Specify DHCP domain for hostname

In 9a8c6db448, we looked at the hostname
in the metadata service and used '.' as the delimiter to chop off the
dhcp_domain (specified in nova.conf). However administrators need to
better control the dhcp domain better as there may be a '.' in the host
name itself. So let's introduce a config option that we can use and
default it to what nova uses when dhcp_domain is not specified which is
"novalocal"

pkg/cloudprovider/providers/openstack/openstack.go

@@ -121,6 +121,7 @@ type RouterOpts struct {
 type MetadataOpts struct {
 	SearchOrder    string     `gcfg:"search-order"`
 	RequestTimeout MyDuration `gcfg:"request-timeout"`
+	DHCPDomain     string     `gcfg:"dhcp-domain"`
 }
 
 // OpenStack is an implementation of cloud provider Interface for OpenStack.
@@ -233,6 +234,7 @@ func configFromEnv() (cfg Config, ok bool) {
 			cfg.Global.TrustID != "")
 
 	cfg.Metadata.SearchOrder = fmt.Sprintf("%s,%s", configDriveID, metadataID)
+	cfg.Metadata.DHCPDomain = "novalocal"
 	cfg.BlockStorage.BSVersion = "auto"
 
 	return
@@ -250,6 +252,7 @@ func readConfig(config io.Reader) (Config, error) {
 	cfg.BlockStorage.TrustDevicePath = false
 	cfg.BlockStorage.IgnoreVolumeAZ = false
 	cfg.Metadata.SearchOrder = fmt.Sprintf("%s,%s", configDriveID, metadataID)
+	cfg.Metadata.DHCPDomain = "novalocal"
 
 	err := gcfg.ReadInto(&cfg, config)
 	return cfg, err

pkg/cloudprovider/providers/openstack/openstack_instances.go

@@ -61,6 +61,10 @@ func (i *Instances) CurrentNodeName(ctx context.Context, hostname string) (types
 	if err != nil {
 		return "", err
 	}
+	domain := "." + i.opts.DHCPDomain
+	if i.opts.DHCPDomain != "" && strings.HasSuffix(md.Hostname, domain) {
+		return types.NodeName(strings.TrimSuffix(md.Hostname, domain)), nil
+	}
 	return types.NodeName(strings.Split(md.Hostname, ".")[0]), nil
 }