Restart Kubelet if it exits during e2e tests

test/e2e_node/e2e_service.go

@@ -87,7 +87,7 @@ func (e *E2EServices) Start() error {
 		"--manifest-path", framework.TestContext.ManifestPath,
 		"--eviction-hard", framework.TestContext.EvictionHard,
 	)
-	e.services = newServer("services", startCmd, nil, getHealthCheckURLs(), servicesLogFile)
+	e.services = newServer("services", startCmd, nil, nil, getHealthCheckURLs(), servicesLogFile, false)
 	return e.services.start()
 }
 
@@ -335,7 +335,7 @@ func (es *e2eService) startNamespaceController() error {
 }
 
 func (es *e2eService) startKubeletServer() (*server, error) {
-	var killCommand *exec.Cmd
+	var killCommand, restartCommand *exec.Cmd
 	cmdArgs := []string{}
 	if systemdRun, err := exec.LookPath("systemd-run"); err == nil {
 		// On systemd services, detection of a service / unit works reliably while
@@ -343,8 +343,9 @@ func (es *e2eService) startKubeletServer() (*server, error) {
 		// Since kubelet will typically be run as a service it also makes more
 		// sense to test it that way
 		unitName := fmt.Sprintf("kubelet-%d.service", rand.Int31())
-		cmdArgs = append(cmdArgs, systemdRun, "--unit="+unitName, getKubeletServerBin())
+		cmdArgs = append(cmdArgs, systemdRun, "--unit="+unitName, "--remain-after-exit", getKubeletServerBin())
 		killCommand = exec.Command("sudo", "systemctl", "kill", unitName)
+		restartCommand = exec.Command("sudo", "systemctl", "restart", unitName)
 		es.logFiles["kubelet.log"] = logFileData{
 			journalctlCommand: []string{"-u", unitName},
 		}
@@ -394,8 +395,10 @@ func (es *e2eService) startKubeletServer() (*server, error) {
 		"kubelet",
 		cmd,
 		killCommand,
+		restartCommand,
 		[]string{kubeletHealthCheckURL},
-		"kubelet.log")
+		"kubelet.log",
+		true)
 	return server, server.start()
 }
 
@@ -408,20 +411,32 @@ type server struct {
 	// killCommand is the command used to stop the server. It is not required. If it
 	// is not specified, `sudo kill` will be used to stop the server.
 	killCommand *exec.Cmd
+	// restartCommand is the command used to restart the server. If provided, it will be used
+	// instead of startCommand when restarting the server.
+	restartCommand *exec.Cmd
 	// healthCheckUrls is the urls used to check whether the server is ready.
 	healthCheckUrls []string
 	// outFilename is the name of the log file. The stdout and stderr of the server
 	// will be redirected to this file.
 	outFilename string
+	// restartOnExit determines whether a restart loop is launched with the server
+	restartOnExit bool
+	// Writing to this channel, if it is not nil, stops the restart loop.
+	// When tearing down a server, you should check for this channel and write to it if it exists.
+	stopRestartingCh chan<- bool
+	// Read from this to confirm that the restart loop has stopped.
+	ackStopRestartingCh <-chan bool
 }
 
-func newServer(name string, start, kill *exec.Cmd, urls []string, filename string) *server {
+func newServer(name string, start, kill, restart *exec.Cmd, urls []string, filename string, restartOnExit bool) *server {
 	return &server{
 		name:            name,
 		startCommand:    start,
 		killCommand:     kill,
+		restartCommand:  restart,
 		healthCheckUrls: urls,
 		outFilename:     filename,
+		restartOnExit:   restartOnExit,
 	}
 }
 
@@ -434,8 +449,8 @@ func commandToString(c *exec.Cmd) string {
 }
 
 func (s *server) String() string {
-	return fmt.Sprintf("server %q start-command: `%s`, kill-command: `%s`, health-check: %v, output-file: %q", s.name,
-		commandToString(s.startCommand), commandToString(s.killCommand), s.healthCheckUrls, s.outFilename)
+	return fmt.Sprintf("server %q start-command: `%s`, kill-command: `%s`, restart-command: `%s`, health-check: %v, output-file: %q", s.name,
+		commandToString(s.startCommand), commandToString(s.killCommand), commandToString(s.restartCommand), s.healthCheckUrls, s.outFilename)
 }
 
 // readinessCheck checks whether services are ready via the health check urls. Once there is
@@ -481,8 +496,23 @@ func readinessCheck(urls []string, errCh <-chan error) error {
 	return fmt.Errorf("e2e service readiness check timeout %v", *serverStartTimeout)
 }
 
+// Note: restartOnExit == true requires len(s.healthCheckUrls) > 0 to work properly.
 func (s *server) start() error {
 	errCh := make(chan error)
+
+	var stopRestartingCh, ackStopRestartingCh chan bool
+	if s.restartOnExit {
+		if len(s.healthCheckUrls) == 0 {
+			return fmt.Errorf("Tried to start %s which has s.restartOnExit == true, but no health check urls provided.", s)
+		}
+
+		stopRestartingCh = make(chan bool)
+		ackStopRestartingCh = make(chan bool)
+
+		s.stopRestartingCh = stopRestartingCh
+		s.ackStopRestartingCh = ackStopRestartingCh
+	}
+
 	go func() {
 		defer close(errCh)
 
@@ -496,10 +526,9 @@ func (s *server) start() error {
 		defer outfile.Close()
 		defer outfile.Sync()
 
-		cmd := s.startCommand
 		// Set the command to write the output file
-		cmd.Stdout = outfile
-		cmd.Stderr = outfile
+		s.startCommand.Stdout = outfile
+		s.startCommand.Stderr = outfile
 
 		// Death of this test process should kill the server as well.
 		attrs := &syscall.SysProcAttr{}
@@ -511,14 +540,96 @@ func (s *server) start() error {
 			errCh <- fmt.Errorf("failed to set Pdeathsig field (non-linux build)")
 			return
 		}
-		cmd.SysProcAttr = attrs
+		s.startCommand.SysProcAttr = attrs
 
-		// Run the command
-		err = cmd.Run()
+		// Start the command
+		err = s.startCommand.Start()
 		if err != nil {
-			errCh <- fmt.Errorf("failed to run server start command %q: %v", commandToString(cmd), err)
+			errCh <- fmt.Errorf("failed to run %s: %v", s, err)
 			return
 		}
+		if !s.restartOnExit {
+			// If we aren't planning on restarting, ok to Wait() here to release resources.
+			// Otherwise, we Wait() in the restart loop.
+			err = s.startCommand.Wait()
+			if err != nil {
+				errCh <- fmt.Errorf("failed to run %s: %v", s, err)
+				return
+			}
+		} else {
+			// New stuff
+			usedStartCmd := true
+			for {
+				// Wait for an initial health check to pass, so that we are sure the server started.
+				err := readinessCheck(s.healthCheckUrls, nil)
+				if err != nil {
+					if usedStartCmd {
+						s.startCommand.Wait() // Release resources if necessary.
+					}
+					// This should not happen, immediately stop the e2eService process.
+					glog.Fatalf("restart loop readinessCheck failed for %s", s)
+				}
+
+				// Initial health check passed, wait until a health check fails again.
+			stillAlive:
+				for {
+					select {
+					case <-stopRestartingCh:
+						ackStopRestartingCh <- true
+						return
+					case <-time.After(time.Second):
+						for _, url := range s.healthCheckUrls {
+							resp, err := http.Get(url)
+							if err != nil || resp.StatusCode != http.StatusOK {
+								break stillAlive
+							}
+						}
+					}
+				}
+
+				if usedStartCmd {
+					s.startCommand.Wait() // Release resources from last cmd
+					usedStartCmd = false
+				}
+				if s.restartCommand != nil {
+					// Always make a fresh copy of restartCommand before running, we may have to restart multiple times
+					s.restartCommand = &exec.Cmd{
+						Path:        s.restartCommand.Path,
+						Args:        s.restartCommand.Args,
+						Env:         s.restartCommand.Env,
+						Dir:         s.restartCommand.Dir,
+						Stdin:       s.restartCommand.Stdin,
+						Stdout:      s.restartCommand.Stdout,
+						Stderr:      s.restartCommand.Stderr,
+						ExtraFiles:  s.restartCommand.ExtraFiles,
+						SysProcAttr: s.restartCommand.SysProcAttr,
+					}
+					err = s.restartCommand.Run() // Run and wait for exit. This command is assumed to have short duration, e.g. systemctl restart
+					if err != nil {
+						// This should not happen, immediately stop the e2eService process.
+						glog.Fatalf("restarting %s with restartCommand failed. Error: %v.", s, err)
+					}
+				} else {
+					s.startCommand = &exec.Cmd{
+						Path:        s.startCommand.Path,
+						Args:        s.startCommand.Args,
+						Env:         s.startCommand.Env,
+						Dir:         s.startCommand.Dir,
+						Stdin:       s.startCommand.Stdin,
+						Stdout:      s.startCommand.Stdout,
+						Stderr:      s.startCommand.Stderr,
+						ExtraFiles:  s.startCommand.ExtraFiles,
+						SysProcAttr: s.startCommand.SysProcAttr,
+					}
+					err = s.startCommand.Start()
+					usedStartCmd = true
+					if err != nil {
+						// This should not happen, immediately stop the e2eService process.
+						glog.Fatalf("restarting %s with startCommand failed. Error: %v.", s, err)
+					}
+				}
+			}
+		}
 	}()
 
 	return readinessCheck(s.healthCheckUrls, errCh)
@@ -528,6 +639,12 @@ func (s *server) kill() error {
 	name := s.name
 	cmd := s.startCommand
 
+	// If s has a restart loop, turn it off.
+	if s.restartOnExit {
+		s.stopRestartingCh <- true
+		<-s.ackStopRestartingCh
+	}
+
 	if s.killCommand != nil {
 		return s.killCommand.Run()
 	}