delete older minikube version preload files on start tup

cmd/minikube/cmd/delete.go

@@ -40,6 +40,7 @@ import (
 	"k8s.io/minikube/pkg/minikube/constants"
 	"k8s.io/minikube/pkg/minikube/cruntime"
 	"k8s.io/minikube/pkg/minikube/delete"
+	"k8s.io/minikube/pkg/minikube/download"
 	"k8s.io/minikube/pkg/minikube/driver"
 	"k8s.io/minikube/pkg/minikube/exit"
 	"k8s.io/minikube/pkg/minikube/kubeconfig"
@@ -151,7 +152,7 @@ func runDelete(cmd *cobra.Command, args []string) {
 	}
 	// register.SetEventLogPath(localpath.EventLog(ClusterFlagValue()))
 	register.Reg.SetStep(register.Deleting)
-
+	download.CleanUpOlderPreloads()
 	validProfiles, invalidProfiles, err := config.ListProfiles()
 	if err != nil {
 		klog.Warningf("'error loading profiles in minikube home %q: %v", localpath.MiniPath(), err)

cmd/minikube/cmd/start.go

@@ -142,6 +142,7 @@ func runStart(cmd *cobra.Command, args []string) {
 	}
 	defer pkgtrace.Cleanup()
 	displayVersion(version.GetVersion())
+	go download.CleanUpOlderPreloads()
 
 	// No need to do the update check if no one is going to see it
 	if !viper.GetBool(interactive) || !viper.GetBool(dryRun) {

pkg/minikube/download/preload.go

@@ -21,9 +21,12 @@ import (
 	"crypto/md5"
 	"encoding/hex"
 	"fmt"
+	"io/ioutil"
 	"net/http"
 	"os"
+	"path"
 	"path/filepath"
+	"strings"
 
 	"cloud.google.com/go/storage"
 	"google.golang.org/api/option"
@@ -282,3 +285,26 @@ var ensureChecksumValid = func(k8sVersion, containerRuntime, targetPath string,
 
 	return nil
 }
+
+// CleanUpOlderPreloads deletes preload files beloning to older minikube versions
+// checks the current preload version and then if the saved tar file is belongs to older minikube it will delete it
+// in case of failure only logs to the user
+func CleanUpOlderPreloads() {
+	files, err := ioutil.ReadDir(targetDir())
+	if err != nil {
+		klog.Warningf("Failed to list prelaod files: %v", err)
+	}
+
+	for _, file := range files {
+		ver := strings.Split(file.Name(), "-")[3]
+
+		if ver != PreloadVersion {
+			fn := path.Join(targetDir(), file.Name())
+			klog.Infof("deleting older generation preload %s", fn)
+			err := os.Remove(fn)
+			if err != nil {
+				klog.Warningf("Failed to clean up older preload files, consider running `minikube delete --all --purge`")
+			}
+		}
+	}
+}