fix: remove duplicate line in known_hosts when minikube deletes

cmd/minikube/cmd/delete.go

@@ -33,6 +33,7 @@ import (
 	"github.com/docker/machine/libmachine"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
+	"k8s.io/client-go/util/homedir"
 	"k8s.io/klog/v2"
 	cmdcfg "k8s.io/minikube/cmd/minikube/cmd/config"
 	"k8s.io/minikube/pkg/drivers/kic"
@@ -48,11 +49,14 @@ import (
 	"k8s.io/minikube/pkg/minikube/kubeconfig"
 	"k8s.io/minikube/pkg/minikube/localpath"
 	"k8s.io/minikube/pkg/minikube/machine"
+	"k8s.io/minikube/pkg/minikube/mustload"
+	"k8s.io/minikube/pkg/minikube/node"
 	"k8s.io/minikube/pkg/minikube/out"
 	"k8s.io/minikube/pkg/minikube/out/register"
 	"k8s.io/minikube/pkg/minikube/reason"
 	"k8s.io/minikube/pkg/minikube/sshagent"
 	"k8s.io/minikube/pkg/minikube/style"
+	"k8s.io/minikube/pkg/util"
 )
 
 var (
@@ -233,6 +237,9 @@ func runDelete(_ *cobra.Command, args []string) {
 	defer cancel()
 
 	if deleteAll {
+		if err := deleteKnownHosts(); err != nil {
+			klog.Warningf("error deleting known hosts: %v", err)
+		}
 		deleteContainersAndVolumes(delCtx, oci.Docker)
 		deleteContainersAndVolumes(delCtx, oci.Podman)
 
@@ -723,3 +730,36 @@ func getPids(path string) ([]int, error) {
 
 	return pids, nil
 }
+
+func deleteKnownHosts() error {
+	cname := ClusterFlagValue()
+	co, err := mustload.RunningWithError(cname)
+	if err != nil {
+		return err
+	}
+	if co.CP.Host.DriverName == driver.None {
+		// none' driver does not support 'minikube ssh-host' command
+		// so nothing needs to be done
+		return nil
+	}
+	var n *config.Node
+	if nodeName == "" {
+		n = co.CP.Node
+	} else {
+		n, _, err = node.Retrieve(*co.Config, nodeName)
+		if err != nil {
+			return fmt.Errorf("node %s does not exist: %v", nodeName, err)
+		}
+	}
+	// acquire the current key line
+	keyLine, err := machine.RunSSHHostCommand(co.API, *co.Config, *n, "ssh-keyscan", []string{"-t", "rsa"})
+	if err != nil {
+		return fmt.Errorf("failed to acquire the keys: %v", err)
+	}
+
+	// remove this line from known_hosts file if it exists
+	knownHosts := filepath.Join(homedir.HomeDir(), ".ssh", "known_hosts")
+
+	return util.RemoveLineFromFile(keyLine, knownHosts)
+
+}

pkg/minikube/mustload/mustload.go

@@ -139,6 +139,56 @@ func Running(name string) ClusterController {
 	}
 }
 
+// Running is a cmd-friendly way to load a running cluster, and return an error
+// if the cluster is not running
+func RunningWithError(name string) (ClusterController, error) {
+	api, cc := Partial(name)
+
+	cp, err := config.PrimaryControlPlane(cc)
+	if err != nil {
+		return ClusterController{}, fmt.Errorf("unable to find control plane: %v", err)
+	}
+
+	machineName := config.MachineName(*cc, cp)
+	hs, err := machine.Status(api, machineName)
+	if err != nil {
+		return ClusterController{}, fmt.Errorf("unable to get machine status: %v", err)
+	}
+
+	if hs != state.Running.String() {
+		out.Styled(style.Shrug, `The control plane node is not running (state={{.state}})`, out.V{"name": cp.Name, "state": hs})
+		return ClusterController{}, fmt.Errorf("the control plane node is not running")
+	}
+
+	host, err := machine.LoadHost(api, name)
+	if err != nil {
+		return ClusterController{}, fmt.Errorf("unable to load host: %v", err)
+	}
+
+	cr, err := machine.CommandRunner(host)
+	if err != nil {
+		return ClusterController{}, fmt.Errorf("unable to get command runner: %v", err)
+	}
+
+	hostname, ip, port, err := driver.ControlPlaneEndpoint(cc, &cp, host.DriverName)
+	if err != nil {
+		return ClusterController{}, fmt.Errorf("Unable to get forwarded endpoint: %v", err)
+	}
+
+	return ClusterController{
+		API:    api,
+		Config: cc,
+		CP: ControlPlane{
+			Runner:   cr,
+			Host:     host,
+			Node:     &cp,
+			Hostname: hostname,
+			IP:       ip,
+			Port:     port,
+		},
+	}, nil
+}
+
 // Healthy is a cmd-friendly way to load a healthy cluster
 func Healthy(name string) ClusterController {
 	co := Running(name)

pkg/util/utils.go

@@ -17,11 +17,13 @@ limitations under the License.
 package util
 
 import (
+	"bufio"
 	"fmt"
 	"os"
 	"os/user"
 	"path/filepath"
 	"strconv"
+	"strings"
 
 	"github.com/blang/semver/v4"
 	units "github.com/docker/go-units"
@@ -123,3 +125,36 @@ func RemoveDuplicateStrings(initial []string) []string {
 	}
 	return result
 }
+
+// remove the specified line from the given file
+func RemoveLineFromFile(knownHostLine string, filePath string) error {
+	fd, err := os.OpenFile(filePath, os.O_CREATE|os.O_RDWR, 0666)
+	if err != nil {
+		return fmt.Errorf("failed to open %s: %v", filePath, err)
+	}
+	defer fd.Close()
+
+	// read each line from known_hosts and find theline we want to delete
+	scanner := bufio.NewScanner(fd)
+	newLines := make([]string, 0)
+	for scanner.Scan() {
+		line := string(scanner.Bytes())
+		if strings.TrimSpace(line) != strings.TrimSpace(knownHostLine) {
+			// remove the line which is identical with the key
+			newLines = append(newLines, line)
+		}
+	}
+	// remove the contents and move to the head of this file
+	fd.Truncate(0)
+	fd.Seek(0, 0)
+
+	// write the new content into the file
+
+	for _, line := range newLines {
+		if _, err := fmt.Fprintln(fd, line); err != nil {
+			return fmt.Errorf("failed to write to %s: %v", filePath, err)
+		}
+	}
+
+	return nil
+}