docker 的网络命令空间

在 docker 创建后，通过 docker inspect 命令，可以获取 docker 网络命令空间的描述符路径：

[root@vac_master0 ~]# docker ps -a
CONTAINER ID        IMAGE                                           COMMAND                  CREATED             STATUS              PORTS               NAMES
697950c08c2e        192.168.84.83:5000/x86_64/mpu/utelnetd:latest   "/usr/sbin/myUtelnetd"   6 days ago          Up 6 days                               tpa_vac
14326fe79a36        registry:2.6.2                                  "/entrypoint.sh /e..."   2 weeks ago         Up 6 days                               lpm_registry
[root@vac_master0 ~]#
[root@vac_master0 ~]# docker inspect tpa_vac
[
    {
        "Id": "697950c08c2e11425b1e1ea6ddc4e60fbff929e0746bb65ef328d0f6e08d2263",
        "Created": "2021-02-02T03:52:29.709566861Z",
        "Path": "/usr/sbin/myUtelnetd",
        "Args": [],
        "State": {
            "Status": "running",
            "Running": true,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            "Dead": false,
            "Pid": 4940,
            "ExitCode": 0,
            "Error": "",
            "StartedAt": "2021-02-02T03:52:31.00728144Z",
            "FinishedAt": "0001-01-01T00:00:00Z"
        },
        "Image": "sha256:97fffa246d3c50f6e64f99654012616826252ecefd39859bdeca0c08e6fa3e53",
        "ResolvConfPath": "/var/lib/docker/containers/697950c08c2e11425b1e1ea6ddc4e60fbff929e0746bb65ef328d0f6e08d2263/resolv.conf",
        "HostnamePath": "/var/lib/docker/containers/697950c08c2e11425b1e1ea6ddc4e60fbff929e0746bb65ef328d0f6e08d2263/hostname",
        "HostsPath": "/var/lib/docker/containers/697950c08c2e11425b1e1ea6ddc4e60fbff929e0746bb65ef328d0f6e08d2263/hosts",
        "LogPath": "/var/lib/docker/containers/697950c08c2e11425b1e1ea6ddc4e60fbff929e0746bb65ef328d0f6e08d2263/697950c08c2e11425b1e1ea6ddc4e60fbff929e0746bb65ef328d0f6e08d2263-json.log",
        "Name": "/tpa_vac",
        "RestartCount": 0,
        "Driver": "overlay2",
        "MountLabel": "",
        "ProcessLabel": "",
        "AppArmorProfile": "",
        "ExecIDs": null,
        "HostConfig": {
            "Binds": [
                "/tmp/zte1:/zte1:ro",
                "/tmp/zte2:/zte2:rw"
            ],
            "ContainerIDFile": "",
            "LogConfig": {
                "Type": "json-file",
                "Config": {}
            },
            "NetworkMode": "bridge",
            "PortBindings": null,
            "RestartPolicy": {
                "Name": "",
                "MaximumRetryCount": 0
            },
            "AutoRemove": false,
            "VolumeDriver": "",
            "VolumesFrom": null,
            "CapAdd": null,
            "CapDrop": null,
            "Dns": null,
            "DnsOptions": null,
            "DnsSearch": null,
            "ExtraHosts": null,
            "GroupAdd": null,
            "IpcMode": "",
            "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": null,
            "BlkioDeviceReadBps": null,
            "BlkioDeviceWriteBps": null,
            "BlkioDeviceReadIOps": null,
            "BlkioDeviceWriteIOps": null,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "Devices": null,
            "DiskQuota": 0,
            "KernelMemory": 0,
            "MemoryReservation": 0,
            "MemorySwap": 0,
            "MemorySwappiness": -1,
            "OomKillDisable": false,
            "PidsLimit": 0,
            "Ulimits": null,
            "CpuCount": 0,
            "CpuPercent": 0,
            "IOMaximumIOps": 0,
            "IOMaximumBandwidth": 0
        },
        "GraphDriver": {
            "Name": "overlay2",
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/99fdce599f2a41b6bd5eab50d363e90b22be54ca4e3167c049fd9b8896b4bedc-init/diff:/var/lib/docker/overlay2/1522f636d4e1653db28d410acc6391e68d23e6259d36935f6e71c4865f928765/diff:/var/lib/docker/overlay2/da28397beec32ac4f8e961e1afebf7610cf9781c1880ea82359f3a0c771ad663/diff:/var/lib/docker/overlay2/700209b0e540c1de67307d8c0b49c6867f13e79b34235dbaf25a9ea4c4eb2fbd/diff:/var/lib/docker/overlay2/ef3c7ba0da6f986e6dcbad105369ee468037ddbbe159f13f0ae69422a90af059/diff",
                "MergedDir": "/var/lib/docker/overlay2/99fdce599f2a41b6bd5eab50d363e90b22be54ca4e3167c049fd9b8896b4bedc/merged",
                "UpperDir": "/var/lib/docker/overlay2/99fdce599f2a41b6bd5eab50d363e90b22be54ca4e3167c049fd9b8896b4bedc/diff",
                "WorkDir": "/var/lib/docker/overlay2/99fdce599f2a41b6bd5eab50d363e90b22be54ca4e3167c049fd9b8896b4bedc/work"
            }
        },
        "Mounts": [
            {
                "Type": "bind",
                "Source": "/tmp/zte1",
                "Destination": "/zte1",
                "Mode": "ro",
                "RW": false,
                "Propagation": "rprivate"
            },
            {
                "Type": "bind",
                "Source": "/tmp/zte2",
                "Destination": "/zte2",
                "Mode": "rw",
                "RW": true,
                "Propagation": "rprivate"
            }
        ],
        "Config": {
            "Hostname": "697950c08c2e",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "Tty": true,
            "OpenStdin": true,
            "StdinOnce": false,
            "Env": [
                "DEPLOYMODE=auto/manual",
                "MSStatus=Master",
                "Image=x86_64/mpu/utelnetd:latest",
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
            ],
            "Cmd": [
                "/usr/sbin/myUtelnetd"
            ],
            "Image": "192.168.84.83:5000/x86_64/mpu/utelnetd:latest",
            "Volumes": null,
            "WorkingDir": "",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {}
        },
        "NetworkSettings": {
            "Bridge": "",
            "SandboxID": "6b0ccfc44387184e160d916091dbf55900a5700ffebe66566ec128d945987a89",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {},
            "SandboxKey": "/var/run/docker/netns/6b0ccfc44387",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "ec5e90845dd7bc9322ea56e44ad9459ee82d6b90bb63496b25cdce5f3e97eba3",
            "Gateway": "172.17.6.252",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "172.17.6.1",
            "IPPrefixLen": 24,
            "IPv6Gateway": "",
            "MacAddress": "02:42:ac:11:06:01",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "2d55e5ee8e1d1dac06484c56613273c4c9a5b6aeb9b82a1d67e5633366286e4a",
                    "EndpointID": "ec5e90845dd7bc9322ea56e44ad9459ee82d6b90bb63496b25cdce5f3e97eba3",
                    "Gateway": "172.17.6.252",
                    "IPAddress": "172.17.6.1",
                    "IPPrefixLen": 24,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:06:01"
                }
            }
        }
    }
]
[root@vac_master0 ~]#

通过 docker inspect 命令，获取 JSON 格式数据中 NetworkSettings 字段下的 SandboxKey 字段，即 /var/run/docker/netns/6b0ccfc44387。

通过将其软连接至 /var/run/netns/{容器名称} 路径后，可方便通过 ip netns 命令操作容器的网络命名空间：

[root@vac_master0 ~]# ip netns list
[root@vac_master0 ~]#
[root@vac_master0 ~]#
[root@vac_master0 ~]# ln -s /var/run/docker/netns/6b0ccfc44387 /var/run/netns/tpa_vac
[root@vac_master0 ~]# ll /var/run/netns/
total 0
lrwxrwxrwx. 1 root root 34 Feb  8 13:51 tpa_vac -> /var/run/docker/netns/6b0ccfc44387
[root@vac_master0 ~]#
[root@vac_master0 ~]#
[root@vac_master0 ~]#
[root@vac_master0 ~]# ip netns
tpa_vac (id: 0)
[root@vac_master0 ~]#