池中“已存在”

Question

我启动MySQL码头并运行良好：

 docker run -d `
     --network todo-app --network-alias mysql `
     -v todo-mysql-data:/var/lib/mysql `
     -e MYSQL_ROOT_PASSWORD=secret `
     -e MYSQL_DATABASE=todos `
     mysql:5.7

但是69692152171a: Already exists线是什么意思呢？命令docker images没有为id 69692152171a带来任何东西。

Unable to find image 'mysql:5.7' locally
5.7: Pulling from library/mysql
69692152171a: Already exists
1651b0be3df3: Pull complete
951da7386bc8: Pull complete
0f86c95aa242: Pull complete
37ba2d8bd4fe: Pull complete
6d278bb05e94: Pull complete
497efbd93a3e: Pull complete
a023ae82eef5: Pull complete
e76c35f20ee7: Pull complete
e887524d2ef9: Pull complete
ccb65627e1c3: Pull complete

下面的UPD是从docker image inspect mysql:5.7输出的，但是没有任何关于69692152171a的内容。

[
    {
        "Id": "sha256:2c9028880e5814e8923c278d7e2059f9066d56608a21cd3f83a01e3337bacd68",
        "RepoTags": [
            "mysql:5.7"
        ],
        "RepoDigests": [
            "mysql@sha256:a682e3c78fc5bd941e9db080b4796c75f69a28a8cad65677c23f7a9f18ba21fa"
        ],
        "Parent": "",
        "Comment": "",
        "Created": "2021-05-12T08:11:03.343403499Z",
        "Container": "db38503d38cc5342a2e11abace95c67ea3cc8bb65b48d45bfcda4bcb30748245",
        "ContainerConfig": {
            "Hostname": "db38503d38cc",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "3306/tcp": {},
                "33060/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "GOSU_VERSION=1.12",
                "MYSQL_MAJOR=5.7",
                "MYSQL_VERSION=5.7.34-1debian10"
            ],
            "Cmd": [
                "/bin/sh",
                "-c",
                "#(nop) ",
                "CMD [\"mysqld\"]"
            ],
            "Image": "sha256:4b62934a5405f45c27bf212c6289792743498ce4ff0a5e0f1cdf6b6371320fbf",
            "Volumes": {
                "/var/lib/mysql": {}
            },
            "WorkingDir": "",
            "Entrypoint": [
                "docker-entrypoint.sh"
            ],
            "OnBuild": null,
            "Labels": {}
        },
        "DockerVersion": "19.03.12",
        "Author": "",
        "Config": {
            "Hostname": "",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "3306/tcp": {},
                "33060/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "GOSU_VERSION=1.12",
                "MYSQL_MAJOR=5.7",
                "MYSQL_VERSION=5.7.34-1debian10"
            ],
            "Cmd": [
                "mysqld"
            ],
            "Image": "sha256:4b62934a5405f45c27bf212c6289792743498ce4ff0a5e0f1cdf6b6371320fbf",
            "Volumes": {
                "/var/lib/mysql": {}
            },
            "WorkingDir": "",
            "Entrypoint": [
                "docker-entrypoint.sh"
            ],
            "OnBuild": null,
            "Labels": null
        },
        "Architecture": "amd64",
        "Os": "linux",
        "Size": 446995706,
        "VirtualSize": 446995706,
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/4b355447174887cc24e9c4ce3d03bf66a43f9f12933a51d67447e6e7d3440f68/diff:/var/lib/docker/overlay2/4a933d2f6392c6e7a6bde1a2ec07796647afb48bfd3786a0487814787bcc2e6b/diff:/var/lib/docker/overlay2/dc24d83df2f1b4125d5541e576a18e4f1fabf4aa51ffb55e1670055a3a7765aa/diff:/var/lib/docker/overlay2/28c38b6e267cc02a806eb033998d90d5483e875283993bf15ebd6fb676445aa4/diff:/var/lib/docker/overlay2/8b98e54ac5867901dfb899acd5c8c945f5ea98f69bc99ed4283cbbe5fd1a5b5e/diff:/var/lib/docker/overlay2/c974a8bac2ab3fb407d73d379d1fd8e3ad2d5d37bd84d259aaf5d19dd8e4bb20/diff:/var/lib/docker/overlay2/cf85ba34d9447973763b63e81351759ad4665a182bd42a12f2bf01416cb6236e/diff:/var/lib/docker/overlay2/9dfb686f6a4c9bb5aac551ff50f6c89493e5d37229e8d0a90f1725a4a97b98eb/diff:/var/lib/docker/overlay2/ccbe6e85c920f45001435c90f2bd95d432e2908804631901c6eb00b0290e3a25/diff:/var/lib/docker/overlay2/39c609a115068695fe652ebe45e382b7a9b8651eaf9b9d0a1db631f4ca4352f9/diff",
                "MergedDir": "/var/lib/docker/overlay2/8acf9c4dcbc0241cdb938b766c1035c69716b44617ef8105ae5845ad70189ef8/merged",
                "UpperDir": "/var/lib/docker/overlay2/8acf9c4dcbc0241cdb938b766c1035c69716b44617ef8105ae5845ad70189ef8/diff",
                "WorkDir": "/var/lib/docker/overlay2/8acf9c4dcbc0241cdb938b766c1035c69716b44617ef8105ae5845ad70189ef8/work"
            },
            "Name": "overlay2"
        },
        "RootFS": {
            "Type": "layers",
            "Layers": [
                "sha256:02c055ef67f5904019f43a41ea5f099996d8e7633749b6e606c400526b2c4b33",
                "sha256:14be0d40572c9e789898075dab874a65268de67962d8fd775172b206a9305022",
                "sha256:e82f328cb5e68d3c0fcc6604b3c09a2898d94fde76f589abc5163c85e168a075",
                "sha256:b2abc2ad4a418fb408384c726f800fa1f722cbb38987200cd362bc73f20cc988",
                "sha256:570df12e998cd93e68915a6de7002f9ca1e4b21bbaca3cd1124b7770c800b1b4",
                "sha256:ae477702a51387de5407cbaad4e225c3b3ddfb329cb1b00739b4161fe34d80a6",
                "sha256:3182d4b853f01f95a1cc30cd97c3e5e4d1aa3011ba4cf6273c2d5b38ef1adba0",
                "sha256:940ffd6ceda5ac47aeabf50a3210969f1adce1a78b1dd66dab62c20a2c58caa5",
                "sha256:d329e0888b830d8de863fedf17cb8e600f46ff869b82a43d92499fceb7797bf8",
                "sha256:516d3b88eaf6e98711593913e66d73b14c4438aeec0ca57e6378823e7423ec6d",
                "sha256:8dd710df810d11d75e69cfd8dd0db15ebdd13a667069db0638b9d3168218b3f4"
            ]
        },
        "Metadata": {
            "LastTagTime": "0001-01-01T00:00:00Z"
        }
    }
]

Answer 1

id 69692152171a是映像的第一层，因为您可能有另一个版本的mysql本地版本，该版本与此层具有相同的层，因此当您拉出图像时，此消息69692152171a: Already exists意味着该层在不同版本之间没有任何更改。

要查看图像的层，请运行docker image inspect mysql:5.7

您可以在这里阅读更多内容：https://docs.docker.com/engine/reference/commandline/pull/#examples