Add 'pid_file' config option

command/server.go

@@ -659,6 +659,18 @@ CLUSTER_SYNTHESIS_COMPLETE:
 	// Release the log gate.
 	c.logGate.Flush()
 
+	// Write out the PID to the file now that server has successfully started
+	if err := c.storePidFile(config.PidFile); err != nil {
+		c.Ui.Output(fmt.Sprintf("Error storing PID: %v", err))
+		return 1
+	}
+
+	defer func() {
+		if err := c.removePidFile(config.PidFile); err != nil {
+			c.Ui.Output(fmt.Sprintf("Error deleting the PID file: %v", err))
+		}
+	}()
+
 	// Wait for shutdown
 	shutdownTriggered := false
 
@@ -1225,6 +1237,37 @@ func (c *ServerCommand) AutocompleteFlags() complete.Flags {
 	}
 }
 
+// storePidFile is used to write out our PID to a file if necessary
+func (c *ServerCommand) storePidFile(pidPath string) error {
+	// Quit fast if no pidfile
+	if pidPath == "" {
+		return nil
+	}
+
+	// Open the PID file
+	pidFile, err := os.OpenFile(pidPath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0666)
+	if err != nil {
+		return fmt.Errorf("could not open pid file: %v", err)
+	}
+	defer pidFile.Close()
+
+	// Write out the PID
+	pid := os.Getpid()
+	_, err = pidFile.WriteString(fmt.Sprintf("%d", pid))
+	if err != nil {
+		return fmt.Errorf("could not write to pid file: %v", err)
+	}
+	return nil
+}
+
+// removePidFile is used to cleanup the PID file if necessary
+func (c *ServerCommand) removePidFile(pidPath string) error {
+	if pidPath == "" {
+		return nil
+	}
+	return os.Remove(pidPath)
+}
+
 // MakeShutdownCh returns a channel that can be used for shutdown
 // notifications for commands. This channel will send a message for every
 // SIGINT or SIGTERM received.

command/server/config.go

@@ -46,6 +46,8 @@ type Config struct {
 	ClusterCipherSuites string `hcl:"cluster_cipher_suites"`
 
 	PluginDirectory string `hcl:"plugin_directory"`
+
+	PidFile string `hcl:"pid_file"`
 }
 
 // DevConfig is a Config that is used for dev mode of Vault.
@@ -293,6 +295,11 @@ func (c *Config) Merge(c2 *Config) *Config {
 		result.PluginDirectory = c2.PluginDirectory
 	}
 
+	result.PidFile = c.PidFile
+	if c2.PidFile != "" {
+		result.PidFile = c2.PidFile
+	}
+
 	return result
 }
 
@@ -385,6 +392,7 @@ func ParseConfig(d string, logger log.Logger) (*Config, error) {
 		"cluster_name",
 		"cluster_cipher_suites",
 		"plugin_directory",
+		"pid_file",
 	}
 	if err := checkHCLKeys(list, valid); err != nil {
 		return nil, err

command/server/config_test.go

@@ -67,6 +67,8 @@ func TestLoadConfigFile(t *testing.T) {
 		DefaultLeaseTTL:    10 * time.Hour,
 		DefaultLeaseTTLRaw: "10h",
 		ClusterName:        "testcluster",
+
+		PidFile: "./pidfile",
 	}
 	if !reflect.DeepEqual(config, expected) {
 		t.Fatalf("expected \n\n%#v\n\n to be \n\n%#v\n\n", config, expected)
@@ -129,6 +131,7 @@ func TestLoadConfigFile_json(t *testing.T) {
 		DisableMlockRaw:    interface{}(nil),
 		EnableUI:           true,
 		EnableUIRaw:        true,
+		PidFile:            "./pidfile",
 	}
 	if !reflect.DeepEqual(config, expected) {
 		t.Fatalf("expected \n\n%#v\n\n to be \n\n%#v\n\n", config, expected)

command/server/test-fixtures/config.hcl

@@ -28,3 +28,5 @@ telemetry {
 max_lease_ttl = "10h"
 default_lease_ttl = "10h"
 cluster_name = "testcluster"
+
+pid_file = "./pidfile"

command/server/test-fixtures/config.hcl.json

@@ -17,5 +17,6 @@
 	"max_lease_ttl": "10h",
 	"default_lease_ttl": "10h",
 	"cluster_name":"testcluster",
-	"ui":true
+	"ui":true,
+	"pid_file":"./pidfile"
 }

website/source/docs/configuration/index.html.md

@@ -105,6 +105,9 @@ to specify where the configuration is.
   the standard Vault API address will automatically redirect there. This can also
   be provided via the environment variable `VAULT_UI`.
 
+- `pid_file` `(string: "")` - Path to the file in which Vault server PID should
+  be stored.
+
 [storage-backend]: /docs/configuration/storage/index.html
 [listener]: /docs/configuration/listener/index.html
 [telemetry]: /docs/configuration/telemetry.html