Destroying the plugin if we can't connect to it

client/driver/exec.go

@@ -37,6 +37,7 @@ type ExecDriverConfig struct {
 type execHandle struct {
 	pluginClient *plugin.Client
 	executor     plugins.Executor
+	userPid      int
 	killTimeout  time.Duration
 	logger       *log.Logger
 	waitCh       chan *cstructs.WaitResult
@@ -129,6 +130,7 @@ func (d *ExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 	// Return a driver handle
 	h := &execHandle{
 		pluginClient: pluginClient,
+		userPid:      ps.Pid,
 		executor:     executor,
 		killTimeout:  d.DriverContext.KillTimeout(task),
 		logger:       d.logger,
@@ -141,6 +143,7 @@ func (d *ExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 
 type execId struct {
 	KillTimeout  time.Duration
+	UserPid      int
 	PluginConfig *plugins.ExecutorReattachConfig
 }
 
@@ -156,6 +159,10 @@ func (d *ExecDriver) Open(ctx *ExecContext, handleID string) (DriverHandle, erro
 	}
 	executor, client, err := createExecutor(pluginConfig, d.config.LogOutput)
 	if err != nil {
+		d.logger.Println("[ERROR] error connecting to plugin so destroying plugin pid and user pid")
+		if e := destroyPlugin(id.PluginConfig.Pid, id.UserPid); e != nil {
+			d.logger.Printf("[ERROR] error destrouing plugin and userpid: %v", e)
+		}
 		return nil, fmt.Errorf("error connecting to plugin: %v", err)
 	}
 
@@ -163,6 +170,7 @@ func (d *ExecDriver) Open(ctx *ExecContext, handleID string) (DriverHandle, erro
 	h := &execHandle{
 		pluginClient: client,
 		executor:     executor,
+		userPid:      id.UserPid,
 		logger:       d.logger,
 		killTimeout:  id.KillTimeout,
 		doneCh:       make(chan struct{}),
@@ -176,6 +184,7 @@ func (h *execHandle) ID() string {
 	id := execId{
 		KillTimeout:  h.killTimeout,
 		PluginConfig: plugins.NewExecutorReattachConfig(h.pluginClient.ReattachConfig()),
+		UserPid:      h.userPid,
 	}
 
 	data, err := json.Marshal(id)

client/driver/java.go

@@ -202,6 +202,10 @@ func (d *JavaDriver) Open(ctx *ExecContext, handleID string) (DriverHandle, erro
 	}
 	executor, pluginClient, err := createExecutor(pluginConfig, d.config.LogOutput)
 	if err != nil {
+		d.logger.Println("[ERROR] error connecting to plugin so destroying plugin pid and user pid")
+		if e := destroyPlugin(id.PluginConfig.Pid, id.UserPid); e != nil {
+			d.logger.Printf("[ERROR] error destroying plugin and userpid: %v", e)
+		}
 		return nil, fmt.Errorf("error connecting to plugin: %v", err)
 	}
 

client/driver/qemu.go

@@ -248,6 +248,10 @@ func (d *QemuDriver) Open(ctx *ExecContext, handleID string) (DriverHandle, erro
 
 	executor, pluginClient, err := createExecutor(pluginConfig, d.config.LogOutput)
 	if err != nil {
+		d.logger.Println("[ERROR] error connecting to plugin so destroying plugin pid and user pid")
+		if e := destroyPlugin(id.PluginConfig.Pid, id.UserPid); e != nil {
+			d.logger.Printf("[ERROR] error destroying plugin and userpid: %v", e)
+		}
 		return nil, fmt.Errorf("error connecting to plugin: %v", err)
 	}
 

client/driver/raw_exec.go

@@ -151,6 +151,10 @@ func (d *RawExecDriver) Open(ctx *ExecContext, handleID string) (DriverHandle, e
 	}
 	executor, pluginClient, err := createExecutor(pluginConfig, d.config.LogOutput)
 	if err != nil {
+		d.logger.Println("[ERROR] error connecting to plugin so destroying plugin pid and user pid")
+		if e := destroyPlugin(id.PluginConfig.Pid, id.UserPid); e != nil {
+			d.logger.Printf("[ERROR] error destrouing plugin and userpid: %v", e)
+		}
 		return nil, fmt.Errorf("error connecting to plugin: %v", err)
 	}
 

client/driver/utils.go

@@ -3,7 +3,9 @@ package driver
 import (
 	"fmt"
 	"io"
+	"os"
 
+	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/nomad/client/driver/plugins"
 )
@@ -26,3 +28,23 @@ func createExecutor(config *plugin.ClientConfig, w io.Writer) (plugins.Executor,
 	executorPlugin := raw.(plugins.Executor)
 	return executorPlugin, executorClient, nil
 }
+
+func killProcess(pid int) error {
+	proc, err := os.FindProcess(pid)
+	if err != nil {
+		return err
+	}
+	return proc.Kill()
+}
+
+func destroyPlugin(pluginPid int, userPid int) error {
+	var merr error
+	if err := killProcess(pluginPid); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+
+	if err := killProcess(userPid); err != nil {
+		merr = multierror.Append(merr, err)
+	}
+	return merr
+}