Speed up client startup

client/fingerprint/env_aws.go

@@ -16,9 +16,15 @@ import (
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
-// This is where the AWS metadata server normally resides. We hardcode the
-// "instance" path as well since it's the only one we access here.
-const DEFAULT_AWS_URL = "http://169.254.169.254/latest/meta-data/"
+const (
+	// This is where the AWS metadata server normally resides. We hardcode the
+	// "instance" path as well since it's the only one we access here.
+	DEFAULT_AWS_URL = "http://169.254.169.254/latest/meta-data/"
+
+	// AwsMetadataTimeout is the timeout used when contacting the AWS metadata
+	// service
+	AwsMetadataTimeout = 2 * time.Second
+)
 
 // map of instance type to approximate speed, in Mbits/s
 // Estimates from http://stackoverflow.com/a/35806587
@@ -44,16 +50,25 @@ var ec2InstanceSpeedMap = map[*regexp.Regexp]int{
 // EnvAWSFingerprint is used to fingerprint AWS metadata
 type EnvAWSFingerprint struct {
 	StaticFingerprinter
-	logger *log.Logger
+	timeout time.Duration
+	logger  *log.Logger
 }
 
 // NewEnvAWSFingerprint is used to create a fingerprint from AWS metadata
 func NewEnvAWSFingerprint(logger *log.Logger) Fingerprint {
-	f := &EnvAWSFingerprint{logger: logger}
+	f := &EnvAWSFingerprint{
+		logger:  logger,
+		timeout: AwsMetadataTimeout,
+	}
 	return f
 }
 
 func (f *EnvAWSFingerprint) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
+	// Check if we should tighten the timeout
+	if cfg.ReadBoolDefault(TightenNetworkTimeoutsConfig, false) {
+		f.timeout = 1 * time.Millisecond
+	}
+
 	if !f.isAWS() {
 		return false, nil
 	}
@@ -71,9 +86,8 @@ func (f *EnvAWSFingerprint) Fingerprint(cfg *config.Config, node *structs.Node)
 		metadataURL = DEFAULT_AWS_URL
 	}
 
-	// assume 2 seconds is enough time for inside AWS network
 	client := &http.Client{
-		Timeout:   2 * time.Second,
+		Timeout:   f.timeout,
 		Transport: cleanhttp.DefaultTransport(),
 	}
 
@@ -174,9 +188,8 @@ func (f *EnvAWSFingerprint) isAWS() bool {
 		metadataURL = DEFAULT_AWS_URL
 	}
 
-	// assume 2 seconds is enough time for inside AWS network
 	client := &http.Client{
-		Timeout:   2 * time.Second,
+		Timeout:   f.timeout,
 		Transport: cleanhttp.DefaultTransport(),
 	}
 
@@ -217,9 +230,8 @@ func (f *EnvAWSFingerprint) linkSpeed() int {
 		metadataURL = DEFAULT_AWS_URL
 	}
 
-	// assume 2 seconds is enough time for inside AWS network
 	client := &http.Client{
-		Timeout:   2 * time.Second,
+		Timeout:   f.timeout,
 		Transport: cleanhttp.DefaultTransport(),
 	}
 

client/fingerprint/env_gce.go

@@ -18,9 +18,15 @@ import (
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
-// This is where the GCE metadata server normally resides. We hardcode the
-// "instance" path as well since it's the only one we access here.
-const DEFAULT_GCE_URL = "http://169.254.169.254/computeMetadata/v1/instance/"
+const (
+	// This is where the GCE metadata server normally resides. We hardcode the
+	// "instance" path as well since it's the only one we access here.
+	DEFAULT_GCE_URL = "http://169.254.169.254/computeMetadata/v1/instance/"
+
+	// GceMetadataTimeout is the timeout used when contacting the GCE metadata
+	// service
+	GceMetadataTimeout = 2 * time.Second
+)
 
 type GCEMetadataNetworkInterface struct {
 	AccessConfigs []struct {
@@ -64,7 +70,7 @@ func NewEnvGCEFingerprint(logger *log.Logger) Fingerprint {
 
 	// assume 2 seconds is enough time for inside GCE network
 	client := &http.Client{
-		Timeout:   2 * time.Second,
+		Timeout:   GceMetadataTimeout,
 		Transport: cleanhttp.DefaultTransport(),
 	}
 
@@ -126,6 +132,11 @@ func checkError(err error, logger *log.Logger, desc string) error {
 }
 
 func (f *EnvGCEFingerprint) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
+	// Check if we should tighten the timeout
+	if cfg.ReadBoolDefault(TightenNetworkTimeoutsConfig, false) {
+		f.client.Timeout = 1 * time.Millisecond
+	}
+
 	if !f.isGCE() {
 		return false, nil
 	}

client/fingerprint/fingerprint.go

@@ -13,6 +13,10 @@ import (
 // EmptyDuration is to be used by fingerprinters that are not periodic.
 const (
 	EmptyDuration = time.Duration(0)
+
+	// TightenNetworkTimeoutsConfig is a config key that can be used during
+	// tests to tighten the timeouts for fingerprinters that make network calls.
+	TightenNetworkTimeoutsConfig = "test.tighten_network_timeouts"
 )
 
 func init() {

command/agent/testagent.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/hashicorp/nomad/api"
+	"github.com/hashicorp/nomad/client/fingerprint"
 	"github.com/hashicorp/nomad/nomad"
 	"github.com/hashicorp/nomad/nomad/structs"
 	sconfig "github.com/hashicorp/nomad/nomad/structs/config"
@@ -278,6 +279,12 @@ func (a *TestAgent) config() *Config {
 	config.Bootstrap = true
 	config.BootstrapExpect = 1
 
+	// Tighten the fingerprinter timeouts
+	if conf.Client.Options == nil {
+		conf.Client.Options = make(map[string]string)
+	}
+	conf.Client.Options[fingerprint.TightenNetworkTimeoutsConfig] = "true"
+
 	if a.ConfigCallback != nil {
 		a.ConfigCallback(conf)
 	}