Repository: kubernetes/kubernetes
File: cmd/kubelet/app/options/options.go (Go)

Code before:
// AddFlags adds flags for a specific KubeletServer to the specified FlagSet
func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
	s.KubeletFlags.AddFlags(fs)
	AddKubeletConfigFlags(fs, &s.KubeletConfiguration)
}

// AddFlags adds flags for a specific KubeletFlags to the specified FlagSet
func (f *KubeletFlags) AddFlags(mainfs *pflag.FlagSet) {
	fs := pflag.NewFlagSet("", pflag.ExitOnError)
	defer func() {
		// Unhide deprecated flags. We want deprecated flags to show in Kubelet help.
		// We have some hidden flags, but we might as well unhide these when they are deprecated,
		// as silently deprecating and removing (even hidden) things is unkind to people who use them.
		fs.VisitAll(func(f *pflag.Flag) {
			if len(f.Deprecated) > 0 {
				f.Hidden = false
			}
		})
		mainfs.AddFlagSet(fs)
	}()

	addContainerRuntimeFlags(fs, &f.ContainerRuntimeOptions)
	f.addOSFlags(fs)

	fs.StringVar(&f.KubeletConfigFile, "config", f.KubeletConfigFile, "The Kubelet will load its initial configuration from this file. The path may be absolute or relative; relative paths start at the Kubelet's current working directory. Omit this flag to use the built-in default configuration values. Command-line flags override configuration from this file.")
	fs.StringVar(&f.KubeletDropinConfigDirectory, "config-dir", "", "Path to a directory to specify drop-ins, allows the user to optionally specify additional configs to overwrite what is provided by default and in the KubeletConfigFile flag. Note: drop-in config files must have a '.conf' suffix (e.g., '99-kubelet-address.conf'). Only files with the '.conf' extension will be loaded; all other files will be ignored. [default='']")
	fs.StringVar(&f.KubeConfig, "kubeconfig", f.KubeConfig, "Path to a kubeconfig file, specifying how to connect to the API server. Providing --kubeconfig enables API server mode, omitting --kubeconfig enables standalone mode.")

	fs.StringVar(&f.BootstrapKubeconfig, "bootstrap-kubeconfig", f.BootstrapKubeconfig, "Path to a kubeconfig file that will be used to get client certificate for kubelet. "+
		"If the file specified by --kubeconfig does not exist, the bootstrap kubeconfig is used to request a client certificate from the API server. "+
		"On success, a kubeconfig file referencing the generated client certificate and key is written to the path specified by --kubeconfig. "+
		"The client certificate and key file will be stored in the directory pointed by --cert-dir.")

	fs.StringVar(&f.HostnameOverride, "hostname-override", f.HostnameOverride, "If non-empty, will use this string as identification instead of the actual hostname.")

	fs.StringVar(&f.NodeIP, "node-ip", f.NodeIP, "IP address (or comma-separated dual-stack IP addresses) of the node. If unset, kubelet will use the node's default IPv4 address, if any, or its default IPv6 address if it has no IPv4 addresses. You can pass '::' to make it prefer the default IPv6 address rather than the default IPv4 address. If cloud-provider is set to external, this flag will help to bootstrap the node with the corresponding IP.")

	fs.StringVar(&f.CertDirectory, "cert-dir", f.CertDirectory, "The directory where the TLS certs are located. "+
		"If --tls-cert-file and --tls-private-key-file are provided, this flag will be ignored.")

	fs.StringVar(&f.CloudProvider, "cloud-provider", f.CloudProvider, "The provider for cloud services. Set to empty string for running with no cloud provider. Set to 'external' for running with an external cloud provider.")

	fs.StringVar(&f.RootDirectory, "root-dir", f.RootDirectory, "Directory path for managing kubelet files (volume mounts,etc).")
	fs.BoolVar(&f.SeccompDefault, "seccomp-default", f.SeccompDefault, "Enable the use of `RuntimeDefault` as the default seccomp profile for all workloads.")

	bindableNodeLabels := cliflag.ConfigurationMap(f.NodeLabels)
	fs.Var(&bindableNodeLabels, "node-labels", fmt.Sprintf("Labels to add when registering the node in the cluster.  Labels must be key=value pairs separated by ','. Labels in the 'kubernetes.io' namespace must begin with an allowed prefix (%s) or be in the specifically allowed set (%s)", strings.Join(kubeletapis.KubeletLabelNamespaces(), ", "), strings.Join(kubeletapis.KubeletLabels(), ", ")))

	// EXPERIMENTAL FLAGS
	fs.StringVar(&f.LockFilePath, "lock-file", f.LockFilePath, "<Warning: Alpha feature> The path to file for kubelet to use as a lock file.")
	fs.BoolVar(&f.ExitOnLockContention, "exit-on-lock-contention", f.ExitOnLockContention, "Whether kubelet should exit upon lock-file contention.")

Review comment (suggestion):
I know it is obvious and expected to have a conf ext in the drop in config dir, but this is a good to have change. 

/ok-to-test

Code after:
// AddFlags adds flags for a specific KubeletServer to the specified FlagSet
func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
	s.KubeletFlags.AddFlags(fs)
	AddKubeletConfigFlags(fs, &s.KubeletConfiguration)
}

// AddFlags adds flags for a specific KubeletFlags to the specified FlagSet
func (f *KubeletFlags) AddFlags(mainfs *pflag.FlagSet) {
	fs := pflag.NewFlagSet("", pflag.ExitOnError)
	defer func() {
		// Unhide deprecated flags. We want deprecated flags to show in Kubelet help.
		// We have some hidden flags, but we might as well unhide these when they are deprecated,
		// as silently deprecating and removing (even hidden) things is unkind to people who use them.
		fs.VisitAll(func(f *pflag.Flag) {
			if len(f.Deprecated) > 0 {
				f.Hidden = false
			}
		})
		mainfs.AddFlagSet(fs)
	}()

	addContainerRuntimeFlags(fs, &f.ContainerRuntimeOptions)
	f.addOSFlags(fs)

	fs.StringVar(&f.KubeletConfigFile, "config", f.KubeletConfigFile, "The Kubelet will load its initial configuration from this file. The path may be absolute or relative; relative paths start at the Kubelet's current working directory. Omit this flag to use the built-in default configuration values. Command-line flags override configuration from this file.")
	fs.StringVar(&f.KubeletDropinConfigDirectory, "config-dir", "", "Path to a directory containing drop-in configuration files that override settings from defaults and the --config file. The path may be absolute or relative; relative paths start at the Kubelet's current working directory. Drop-in files must have a '.conf' suffix (e.g., '99-kubelet-address.conf') and are processed in lexical order. Only '.conf' files are loaded; all other files are ignored. [default='']")
	fs.StringVar(&f.KubeConfig, "kubeconfig", f.KubeConfig, "Path to a kubeconfig file, specifying how to connect to the API server. Providing --kubeconfig enables API server mode, omitting --kubeconfig enables standalone mode.")

	fs.StringVar(&f.BootstrapKubeconfig, "bootstrap-kubeconfig", f.BootstrapKubeconfig, "Path to a kubeconfig file that will be used to get client certificate for kubelet. "+
		"If the file specified by --kubeconfig does not exist, the bootstrap kubeconfig is used to request a client certificate from the API server. "+
		"On success, a kubeconfig file referencing the generated client certificate and key is written to the path specified by --kubeconfig. "+
		"The client certificate and key file will be stored in the directory pointed by --cert-dir.")

	fs.StringVar(&f.HostnameOverride, "hostname-override", f.HostnameOverride, "If non-empty, will use this string as identification instead of the actual hostname.")

	fs.StringVar(&f.NodeIP, "node-ip", f.NodeIP, "IP address (or comma-separated dual-stack IP addresses) of the node. If unset, kubelet will use the node's default IPv4 address, if any, or its default IPv6 address if it has no IPv4 addresses. You can pass '::' to make it prefer the default IPv6 address rather than the default IPv4 address. If cloud-provider is set to external, this flag will help to bootstrap the node with the corresponding IP.")

	fs.StringVar(&f.CertDirectory, "cert-dir", f.CertDirectory, "The directory where the TLS certs are located. "+
		"If --tls-cert-file and --tls-private-key-file are provided, this flag will be ignored.")

	fs.StringVar(&f.CloudProvider, "cloud-provider", f.CloudProvider, "The provider for cloud services. Set to empty string for running with no cloud provider. Set to 'external' for running with an external cloud provider.")

	fs.StringVar(&f.RootDirectory, "root-dir", f.RootDirectory, "Directory path for managing kubelet files (volume mounts,etc).")
	fs.BoolVar(&f.SeccompDefault, "seccomp-default", f.SeccompDefault, "Enable the use of `RuntimeDefault` as the default seccomp profile for all workloads.")

	bindableNodeLabels := cliflag.ConfigurationMap(f.NodeLabels)
	fs.Var(&bindableNodeLabels, "node-labels", fmt.Sprintf("Labels to add when registering the node in the cluster.  Labels must be key=value pairs separated by ','. Labels in the 'kubernetes.io' namespace must begin with an allowed prefix (%s) or be in the specifically allowed set (%s)", strings.Join(kubeletapis.KubeletLabelNamespaces(), ", "), strings.Join(kubeletapis.KubeletLabels(), ", ")))

	// EXPERIMENTAL FLAGS
	fs.StringVar(&f.LockFilePath, "lock-file", f.LockFilePath, "<Warning: Alpha feature> The path to file for kubelet to use as a lock file.")
	fs.BoolVar(&f.ExitOnLockContention, "exit-on-lock-contention", f.ExitOnLockContention, "Whether kubelet should exit upon lock-file contention.")