func TestServerMetadata(t *testing.T) {
	t.Parallel()

	choices, err := ComputeChoicesFromEnv()
	th.AssertNoErr(t, err)

	client, err := newClient()
	if err != nil {
		t.Fatalf("Unable to create a compute client: %v", err)
	}

	server, err := createServer(t, client, choices)
	if err != nil {
		t.Fatal(err)
	}
	defer servers.Delete(client, server.ID)
	if err = waitForStatus(client, server, "ACTIVE"); err != nil {
		t.Fatal(err)
	}

	metadata, err := servers.UpdateMetadata(client, server.ID, servers.MetadataOpts{
		"foo":  "bar",
		"this": "that",
	}).Extract()
	th.AssertNoErr(t, err)
	t.Logf("UpdateMetadata result: %+v\n", metadata)

	err = servers.DeleteMetadatum(client, server.ID, "foo").ExtractErr()
	th.AssertNoErr(t, err)

	metadata, err = servers.CreateMetadatum(client, server.ID, servers.MetadatumOpts{
		"foo": "baz",
	}).Extract()
	th.AssertNoErr(t, err)
	t.Logf("CreateMetadatum result: %+v\n", metadata)

	metadata, err = servers.Metadatum(client, server.ID, "foo").Extract()
	th.AssertNoErr(t, err)
	t.Logf("Metadatum result: %+v\n", metadata)
	th.AssertEquals(t, "baz", metadata["foo"])

	metadata, err = servers.Metadata(client, server.ID).Extract()
	th.AssertNoErr(t, err)
	t.Logf("Metadata result: %+v\n", metadata)

	metadata, err = servers.ResetMetadata(client, server.ID, servers.MetadataOpts{}).Extract()
	th.AssertNoErr(t, err)
	t.Logf("ResetMetadata result: %+v\n", metadata)
	th.AssertDeepEquals(t, map[string]string{}, metadata)
}

func resourceComputeInstanceV2Update(d *schema.ResourceData, meta interface{}) error {
	config := meta.(*Config)
	computeClient, err := config.computeV2Client(d.Get("region").(string))
	if err != nil {
		return fmt.Errorf("Error creating OpenStack compute client: %s", err)
	}

	var updateOpts servers.UpdateOpts
	if d.HasChange("name") {
		updateOpts.Name = d.Get("name").(string)
	}

	if updateOpts != (servers.UpdateOpts{}) {
		_, err := servers.Update(computeClient, d.Id(), updateOpts).Extract()
		if err != nil {
			return fmt.Errorf("Error updating OpenStack server: %s", err)
		}
	}

	if d.HasChange("metadata") {
		var metadataOpts servers.MetadataOpts
		metadataOpts = make(servers.MetadataOpts)
		newMetadata := d.Get("metadata").(map[string]interface{})
		for k, v := range newMetadata {
			metadataOpts[k] = v.(string)
		}

		_, err := servers.UpdateMetadata(computeClient, d.Id(), metadataOpts).Extract()
		if err != nil {
			return fmt.Errorf("Error updating OpenStack server (%s) metadata: %s", d.Id(), err)
		}
	}

	if d.HasChange("security_groups") {
		oldSGRaw, newSGRaw := d.GetChange("security_groups")
		oldSGSet := oldSGRaw.(*schema.Set)
		newSGSet := newSGRaw.(*schema.Set)
		secgroupsToAdd := newSGSet.Difference(oldSGSet)
		secgroupsToRemove := oldSGSet.Difference(newSGSet)

		log.Printf("[DEBUG] Security groups to add: %v", secgroupsToAdd)

		log.Printf("[DEBUG] Security groups to remove: %v", secgroupsToRemove)

		for _, g := range secgroupsToRemove.List() {
			err := secgroups.RemoveServerFromGroup(computeClient, d.Id(), g.(string)).ExtractErr()
			if err != nil {
				errCode, ok := err.(*gophercloud.UnexpectedResponseCodeError)
				if !ok {
					return fmt.Errorf("Error removing security group from OpenStack server (%s): %s", d.Id(), err)
				}
				if errCode.Actual == 404 {
					continue
				} else {
					return fmt.Errorf("Error removing security group from OpenStack server (%s): %s", d.Id(), err)
				}
			} else {
				log.Printf("[DEBUG] Removed security group (%s) from instance (%s)", g.(string), d.Id())
			}
		}
		for _, g := range secgroupsToAdd.List() {
			err := secgroups.AddServerToGroup(computeClient, d.Id(), g.(string)).ExtractErr()
			if err != nil {
				return fmt.Errorf("Error adding security group to OpenStack server (%s): %s", d.Id(), err)
			}
			log.Printf("[DEBUG] Added security group (%s) to instance (%s)", g.(string), d.Id())
		}

	}

	if d.HasChange("admin_pass") {
		if newPwd, ok := d.Get("admin_pass").(string); ok {
			err := servers.ChangeAdminPassword(computeClient, d.Id(), newPwd).ExtractErr()
			if err != nil {
				return fmt.Errorf("Error changing admin password of OpenStack server (%s): %s", d.Id(), err)
			}
		}
	}

	if d.HasChange("floating_ip") {
		oldFIP, newFIP := d.GetChange("floating_ip")
		log.Printf("[DEBUG] Old Floating IP: %v", oldFIP)
		log.Printf("[DEBUG] New Floating IP: %v", newFIP)
		if oldFIP.(string) != "" {
			log.Printf("[DEBUG] Attempting to disassociate %s from %s", oldFIP, d.Id())
			if err := disassociateFloatingIPFromInstance(computeClient, oldFIP.(string), d.Id(), ""); err != nil {
				return fmt.Errorf("Error disassociating Floating IP during update: %s", err)
			}
		}

		if newFIP.(string) != "" {
			log.Printf("[DEBUG] Attempting to associate %s to %s", newFIP, d.Id())
			if err := associateFloatingIPToInstance(computeClient, newFIP.(string), d.Id(), ""); err != nil {
				return fmt.Errorf("Error associating Floating IP during update: %s", err)
			}
		}
	}

	if d.HasChange("network") {
		oldNetworks, newNetworks := d.GetChange("network")
//.........这里部分代码省略.........

// UpdateMetadata updates (or creates) all the metadata specified by opts for the given server ID.
// This operation does not affect already-existing metadata that is not specified
// by opts.
func UpdateMetadata(client *gophercloud.ServiceClient, id string, opts os.UpdateMetadataOptsBuilder) os.UpdateMetadataResult {
	return os.UpdateMetadata(client, id, opts)
}