Add --disable-coredns-log flag (kubernetes#20992)

Author: sugymt

cmd/minikube/cmd/start_flags.go

@@ -139,6 +139,7 @@ const (
 	binaryMirror            = "binary-mirror"
 	disableOptimizations    = "disable-optimizations"
 	disableMetrics          = "disable-metrics"
+	disableCoreDNSLog       = "disable-coredns-log"
 	qemuFirmwarePath        = "qemu-firmware-path"
 	socketVMnetClientPath   = "socket-vmnet-client-path"
 	socketVMnetPath         = "socket-vmnet-path"
@@ -206,6 +207,7 @@ func initMinikubeFlags() {
 	startCmd.Flags().String(binaryMirror, "", "Location to fetch kubectl, kubelet, & kubeadm binaries from.")
 	startCmd.Flags().Bool(disableOptimizations, false, "If set, disables optimizations that are set for local Kubernetes. Including decreasing CoreDNS replicas from 2 to 1. Defaults to false.")
 	startCmd.Flags().Bool(disableMetrics, false, "If set, disables metrics reporting (CPU and memory usage), this can improve CPU usage. Defaults to false.")
+	startCmd.Flags().Bool(disableCoreDNSLog, false, "If set, disable CoreDNS verbose logging. Defaults to false.")
 	startCmd.Flags().String(staticIP, "", "Set a static IP for the minikube cluster, the IP must be: private, IPv4, and the last octet must be between 2 and 254, for example 192.168.200.200 (Docker and Podman drivers only)")
 	startCmd.Flags().StringP(gpus, "g", "", "Allow pods to use your GPUs. Options include: [all,nvidia,amd] (Docker driver with Docker container-runtime only)")
 	startCmd.Flags().Duration(autoPauseInterval, time.Minute*1, "Duration of inactivity before the minikube VM is paused (default 1m0s)")
@@ -625,6 +627,7 @@ func generateNewConfigFromFlags(cmd *cobra.Command, k8sVersion string, rtime str
 		BinaryMirror:            viper.GetString(binaryMirror),
 		DisableOptimizations:    viper.GetBool(disableOptimizations),
 		DisableMetrics:          viper.GetBool(disableMetrics),
+		DisableCoreDNSLog:       viper.GetBool(disableCoreDNSLog),
 		CustomQemuFirmwarePath:  viper.GetString(qemuFirmwarePath),
 		SocketVMnetClientPath:   detect.SocketVMNetClientPath(),
 		SocketVMnetPath:         detect.SocketVMNetPath(),

pkg/minikube/config/types.go

@@ -101,6 +101,7 @@ type ClusterConfig struct {
 	BinaryMirror            string // Mirror location for kube binaries (kubectl, kubelet, & kubeadm)
 	DisableOptimizations    bool
 	DisableMetrics          bool
+	DisableCoreDNSLog       bool
 	CustomQemuFirmwarePath  string
 	SocketVMnetClientPath   string
 	SocketVMnetPath         string

pkg/minikube/node/start.go

@@ -956,11 +956,15 @@ func addCoreDNSEntry(runner command.Runner, name, ip string, cc config.ClusterCo
 		sed = fmt.Sprintf("sed -e '/^        hosts {.*/a \\           %s %s'", ip, name)
 	}
 
-	// check if logging is already enabled (via log plugin) in coredns configmap, so not to duplicate it
-	regex := regexp.MustCompile(`(?smU)^ *log *$`)
-	if !regex.MatchString(cm) {
-		// inject log plugin into coredns configmap
-		sed = fmt.Sprintf("%s -e '/^        errors *$/i \\        log'", sed)
+	if cc.DisableCoreDNSLog {
+		sed = fmt.Sprintf("%s -e '/^        log *$/d'", sed)
+	} else {
+		// check if logging is already enabled (via log plugin) in coredns configmap, so not to duplicate it
+		regex := regexp.MustCompile(`(?smU)^ *log *$`)
+		if !regex.MatchString(cm) {
+			// inject log plugin into coredns configmap
+			sed = fmt.Sprintf("%s -e '/^        errors *$/i \\        log'", sed)
+		}
 	}
 
 	// replace coredns configmap via kubectl