Docker 容器配置详解：Config 和 HostConfig 结构体

Docker 容器的配置信息主要由两个结构体 Config 和 HostConfig 来定义，这两个结构体包含了容器创建和运行的关键参数。

1. Config 结构体

Config 结构体定义了容器的基本配置，包括镜像信息、命令、环境变量、网络配置等。

type Config struct {
	Hostname        string              // Hostname
	Domainname      string              // Domainname
	User            string              // User that will run the command(s) inside the container, also support user:group
	AttachStdin     bool                // Attach the standard input, makes possible user interaction
	AttachStdout    bool                // Attach the standard output
	AttachStderr    bool                // Attach the standard error
	ExposedPorts    nat.PortSet         `json:",omitempty"` // List of exposed ports
	Tty             bool                // Attach standard streams to a tty, including stdin if it is not closed.
	OpenStdin       bool                // Open stdin
	StdinOnce       bool                // If true, close stdin after the 1 attached client disconnects.
	Env             []string            // List of environment variable to set in the container
	Cmd             strslice.StrSlice   // Command to run when starting the container
	Healthcheck     *HealthConfig       `json:",omitempty"` // Healthcheck describes how to check the container is healthy
	ArgsEscaped     bool                `json:",omitempty"` // True if command is already escaped (meaning treat as a command line) (Windows specific).
	Image           string              // Name of the image as it was passed by the operator (e.g. could be symbolic)
	Volumes         map[string]struct{} // List of volumes (mounts) used for the container
	WorkingDir      string              // Current directory (PWD) in the command will be launched
	Entrypoint      strslice.StrSlice   // Entrypoint to run when starting the container
	NetworkDisabled bool                `json:",omitempty"` // Is network disabled
	MacAddress      string              `json:",omitempty"` // Mac Address of the container
	OnBuild         []string            // ONBUILD metadata that were defined on the image Dockerfile
	Labels          map[string]string   // List of labels set to this container
	StopSignal      string              `json:",omitempty"` // Signal to stop a container
	StopTimeout     *int                `json:",omitempty"` // Timeout (in seconds) to stop a container
	Shell           strslice.StrSlice   `json:",omitempty"` // Shell for shell-form of RUN, CMD, ENTRYPOINT
}

2. HostConfig 结构体

HostConfig 结构体定义了容器运行时的配置，包括网络模式、资源限制、重启策略、日志配置等。

type HostConfig struct {
	// Applicable to all platforms
	Binds           []string          // List of volume bindings for this container
	ContainerIDFile string            // File (path) where the containerId is written
	LogConfig       LogConfig         // Configuration of the logs for this container
	NetworkMode     NetworkMode       // Network mode to use for the container
	PortBindings    nat.PortMap       // Port mapping between the exposed port (container) and the host
	RestartPolicy   RestartPolicy     // Restart policy to be used for the container
	AutoRemove      bool              // Automatically remove container when it exits
	VolumeDriver    string            // Name of the volume driver used to mount volumes
	VolumesFrom     []string          // List of volumes to take from other container
	ConsoleSize     [2]uint           // Initial console size (height,width)
	Annotations     map[string]string `json:",omitempty"` // Arbitrary non-identifying metadata attached to container and provided to the runtime

	// Applicable to UNIX platforms
	CapAdd          strslice.StrSlice // List of kernel capabilities to add to the container
	CapDrop         strslice.StrSlice // List of kernel capabilities to remove from the container
	CgroupnsMode    CgroupnsMode      // Cgroup namespace mode to use for the container
	DNS             []string          `json:"Dns"`        // List of DNS server to lookup
	DNSOptions      []string          `json:"DnsOptions"` // List of DNSOption to look for
	DNSSearch       []string          `json:"DnsSearch"`  // List of DNSSearch to look for
	ExtraHosts      []string          // List of extra hosts
	GroupAdd        []string          // List of additional groups that the container process will run as
	IpcMode         IpcMode           // IPC namespace to use for the container
	Cgroup          CgroupSpec        // Cgroup to use for the container
	Links           []string          // List of links (in the name:alias form)
	OomScoreAdj     int               // Container preference for OOM-killing
	PidMode         PidMode           // PID namespace to use for the container
	Privileged      bool              // Is the container in privileged mode
	PublishAllPorts bool              // Should docker publish all exposed port for the container
	ReadonlyRootfs  bool              // Is the container root filesystem in read-only
	SecurityOpt     []string          // List of string values to customize labels for MLS systems, such as SELinux.
	StorageOpt      map[string]string `json:",omitempty"` // Storage driver options per container.
	Tmpfs           map[string]string `json:",omitempty"` // List of tmpfs (mounts) used for the container
	UTSMode         UTSMode           // UTS namespace to use for the container
	UsernsMode      UsernsMode        // The user namespace to use for the container
	ShmSize         int64             // Total shm memory usage
	Sysctls         map[string]string `json:",omitempty"` // List of Namespaced sysctls used for the container
	Runtime         string            `json:",omitempty"` // Runtime to use with this container

	// Applicable to Windows
	Isolation Isolation // Isolation technology of the container (e.g. default, hyperv)

	// Contains container's resources (cgroups, ulimits)
	Resources

	// Mounts specs used by the container
	Mounts []mount.Mount `json:",omitempty"`

	// MaskedPaths is the list of paths to be masked inside the container (this overrides the default set of paths)
	MaskedPaths []string

	// ReadonlyPaths is the list of paths to be set as read-only inside the container (this overrides the default set of paths)
	ReadonlyPaths []string

	// Run a custom init inside the container, if null, use the daemon's configured settings
	Init *bool `json:",omitempty"`
}

3. 容器创建后运行不会自动退出

是的，可以通过设置HostConfig结构体中的RestartPolicy字段来实现容器创建后不会自动退出。RestartPolicy字段定义了容器的重启策略，可以设置为以下几种选项之一：

'no'：不重启容器。
'always'：容器退出后总是重启。
'on-failure'：容器非正常退出时重启，可以通过设置RestartPolicy的MaximumRetryCount字段来指定最大重试次数。
'unless-stopped'：容器退出时重启，除非手动停止。

例如，可以将HostConfig结构体中的RestartPolicy字段设置为RestartPolicy{Name: "unless-stopped"}，这样容器在退出时会自动重启，除非手动停止。

总结

Config 和 HostConfig 结构体是 Docker 容器配置的关键，通过理解和运用这两个结构体，可以灵活地控制容器的创建和运行行为，满足各种不同的应用场景。