diff --git a/compute/metadata/metadata.go b/compute/metadata/metadata.go
index f67e3c7eeae0..df915db31567 100644
--- a/compute/metadata/metadata.go
+++ b/compute/metadata/metadata.go
@@ -61,7 +61,7 @@ var (
 	instID  = &cachedValue{k: "instance/id", trim: true}
 )
 
-var defaultClient = &Client{hc: newDefaultHTTPClient()}
+var defaultClient = &client{hc: newDefaultHTTPClient()}
 
 func newDefaultHTTPClient() *http.Client {
 	return &http.Client{
@@ -88,16 +88,16 @@ func (suffix NotDefinedError) Error() string {
 	return fmt.Sprintf("metadata: GCE metadata %q not defined", string(suffix))
 }
 
-func (c *cachedValue) get(cl *Client) (v string, err error) {
+func (c *cachedValue) get(ctx context.Context, cl *client) (v string, err error) {
 	defer c.mu.Unlock()
 	c.mu.Lock()
 	if c.v != "" {
 		return c.v, nil
 	}
 	if c.trim {
-		v, err = cl.getTrimmed(context.Background(), c.k)
+		v, err = cl.getTrimmed(ctx, c.k)
 	} else {
-		v, err = cl.GetWithContext(context.Background(), c.k)
+		v, err = cl.GetWithContext(ctx, c.k)
 	}
 	if err == nil {
 		c.v = v
@@ -111,6 +111,8 @@ var (
 )
 
 // OnGCE reports whether this process is running on Google Compute Engine.
+// NOTE: True returned from `OnGCE` does not guarantee that the metadata server
+// is accessible from this process and have all the metadata defined.
 func OnGCE() bool {
 	onGCEOnce.Do(initOnGCE)
 	return onGCE
@@ -203,6 +205,8 @@ func systemInfoSuggestsGCE() bool {
 }
 
 // Subscribe calls Client.SubscribeWithContext on the default client.
+//
+// Deprecated: Please use the context aware variant [SubscribeWithContext].
 func Subscribe(suffix string, fn func(v string, ok bool) error) error {
 	return defaultClient.SubscribeWithContext(context.Background(), suffix, func(ctx context.Context, v string, ok bool) error { return fn(v, ok) })
 }
@@ -225,55 +229,188 @@ func GetWithContext(ctx context.Context, suffix string) (string, error) {
 }
 
 // ProjectID returns the current instance's project ID string.
-func ProjectID() (string, error) { return defaultClient.ProjectID() }
+//
+// Deprecated: Please use the context aware variant [ProjectIDWithContext].
+func ProjectID() (string, error) {
+	return defaultClient.ProjectIDWithContext(context.Background())
+}
+
+// ProjectIDWithContext returns the current instance's project ID string.
+func ProjectIDWithContext(ctx context.Context) (string, error) {
+	return defaultClient.ProjectIDWithContext(ctx)
+}
 
 // NumericProjectID returns the current instance's numeric project ID.
-func NumericProjectID() (string, error) { return defaultClient.NumericProjectID() }
+//
+// Deprecated: Please use the context aware variant [NumericProjectIDWithContext].
+func NumericProjectID() (string, error) {
+	return defaultClient.NumericProjectIDWithContext(context.Background())
+}
+
+// NumericProjectIDWithContext returns the current instance's numeric project ID.
+func NumericProjectIDWithContext(ctx context.Context) (string, error) {
+	return defaultClient.NumericProjectIDWithContext(ctx)
+}
 
 // InternalIP returns the instance's primary internal IP address.
-func InternalIP() (string, error) { return defaultClient.InternalIP() }
+//
+// Deprecated: Please use the context aware variant [InternalIPWithContext].
+func InternalIP() (string, error) {
+	return defaultClient.InternalIPWithContext(context.Background())
+}
+
+// InternalIPWithContext returns the instance's primary internal IP address.
+func InternalIPWithContext(ctx context.Context) (string, error) {
+	return defaultClient.InternalIPWithContext(ctx)
+}
 
 // ExternalIP returns the instance's primary external (public) IP address.
-func ExternalIP() (string, error) { return defaultClient.ExternalIP() }
+//
+// Deprecated: Please use the context aware variant [ExternalIPWithContext].
+func ExternalIP() (string, error) {
+	return defaultClient.ExternalIPWithContext(context.Background())
+}
 
-// Email calls Client.Email on the default client.
-func Email(serviceAccount string) (string, error) { return defaultClient.Email(serviceAccount) }
+// ExternalIPWithContext returns the instance's primary external (public) IP address.
+func ExternalIPWithContext(ctx context.Context) (string, error) {
+	return defaultClient.ExternalIPWithContext(ctx)
+}
+
+// Email calls Client.EmailWithContext on the default client.
+//
+// Deprecated: Please use the context aware variant [EmailWithContext].
+func Email(serviceAccount string) (string, error) {
+	return defaultClient.EmailWithContext(context.Background(), serviceAccount)
+}
+
+// EmailWithContext calls Client.EmailWithContext on the default client.
+func EmailWithContext(ctx context.Context, serviceAccount string) (string, error) {
+	return defaultClient.EmailWithContext(ctx, serviceAccount)
+}
 
 // Hostname returns the instance's hostname. This will be of the form
 // "<instanceID>.c.<projID>.internal".
-func Hostname() (string, error) { return defaultClient.Hostname() }
+//
+// Deprecated: Please use the context aware variant [HostnameWithContext].
+func Hostname() (string, error) {
+	return defaultClient.HostnameWithContext(context.Background())
+}
+
+// HostnameWithContext returns the instance's hostname. This will be of the form
+// "<instanceID>.c.<projID>.internal".
+func HostnameWithContext(ctx context.Context) (string, error) {
+	return defaultClient.HostnameWithContext(ctx)
+}
 
 // InstanceTags returns the list of user-defined instance tags,
 // assigned when initially creating a GCE instance.
-func InstanceTags() ([]string, error) { return defaultClient.InstanceTags() }
+//
+// Deprecated: Please use the context aware variant [InstanceTagsWithContext].
+func InstanceTags() ([]string, error) {
+	return defaultClient.InstanceTagsWithContext(context.Background())
+}
+
+// InstanceTagsWithContext returns the list of user-defined instance tags,
+// assigned when initially creating a GCE instance.
+func InstanceTagsWithContext(ctx context.Context) ([]string, error) {
+	return defaultClient.InstanceTagsWithContext(ctx)
+}
 
 // InstanceID returns the current VM's numeric instance ID.
-func InstanceID() (string, error) { return defaultClient.InstanceID() }
+//
+// Deprecated: Please use the context aware variant [InstanceIDWithContext].
+func InstanceID() (string, error) {
+	return defaultClient.InstanceIDWithContext(context.Background())
+}
+
+// InstanceIDWithContext returns the current VM's numeric instance ID.
+func InstanceIDWithContext(ctx context.Context) (string, error) {
+	return defaultClient.InstanceIDWithContext(ctx)
+}
 
 // InstanceName returns the current VM's instance ID string.
-func InstanceName() (string, error) { return defaultClient.InstanceName() }
+//
+// Deprecated: Please use the context aware variant [InstanceNameWithContext].
+func InstanceName() (string, error) {
+	return defaultClient.InstanceNameWithContext(context.Background())
+}
+
+// InstanceNameWithContext returns the current VM's instance ID string.
+func InstanceNameWithContext(ctx context.Context) (string, error) {
+	return defaultClient.InstanceNameWithContext(ctx)
+}
 
 // Zone returns the current VM's zone, such as "us-central1-b".
-func Zone() (string, error) { return defaultClient.Zone() }
+//
+// Deprecated: Please use the context aware variant [ZoneWithContext].
+func Zone() (string, error) {
+	return defaultClient.ZoneWithContext(context.Background())
+}
+
+// ZoneWithContext returns the current VM's zone, such as "us-central1-b".
+func ZoneWithContext(ctx context.Context) (string, error) {
+	return defaultClient.ZoneWithContext(ctx)
+}
+
+// InstanceAttributes calls Client.InstanceAttributesWithContext on the default client.
+//
+// Deprecated: Please use the context aware variant [InstanceAttributesWithContext.
+func InstanceAttributes() ([]string, error) {
+	return defaultClient.InstanceAttributesWithContext(context.Background())
+}
 
-// InstanceAttributes calls Client.InstanceAttributes on the default client.
-func InstanceAttributes() ([]string, error) { return defaultClient.InstanceAttributes() }
+// InstanceAttributesWithContext calls Client.ProjectAttributesWithContext on the default client.
+func InstanceAttributesWithContext(ctx context.Context) ([]string, error) {
+	return defaultClient.InstanceAttributesWithContext(ctx)
+}
 
-// ProjectAttributes calls Client.ProjectAttributes on the default client.
-func ProjectAttributes() ([]string, error) { return defaultClient.ProjectAttributes() }
+// ProjectAttributes calls Client.ProjectAttributesWithContext on the default client.
+//
+// Deprecated: Please use the context aware variant [ProjectAttributesWithContext].
+func ProjectAttributes() ([]string, error) {
+	return defaultClient.ProjectAttributesWithContext(context.Background())
+}
 
-// InstanceAttributeValue calls Client.InstanceAttributeValue on the default client.
+// ProjectAttributesWithContext calls Client.ProjectAttributesWithContext on the default client.
+func ProjectAttributesWithContext(ctx context.Context) ([]string, error) {
+	return defaultClient.ProjectAttributesWithContext(ctx)
+}
+
+// InstanceAttributeValue calls Client.InstanceAttributeValueWithContext on the default client.
+//
+// Deprecated: Please use the context aware variant [InstanceAttributeValueWithContext].
 func InstanceAttributeValue(attr string) (string, error) {
-	return defaultClient.InstanceAttributeValue(attr)
+	return defaultClient.InstanceAttributeValueWithContext(context.Background(), attr)
 }
 
-// ProjectAttributeValue calls Client.ProjectAttributeValue on the default client.
+// InstanceAttributeValueWithContext calls Client.InstanceAttributeValueWithContext on the default client.
+func InstanceAttributeValueWithContext(ctx context.Context, attr string) (string, error) {
+	return defaultClient.InstanceAttributeValueWithContext(ctx, attr)
+}
+
+// ProjectAttributeValue calls Client.ProjectAttributeValueWithContext on the default client.
+//
+// Deprecated: Please use the context aware variant [ProjectAttributeValueWithContext].
 func ProjectAttributeValue(attr string) (string, error) {
-	return defaultClient.ProjectAttributeValue(attr)
+	return defaultClient.ProjectAttributeValueWithContext(context.Background(), attr)
 }
 
-// Scopes calls Client.Scopes on the default client.
-func Scopes(serviceAccount string) ([]string, error) { return defaultClient.Scopes(serviceAccount) }
+// ProjectAttributeValueWithContext calls Client.ProjectAttributeValueWithContext on the default client.
+func ProjectAttributeValueWithContext(ctx context.Context, attr string) (string, error) {
+	return defaultClient.ProjectAttributeValueWithContext(ctx, attr)
+}
+
+// Scopes calls Client.ScopesWithContext on the default client.
+//
+// Deprecated: Please use the context aware variant [ScopesWithContext].
+func Scopes(serviceAccount string) ([]string, error) {
+	return defaultClient.ScopesWithContext(context.Background(), serviceAccount)
+}
+
+// ScopesWithContext calls Client.ScopesWithContext on the default client.
+func ScopesWithContext(ctx context.Context, serviceAccount string) ([]string, error) {
+	return defaultClient.ScopesWithContext(ctx, serviceAccount)
+}
 
 func strsContains(ss []string, s string) bool {
 	for _, v := range ss {
@@ -286,7 +423,7 @@ func strsContains(ss []string, s string) bool {
 
 // A Client provides metadata.
 type Client struct {
-	hc *http.Client
+	*client
 }
 
 // NewClient returns a Client that can be used to fetch metadata.
@@ -294,15 +431,20 @@ type Client struct {
 // If nil is specified, returns the default client.
 func NewClient(c *http.Client) *Client {
 	if c == nil {
-		return defaultClient
+		return &Client{client: defaultClient}
 	}
+	return &Client{client: &client{hc: c}}
+}
 
-	return &Client{hc: c}
+// client is a context aware client that provides metadata.
+// This helps to ensure we only use with context methods internally.
+type client struct {
+	hc *http.Client
 }
 
 // getETag returns a value from the metadata service as well as the associated ETag.
 // This func is otherwise equivalent to Get.
-func (c *Client) getETag(ctx context.Context, suffix string) (value, etag string, err error) {
+func (c *client) getETag(ctx context.Context, suffix string) (value, etag string, err error) {
 	// Using a fixed IP makes it very difficult to spoof the metadata service in
 	// a container, which is an important use-case for local testing of cloud
 	// deployments. To enable spoofing of the metadata service, the environment
@@ -381,19 +523,23 @@ func (c *Client) Get(suffix string) (string, error) {
 //
 // If the requested metadata is not defined, the returned error will
 // be of type NotDefinedError.
-func (c *Client) GetWithContext(ctx context.Context, suffix string) (string, error) {
+//
+// NOTE: Without an extra deadline in the context this call can take in the
+// worst case, with internal backoff retries, up to 15 seconds (e.g. when server
+// is responding slowly). Pass context with additional timeouts when needed.
+func (c *client) GetWithContext(ctx context.Context, suffix string) (string, error) {
 	val, _, err := c.getETag(ctx, suffix)
 	return val, err
 }
 
-func (c *Client) getTrimmed(ctx context.Context, suffix string) (s string, err error) {
+func (c *client) getTrimmed(ctx context.Context, suffix string) (s string, err error) {
 	s, err = c.GetWithContext(ctx, suffix)
 	s = strings.TrimSpace(s)
 	return
 }
 
-func (c *Client) lines(suffix string) ([]string, error) {
-	j, err := c.GetWithContext(context.Background(), suffix)
+func (c *client) lines(ctx context.Context, suffix string) ([]string, error) {
+	j, err := c.GetWithContext(ctx, suffix)
 	if err != nil {
 		return nil, err
 	}
@@ -405,45 +551,102 @@ func (c *Client) lines(suffix string) ([]string, error) {
 }
 
 // ProjectID returns the current instance's project ID string.
-func (c *Client) ProjectID() (string, error) { return projID.get(c) }
+//
+// Deprecated: Please use the context aware variant [Client.ProjectIDWithContext].
+func (c *Client) ProjectID() (string, error) { return c.ProjectIDWithContext(context.Background()) }
+
+// ProjectIDWithContext returns the current instance's project ID string.
+func (c *client) ProjectIDWithContext(ctx context.Context) (string, error) { return projID.get(ctx, c) }
 
 // NumericProjectID returns the current instance's numeric project ID.
-func (c *Client) NumericProjectID() (string, error) { return projNum.get(c) }
+//
+// Deprecated: Please use the context aware variant [Client.NumericProjectIDWithContext].
+func (c *Client) NumericProjectID() (string, error) {
+	return c.NumericProjectIDWithContext(context.Background())
+}
+
+// NumericProjectIDWithContext returns the current instance's numeric project ID.
+func (c *client) NumericProjectIDWithContext(ctx context.Context) (string, error) {
+	return projNum.get(ctx, c)
+}
 
 // InstanceID returns the current VM's numeric instance ID.
-func (c *Client) InstanceID() (string, error) { return instID.get(c) }
+//
+// Deprecated: Please use the context aware variant [Client.InstanceIDWithContext].
+func (c *Client) InstanceID() (string, error) {
+	return c.InstanceIDWithContext(context.Background())
+}
+
+// InstanceIDWithContext returns the current VM's numeric instance ID.
+func (c *client) InstanceIDWithContext(ctx context.Context) (string, error) {
+	return instID.get(ctx, c)
+}
 
 // InternalIP returns the instance's primary internal IP address.
+//
+// Deprecated: Please use the context aware variant [Client.InternalIPWithContext].
 func (c *Client) InternalIP() (string, error) {
-	return c.getTrimmed(context.Background(), "instance/network-interfaces/0/ip")
+	return c.InternalIPWithContext(context.Background())
+}
+
+// InternalIPWithContext returns the instance's primary internal IP address.
+func (c *client) InternalIPWithContext(ctx context.Context) (string, error) {
+	return c.getTrimmed(ctx, "instance/network-interfaces/0/ip")
 }
 
 // Email returns the email address associated with the service account.
-// The account may be empty or the string "default" to use the instance's
-// main account.
+//
+// Deprecated: Please use the context aware variant [Client.EmailWithContext].
 func (c *Client) Email(serviceAccount string) (string, error) {
+	return c.EmailWithContext(context.Background(), serviceAccount)
+}
+
+// EmailWithContext returns the email address associated with the service account.
+func (c *client) EmailWithContext(ctx context.Context, serviceAccount string) (string, error) {
 	if serviceAccount == "" {
 		serviceAccount = "default"
 	}
-	return c.getTrimmed(context.Background(), "instance/service-accounts/"+serviceAccount+"/email")
+	return c.getTrimmed(ctx, "instance/service-accounts/"+serviceAccount+"/email")
 }
 
 // ExternalIP returns the instance's primary external (public) IP address.
+//
+// Deprecated: Please use the context aware variant [Client.ExternalIPWithContext].
 func (c *Client) ExternalIP() (string, error) {
-	return c.getTrimmed(context.Background(), "instance/network-interfaces/0/access-configs/0/external-ip")
+	return c.ExternalIPWithContext(context.Background())
+}
+
+// ExternalIPWithContext returns the instance's primary external (public) IP address.
+func (c *client) ExternalIPWithContext(ctx context.Context) (string, error) {
+	return c.getTrimmed(ctx, "instance/network-interfaces/0/access-configs/0/external-ip")
 }
 
 // Hostname returns the instance's hostname. This will be of the form
 // "<instanceID>.c.<projID>.internal".
+//
+// Deprecated: Please use the context aware variant [Client.HostnameWithContext].
 func (c *Client) Hostname() (string, error) {
-	return c.getTrimmed(context.Background(), "instance/hostname")
+	return c.HostnameWithContext(context.Background())
 }
 
-// InstanceTags returns the list of user-defined instance tags,
-// assigned when initially creating a GCE instance.
+// HostnameWithContext returns the instance's hostname. This will be of the form
+// "<instanceID>.c.<projID>.internal".
+func (c *client) HostnameWithContext(ctx context.Context) (string, error) {
+	return c.getTrimmed(ctx, "instance/hostname")
+}
+
+// InstanceTags returns the list of user-defined instance tags.
+//
+// Deprecated: Please use the context aware variant [Client.InstanceTagsWithContext].
 func (c *Client) InstanceTags() ([]string, error) {
+	return c.InstanceTagsWithContext(context.Background())
+}
+
+// InstanceTagsWithContext returns the list of user-defined instance tags,
+// assigned when initially creating a GCE instance.
+func (c *client) InstanceTagsWithContext(ctx context.Context) ([]string, error) {
 	var s []string
-	j, err := c.GetWithContext(context.Background(), "instance/tags")
+	j, err := c.GetWithContext(ctx, "instance/tags")
 	if err != nil {
 		return nil, err
 	}
@@ -454,13 +657,27 @@ func (c *Client) InstanceTags() ([]string, error) {
 }
 
 // InstanceName returns the current VM's instance ID string.
+//
+// Deprecated: Please use the context aware variant [Client.InstanceNameWithContext].
 func (c *Client) InstanceName() (string, error) {
-	return c.getTrimmed(context.Background(), "instance/name")
+	return c.InstanceNameWithContext(context.Background())
+}
+
+// InstanceNameWithContext returns the current VM's instance ID string.
+func (c *client) InstanceNameWithContext(ctx context.Context) (string, error) {
+	return c.getTrimmed(ctx, "instance/name")
 }
 
 // Zone returns the current VM's zone, such as "us-central1-b".
+//
+// Deprecated: Please use the context aware variant [Client.ZoneWithContext].
 func (c *Client) Zone() (string, error) {
-	zone, err := c.getTrimmed(context.Background(), "instance/zone")
+	return c.ZoneWithContext(context.Background())
+}
+
+// ZoneWithContext returns the current VM's zone, such as "us-central1-b".
+func (c *client) ZoneWithContext(ctx context.Context) (string, error) {
+	zone, err := c.getTrimmed(ctx, "instance/zone")
 	// zone is of the form "projects/<projNum>/zones/<zoneName>".
 	if err != nil {
 		return "", err
@@ -471,12 +688,34 @@ func (c *Client) Zone() (string, error) {
 // InstanceAttributes returns the list of user-defined attributes,
 // assigned when initially creating a GCE VM instance. The value of an
 // attribute can be obtained with InstanceAttributeValue.
-func (c *Client) InstanceAttributes() ([]string, error) { return c.lines("instance/attributes/") }
+//
+// Deprecated: Please use the context aware variant [Client.InstanceAttributesWithContext].
+func (c *Client) InstanceAttributes() ([]string, error) {
+	return c.InstanceAttributesWithContext(context.Background())
+}
+
+// InstanceAttributesWithContext returns the list of user-defined attributes,
+// assigned when initially creating a GCE VM instance. The value of an
+// attribute can be obtained with InstanceAttributeValue.
+func (c *client) InstanceAttributesWithContext(ctx context.Context) ([]string, error) {
+	return c.lines(ctx, "instance/attributes/")
+}
 
 // ProjectAttributes returns the list of user-defined attributes
 // applying to the project as a whole, not just this VM.  The value of
 // an attribute can be obtained with ProjectAttributeValue.
-func (c *Client) ProjectAttributes() ([]string, error) { return c.lines("project/attributes/") }
+//
+// Deprecated: Please use the context aware variant [Client.ProjectAttributesWithContext].
+func (c *Client) ProjectAttributes() ([]string, error) {
+	return c.ProjectAttributesWithContext(context.Background())
+}
+
+// ProjectAttributesWithContext returns the list of user-defined attributes
+// applying to the project as a whole, not just this VM.  The value of
+// an attribute can be obtained with ProjectAttributeValue.
+func (c *client) ProjectAttributesWithContext(ctx context.Context) ([]string, error) {
+	return c.lines(ctx, "project/attributes/")
+}
 
 // InstanceAttributeValue returns the value of the provided VM
 // instance attribute.
@@ -486,8 +725,22 @@ func (c *Client) ProjectAttributes() ([]string, error) { return c.lines("project
 //
 // InstanceAttributeValue may return ("", nil) if the attribute was
 // defined to be the empty string.
+//
+// Deprecated: Please use the context aware variant [Client.InstanceAttributeValueWithContext].
 func (c *Client) InstanceAttributeValue(attr string) (string, error) {
-	return c.GetWithContext(context.Background(), "instance/attributes/"+attr)
+	return c.InstanceAttributeValueWithContext(context.Background(), attr)
+}
+
+// InstanceAttributeValueWithContext returns the value of the provided VM
+// instance attribute.
+//
+// If the requested attribute is not defined, the returned error will
+// be of type NotDefinedError.
+//
+// InstanceAttributeValue may return ("", nil) if the attribute was
+// defined to be the empty string.
+func (c *client) InstanceAttributeValueWithContext(ctx context.Context, attr string) (string, error) {
+	return c.GetWithContext(ctx, "instance/attributes/"+attr)
 }
 
 // ProjectAttributeValue returns the value of the provided
@@ -498,18 +751,41 @@ func (c *Client) InstanceAttributeValue(attr string) (string, error) {
 //
 // ProjectAttributeValue may return ("", nil) if the attribute was
 // defined to be the empty string.
+//
+// Deprecated: Please use the context aware variant [Client.ProjectAttributeValueWithContext].
 func (c *Client) ProjectAttributeValue(attr string) (string, error) {
-	return c.GetWithContext(context.Background(), "project/attributes/"+attr)
+	return c.ProjectAttributeValueWithContext(context.Background(), attr)
+}
+
+// ProjectAttributeValueWithContext returns the value of the provided
+// project attribute.
+//
+// If the requested attribute is not defined, the returned error will
+// be of type NotDefinedError.
+//
+// ProjectAttributeValue may return ("", nil) if the attribute was
+// defined to be the empty string.
+func (c *client) ProjectAttributeValueWithContext(ctx context.Context, attr string) (string, error) {
+	return c.GetWithContext(ctx, "project/attributes/"+attr)
 }
 
 // Scopes returns the service account scopes for the given account.
 // The account may be empty or the string "default" to use the instance's
 // main account.
+//
+// Deprecated: Please use the context aware variant [Client.ScopesWithContext].
 func (c *Client) Scopes(serviceAccount string) ([]string, error) {
+	return c.ScopesWithContext(context.Background(), serviceAccount)
+}
+
+// ScopesWithContext returns the service account scopes for the given account.
+// The account may be empty or the string "default" to use the instance's
+// main account.
+func (c *client) ScopesWithContext(ctx context.Context, serviceAccount string) ([]string, error) {
 	if serviceAccount == "" {
 		serviceAccount = "default"
 	}
-	return c.lines("instance/service-accounts/" + serviceAccount + "/scopes")
+	return c.lines(ctx, "instance/service-accounts/"+serviceAccount+"/scopes")
 }
 
 // Subscribe subscribes to a value from the metadata service.
@@ -530,7 +806,7 @@ func (c *Client) Subscribe(suffix string, fn func(v string, ok bool) error) erro
 // empty string and ok false. Subscribe blocks until fn returns a non-nil error
 // or the value is deleted. Subscribe returns the error value returned from the
 // last call to fn, which may be nil when ok == false.
-func (c *Client) SubscribeWithContext(ctx context.Context, suffix string, fn func(ctx context.Context, v string, ok bool) error) error {
+func (c *client) SubscribeWithContext(ctx context.Context, suffix string, fn func(ctx context.Context, v string, ok bool) error) error {
 	const failedSubscribeSleep = time.Second * 5
 
 	// First check to see if the metadata value exists at all.
diff --git a/compute/metadata/metadata_test.go b/compute/metadata/metadata_test.go
index 16b90db5bf2c..f53bc1b035ac 100644
--- a/compute/metadata/metadata_test.go
+++ b/compute/metadata/metadata_test.go
@@ -68,9 +68,7 @@ func TestOverrideUserAgent(t *testing.T) {
 func TestGetFailsOnBadURL(t *testing.T) {
 	ctx := context.Background()
 	c := NewClient(http.DefaultClient)
-	old := os.Getenv(metadataHostEnv)
-	defer os.Setenv(metadataHostEnv, old)
-	os.Setenv(metadataHostEnv, "host:-1")
+	t.Setenv(metadataHostEnv, "host:-1")
 	_, err := c.GetWithContext(ctx, "suffix")
 	log.Printf("%v", err)
 	if err == nil {
@@ -98,7 +96,7 @@ func TestGet_LeadingSlash(t *testing.T) {
 			ctx := context.Background()
 			ct := &captureTransport{}
 			c := NewClient(&http.Client{Transport: ct})
-			c.GetWithContext(ctx, tc.suffix)
+			_, _ = c.GetWithContext(ctx, tc.suffix)
 			if ct.url != want {
 				t.Fatalf("got %v, want %v", ct.url, want)
 			}