排除防火墙问题。尽管如此，它仍然给我一个读取超时错误。我之前添加了更具体的规则，但它们自然没有帮助。

我还在该容器中启动了一个 SSH 服务器，并且可以从容器内部登录，但不能从容器外部登录。从外部连接时，我收到了相同的读取超时消息。我确实不觉得这是一个 db2 问题。

话虽如此，我还是可以让ickp/alpine-sshd:7.5-r2 和 gists/lighttpd 启动并可以从主机访问。也就是说，我可以看到 lighttpd 的 web 默认网页并登录到 alpine-sshd 的 SSHD 服务器。这两项工作都没有明显的延迟。这在进行上述防火墙调整之前有效。

我确信不知何故，这个容器不适合我。其他人已经尝试了我在下面提供的完全相同的 docker run，并且为他们提供了。

我使用的是 Win 10，WSL2。 Docker 版本 20.10.7，构建 f0df350。

我通过以下方式启动容器：

docker run -itd --name mydb-db2 \
                --privileged=true \
        -p 50000:50000 \
        -e LICENSE=accept \
        -e B2INSTANCE=db2inst1 \
        -e DB2INST1_PASSWORD=<mypassword> \
        -e DBNAME=MYDB \
        -e TO_CREATE_SAMPLEDB=false \
        -v db2:/database \
        ibmcom/db2 

Netstat 证据：

C:\Software>netstat /a /n |grep 50000
  TCP    0.0.0.0:50000          0.0.0.0:0              LISTENING
  TCP    [::]:50000             [::]:0                 LISTENING

尝试连接 jdbc:db2://localhost:50000/MYDB 在主机系统上导致“读取超时。ERRORCODE=-4499, SQLSTATE=08001”

Docker 容器状态：

~/projects-new/db2$ docker container ls
CONTAINER ID   IMAGE        COMMAND                  CREATED      STATUS          PORTS
                                              NAMES
110aa19976dd   ibmcom/db2   "/var/db2_setup/lib/…"   2 days ago   Up 28 minutes   22/tcp, 55000/tcp, 60006-60007/tcp, 0.0.0.0:50000->50000/tcp, :::50000->50000/tcp   mydb-db2

容器检查：

~/projects-new/db2$ docker container inspect 110aa
[
    {
        "Id": "110aa19976ddb53d16eac9376476f974fee8e9c699da3f76c1e2e13c444655c2",
        "Created": "2021-07-16T04:10:51.1247765Z",
        "Path": "/var/db2_setup/lib/setup_db2_instance.sh",
        "Args": [],
        "State": {
            "Status": "running",
            "Running": true,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            "Dead": false,
            "Pid": 5459,
            "ExitCode": 0,
            "Error": "",
            "StartedAt": "2021-07-18T03:56:45.0493495Z",
            "FinishedAt": "2021-07-18T03:54:18.4239523Z"
        },
        "Image": "sha256:a6a5ee354fb1242a75d508982041cd48883f3fe7c9c9b485be0da6c0ebd44a39",
        "ResolvConfPath": "/var/lib/docker/containers/110aa19976ddb53d16eac9376476f974fee8e9c699da3f76c1e2e13c444655c2/resolv.conf",
        "HostnamePath": "/var/lib/docker/containers/110aa19976ddb53d16eac9376476f974fee8e9c699da3f76c1e2e13c444655c2/hostname",
        "HostsPath": "/var/lib/docker/containers/110aa19976ddb53d16eac9376476f974fee8e9c699da3f76c1e2e13c444655c2/hosts",
        "LogPath": "/var/lib/docker/containers/110aa19976ddb53d16eac9376476f974fee8e9c699da3f76c1e2e13c444655c2/110aa19976ddb53d16eac9376476f974fee8e9c699da3f76c1e2e13c444655c2-json.log",
        "Name": "/mydb-db2",
        "RestartCount": 0,
        "Driver": "overlay2",
        "Platform": "linux",
        "MountLabel": "",
        "ProcessLabel": "",
        "AppArmorProfile": "",
        "ExecIDs": null,
        "HostConfig": {
            "Binds": [
                "db2:/database"
            ],
            "ContainerIDFile": "",
            "LogConfig": {
                "Type": "json-file",
                "Config": {}
            },
            "NetworkMode": "default",
            "PortBindings": {
                "50000/tcp": [
                    {
                        "HostIp": "",
                        "HostPort": "50000"
                    }
                ]
            },
            "RestartPolicy": {
                "Name": "no",
                "MaximumRetryCount": 0
            },
            "AutoRemove": false,
            "VolumeDriver": "",
            "VolumesFrom": null,
            "CapAdd": null,
            "CapDrop": null,
            "CgroupnsMode": "host",
            "Dns": [],
            "DnsOptions": [],
            "DnsSearch": [],
            "ExtraHosts": null,
            "GroupAdd": null,
            "IpcMode": "private",
            "Cgroup": "",
            "Links": null,
            "OomScoreAdj": 0,
            "PidMode": "",
            "Privileged": true,
            "PublishAllPorts": false,
            "ReadonlyRootfs": false,
            "SecurityOpt": [
                "label=disable"
            ],
            "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": null,
            "ReadonlyPaths": null
        },
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/b6ecb6d5e949ab8e58d9238e34878a563a45f5045d57c684e5a08b6ec833ebb4-init/diff:/var/lib/docker/overlay2/6cf25bf1ac29315c3832316ef32b1cae8cf1ed6e71e4ddd9d08ab5566f81da9e/diff:/var/lib/docker/overlay2/76ca13571a6d253356b48ac20b408d33f80c5e6b429c132533e60c7578e99fb3/diff:/var/lib/docker/overlay2/e1a78196ef6f70929701e708904cb2696189c37a40839a0f20407148d2d90f1d/diff:/var/lib/docker/overlay2/efa2b4a3bc7e7411a671f05ad9121a4bb609452560b5f73d4b765e8519bfa36d/diff:/var/lib/docker/overlay2/933425814e17216adcfcac390e789c6dfc8ada12ded902db2ca9a542a5ff555c/diff:/var/lib/docker/overlay2/2ec2f25d859b77fd93a16468e40de569c41b35055c58277ad97d839cb33a01ac/diff:/var/lib/docker/overlay2/62aeaecc9fea67541671d95f691a2d8ddc9076ee0ae3bc96cd3b030a3ecc663b/diff:/var/lib/docker/overlay2/f04ce4e91dedc0c14073e43734ca252a7c0bd6f6ed9ab89f77d6797f72312f2d/diff:/var/lib/docker/overlay2/21b929e594040a64ffb0cd2c8bd4d3d7f630a3ec3dd79e8157c41c0d9783faa6/diff:/var/lib/docker/overlay2/c5e235fc2e9dc254394bcae472264b133530f5dfbb285cfe5f0ba0dac26ce4c4/diff:/var/lib/docker/overlay2/8f68a8bb1e9ca565aa1d8debc221bb498512a6ed24cc07bcf3ef07c8c42e045f/diff:/var/lib/docker/overlay2/745a0aa01d1a904ce08c22d07be527cdb39da0c37b87a66a57062cc307ca4d4c/diff:/var/lib/docker/overlay2/f0a873fda45d17a036833dd0dc9362f02b0ab00c590f23bf38ba59d06c624272/diff",
                "MergedDir": "/var/lib/docker/overlay2/b6ecb6d5e949ab8e58d9238e34878a563a45f5045d57c684e5a08b6ec833ebb4/merged",
                "UpperDir": "/var/lib/docker/overlay2/b6ecb6d5e949ab8e58d9238e34878a563a45f5045d57c684e5a08b6ec833ebb4/diff",
                "WorkDir": "/var/lib/docker/overlay2/b6ecb6d5e949ab8e58d9238e34878a563a45f5045d57c684e5a08b6ec833ebb4/work"
            },
            "Name": "overlay2"
        },
        "Mounts": [
            {
                "Type": "volume",
                "Name": "db2",
                "Source": "/var/lib/docker/volumes/db2/_data",
                "Destination": "/database",
                "Driver": "local",
                "Mode": "z",
                "RW": true,
                "Propagation": ""
            },
            {
                "Type": "volume",
                "Name": "47c06e44c75f70947a907a0972924536761f70f15971459e8be6015b29e2e48c",
                "Source": "/var/lib/docker/volumes/47c06e44c75f70947a907a0972924536761f70f15971459e8be6015b29e2e48c/_data",
                "Destination": "/hadr",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }
        ],
        "Config": {
            "Hostname": "110aa19976dd",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "22/tcp": {},
                "50000/tcp": {},
                "55000/tcp": {},
                "60006/tcp": {},
                "60007/tcp": {}
            },
            "Tty": true,
            "OpenStdin": true,
            "StdinOnce": false,
            "Env": [
                "LICENSE=accept",
                "B2INSTANCE=db2inst1",
                "DB2INST1_PASSWORD=<mypassword>",
                "DBNAME=BLUECOST",
                "TO_CREATE_SAMPLEDB=false",
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "container=oci",
                "STORAGE_DIR=/database",
                "HADR_SHARED_DIR=/hadr",
                "DBPORT=50000",
                "TSPORT=55000",
                "SETUPDIR=/var/db2_setup",
                "SETUPAREA=/tmp/setup",
                "NOTVISIBLE=in users profile",
                "LICENSE_NAME=db2dec.lic"
            ],
            "Cmd": null,
            "Image": "ibmcom/db2",
            "Volumes": {
                "/database": {},
                "/hadr": {}
            },
            "WorkingDir": "",
            "Entrypoint": [
                "/var/db2_setup/lib/setup_db2_instance.sh"
            ],
            "OnBuild": null,
            "Labels": {
                "architecture": "x86_64",
                "build-date": "2021-06-01T05:31:45.840349",
                "com.redhat.build-host": "cpt-1007.osbs.prod.upshift.rdu2.redhat.com",
                "com.redhat.component": "ubi7-container",
                "com.redhat.license_terms": "https://www.redhat.com/en/about/red-hat-end-user-license-agreements#UBI",
                "description": "The Universal Base Image is designed and engineered to be the base layer for all of your containerized applications, middleware and utilities. This base image is freely redistributable, but Red Hat only supports Red Hat technologies through subscriptions for Red Hat products. This image is maintained by Red Hat and updated regularly.",
                "desktop.docker.io/wsl-distro": "Ubuntu-20.04",
                "distribution-scope": "public",
                "io.k8s.description": "The Universal Base Image is designed and engineered to be the base layer for all of your containerized applications, middleware and utilities. This base image is freely redistributable, but Red Hat only supports Red Hat technologies through subscriptions for Red Hat products. This image is maintained by Red Hat and updated regularly.",
                "io.k8s.display-name": "Red Hat Universal Base Image 7",
                "io.openshift.tags": "base rhel7",
                "name": "ubi7",
                "release": "405",
                "summary": "Provides the latest release of the Red Hat Universal Base Image 7.",
                "url": "https://access.redhat.com/containers/#/registry.access.redhat.com/ubi7/images/7.9-405",
                "vcs-ref": "a4e710a688a6374670ecdd56637c3f683d11cbe3",
                "vcs-type": "git",
                "vendor": "Red Hat, Inc.",
                "version": "7.9"
            }
        },
        "NetworkSettings": {
            "Bridge": "",
            "SandboxID": "570856178f99951c7cdfccc638a3404f906a7a89905ba9d39181cd9310f4380b",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {
                "22/tcp": null,
                "50000/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "50000"
                    },
                    {
                        "HostIp": "::",
                        "HostPort": "50000"
                    }
                ],
                "55000/tcp": null,
                "60006/tcp": null,
                "60007/tcp": null
            },
            "SandboxKey": "/var/run/docker/netns/570856178f99",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "a50d8643af88c0d677a9dc2d889f20ab909f46707bb7bd0f8168666b18d1b414",
            "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": "408fe3a7130f9791810b8668b60b7f90478f4673f79270539044362e8c12d88f",
                    "EndpointID": "a50d8643af88c0d677a9dc2d889f20ab909f46707bb7bd0f8168666b18d1b414",
                    "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
                }
            }
        }
    }
]

我没有看到列出的 db2 容器。这些是我的网络：

C:\Software>docker network ls
NETWORK ID     NAME                             DRIVER    SCOPE
408fe3a7130f   bridge                           bridge    local
38fc17e8e6f1   cirrus-ssc-file-sender_default   bridge    local
1668ab71959f   host                             host      local
4bf4f6b3a57e   minikube                         bridge    local
e07fc0032414   none                             null      local

相反，我是在桥接网络上找到的。

我不想做任何花哨的事情。我真的宁愿它在同一个网络主机上运行。如果主机系统可以通过Netstat“看到”暴露的50000端口，那不是防火墙问题吗？

更新：我关闭了 Windows Defender，但它仍然无法正常工作。

更新 2：我在不同的机器上托管了相同的容器，但在我的家庭网络上。当我尝试从问题机器连接到它时，它给了我相同的读取超时错误。但是，它在主机上工作。不知何故，这台特定的 Windows 机器和这个特定的容器之间似乎存在问题。

更新 3：SVCENAME 信息： 我在 db2 容器中运行了以下内容：

$su db2inst1 (when I log in it goes to root)
$cd ~
$. ./.bashrc
$db2 get dbm cfg |grep SVCENAME
TCP/IP Service name                          (SVCENAME) = db2c_db2inst1
 SSL service name                         (SSL_SVCENAME) =
$grep dbc2_db2inst1 /etc/services
db2c_db2inst1      50000/tcp
db2c_db2inst1_ssl  50001/tcp

DB2 容器操作系统版本信息：

$ cat /etc/*release
NAME="Red Hat Enterprise Linux Server"
VERSION="7.9 (Maipo)"
ID="rhel"
ID_LIKE="fedora"
VARIANT="Server"
VARIANT_ID="server"
VERSION_ID="7.9"
PRETTY_NAME="Red Hat Enterprise Linux Server 7.9 (Maipo)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:redhat:enterprise_linux:7.9:GA:server"
HOME_URL="https://www.redhat.com/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"

REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 7"
REDHAT_BUGZILLA_PRODUCT_VERSION=7.9
REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
REDHAT_SUPPORT_PRODUCT_VERSION="7.9"
Red Hat Enterprise Linux Server release 7.9 (Maipo)
Red Hat Enterprise Linux Server release 7.9 (Maipo)

使用的 WSL Linux 版本：

$ cat /etc/*release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.1 LTS"
NAME="Ubuntu"
VERSION="20.04.1 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.1 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal

主机系统的Windows版本信息（来自winver）： 视窗 10 版本 21H1（操作系统内部版本 19043.1110）

计算机成功连接到 DB/2 容器：

$ cat /etc/*release
Fedora release 30 (Thirty)
NAME=Fedora
VERSION="30 (Workstation Edition)"
ID=fedora
VERSION_ID=30
VERSION_CODENAME=""
PLATFORM_ID="platform:f30"
PRETTY_NAME="Fedora 30 (Workstation Edition)"
ANSI_COLOR="0;34"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:30"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f30/system-administrators-guide/"
SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=30
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=30
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
VARIANT="Workstation Edition"
VARIANT_ID=workstation
Fedora release 30 (Thirty)
Fedora release 30 (Thirty)

Answer 1

您的症状可能是由某些特定于机器的配置或某些低级组件（尤其是 WSL2）引起的。

在我的硬件上，在当前日期，使用当前版本的 WSL2，ibmcom/db2 接受来自本地 MS-Windows 主机（通过 jdbc）的连接，其中包含以下组件组合：

• MS-Windows 10 Pro build 19043 (21H1) x64
• “用于 x64 机器的 Linux WSL2 内核包”的最新版本
• Docker Desktop 3.5.2 配置为使用 WSL2

但是，通过以前的配置组合，我使用 WSL2 重新创建了您的故障症状，即从本地 MSWindows 主机到 linux 容器的 jdbc 连接尝试给出了 sqlcode -4499（在我的情况下，reply.fill() 数据不足）。

失败的组合是：

• MS-Windows 10 Pro build 19041 x64。
• “用于 x64 机器的 Linux WSL2 内核包”的旧版本（在 2021 年 7 月 22 日之前下载）
• 为 WSL2 配置的 Docker Desktop 3.5.2

使用之前失败的组合，只有 WSL2 后端重新创建了您的症状，但 Hyper-V 后端工作正常。

在 Win10PRO 环境中使用 Docker-Desktop，右键单击其图标，选择设置，然后您可以勾选（或取消勾选）“使用基于 WSL2 的引擎”，单击应用并重新启动。您可能会收到其他通知。您可能会丢失容器和图像，需要重新下载它们，因此如果您需要保留任何数据，请在更改后端之前单独安排。

如果您无法通过升级组件取得进展，则可以选择重新安装或映像。

Answer 2

容器看不到下层存在的文件的只读副本。

复制让容器更高效

当您启动容器时，会在其他层之上添加一个薄的可写容器层。容器对文件系统所做的任何更改都存储在这里。容器未更改的任何文件都不会复制到此可写层。这意味着可写层尽可能小。

当修改容器中的现有文件时，存储驱动程序会执行写时复制操作。涉及的具体步骤取决于特定的存储驱动程序。对于 aufs、overlay 和 overlay2 驱动程序，写时复制操作遵循以下粗略顺序：

• 在图像层中搜索要更新的文件。过程 从最新的层开始，向下一层到基础层 一次。找到结果后，将它们添加到缓存中以加快速度 未来的操作。

• 对文件的第一个副本执行 copy_up 操作 找到，将文件复制到容器的可写层。

• 对该文件的此副本进行任何修改，并且 容器看不到文件中存在的只读副本 下层。

Btrfs、ZFS 和其他驱动程序以不同方式处理写时复制。您可以稍后在详细说明中阅读有关这些驱动程序的方法的更多信息。

写入大量数据的容器比不写入的容器消耗更多空间。这是因为大多数写操作在容器的薄可写顶层中消耗了新空间。

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