docker 镜像的默认命令

如何解决docker 镜像的默认命令

如何知道容器使用基础镜像运行的默认命令，而无需实际从镜像创建新容器？

我在这里遗漏了一些概念吗？我正在使用基本映像编写 dockerfile，但我不知道在 CMD 部分放什么。

解决方法

docker image inspect <IMAGE> 将为您提供更多详细信息。

例如：

$ docker pull nginx
$ docker image inspect nginx:latest
...
"0":
  "Config": {
    ...
    "Cmd": [
      "nginx","-g","daemon off;"
    ],...
}

所以，对于 Nginx，它是 [nginx,-g,daemon off;]

或者，如果您安装了 jq，ubuntu:20.04 的输出：

$ docker pull ubuntu:20.04
$ docker image inspect ubuntu:20.04 | jq '.[0].Config.Cmd'
[
  "/bin/bash"
]

,

您始终可以在终端上执行 docker image inspect <image>，在那里您将获得大量信息。

我运行 docker image inspect busybox（只是一些随机图像），我得到以下结果

[
    {
        
        "Parent": "","Comment": "","Created": "2021-05-04T00:19:49.531663542Z","Container": "22c781af50cbbf2c31a3fb57c21d4dcfb266d6691441657088db6750d4068d22","ContainerConfig": {
            "Hostname": "22c781af50cb","Domainname": "","User": "","AttachStdin": false,"AttachStdout": false,"AttachStderr": false,"Tty": false,"OpenStdin": false,"StdinOnce": false,"Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
            ],"Cmd": [
                "/bin/sh","-c","#(nop) ","CMD [\"sh\"]"
            ],"Volumes": null,"WorkingDir": "","Entrypoint": null,"OnBuild": null,"Labels": {}
        },"DockerVersion": "19.03.12","Author": "","Config": {
            "Hostname": "","Cmd": [
                "sh"
            ],"Labels": null
        },"Architecture": "amd64","Os": "linux","Size": 1235829,"VirtualSize": 1235829,"GraphDriver": {
            "Data": {
      },"Name": "overlay2"
        },"RootFS": {
            "Type": "layers",},"Metadata": {
            "LastTagTime": "0001-01-01T00:00:00Z"
        }
    }
]

在这里您可以看到 CMD 字段