liquidapi: enhance OSTypeProber to support kvm_ostype

liquidapi/constants.go

@@ -8,7 +8,7 @@ import (
 )
 
 // The following list of regexes is derived from a hardcoded list of valid values
-// for an image's "vmware_ostype" attribute in Nova/Glance. This list was copied from
+// for an image's "vmware_ostype" and "kvm_ostype" attributes in Nova/Glance. This list was copied from
 // https://github.com/openstack/nova/blob/master/nova/virt/vmwareapi/constants.py
 // and the comment over there says:
 //
@@ -21,9 +21,9 @@ import (
 // OSTypeProber. Therefore, we replaced all obvious version numbers in the valid
 // values with placeholders, so that this does not break as easily in the future.
 // We do not recommend utilizing this regex list for anything else other than
-// validating the "vmware_ostype" attribute on existing images.
+// validating the "vmware_ostype" and "kvm_ostype" attributes on existing images.
 
-var isValidVMwareOSTypeRegex = []*regexp.Regexp{
+var isValidOSTypeRegex = []*regexp.Regexp{
 	regexp.MustCompile(`^almalinux_64Guest$`),
 	regexp.MustCompile(`^amazonlinux(\d+)_64Guest$`),
 	regexp.MustCompile(`^asianux(\d+)_64Guest$`),

liquidapi/constants_test.go

@@ -12,7 +12,7 @@ import (
 // so that we ensure our regexes catch all cases. Version updates should not
 // break this, only "net-new" OS types will break the test.
 
-func TestIsValidVMwareOSType(t *testing.T) {
+func TestIsValidOSType(t *testing.T) {
 	var versionsToCheck = []string{
 		"almalinux_64Guest",
 		"amazonlinux2_64Guest",
@@ -211,12 +211,12 @@ func TestIsValidVMwareOSType(t *testing.T) {
 	}
 	for _, versionToCheck := range versionsToCheck {
 		t.Run(versionToCheck, func(t *testing.T) {
-			for _, regex := range isValidVMwareOSTypeRegex {
+			for _, regex := range isValidOSTypeRegex {
 				if regex.MatchString(versionToCheck) {
 					return
 				}
 			}
-			t.Fatal(`version "` + versionToCheck + `" is not valid according to any of the regexes in isValidVMwareOSTypeRegex, but it should be`)
+			t.Fatal(`version "` + versionToCheck + `" is not valid according to any of the regexes in isValidOSTypeRegex, but it should be`)
 		})
 	}
 }

liquidapi/ostype_prober.go

@@ -28,6 +28,8 @@ import (
 //   - "image-unknown", if no valid image reference exists in the instance metadata
 //   - "image-deleted", if the image has been deleted since the instance was booted
 //   - the value in the "vmware_ostype" attribute on the image metadata, if that field exists and the value is valid
+//   - the value in the "kvm_ostype" attribute on the image metadata, if that field exists and the value is valid
+//   - the value in the "properties.os_distro" attribute on the image metadata, if that field exists and the value is valid
 //   - "$TYPE", if the image metadata contains a tag of the form "ostype:$TYPE"
 //   - "unknown", if no other rule matches
 //
@@ -37,6 +39,7 @@ import (
 //   - "rootdisk-missing", if the boot volume has an empty ID
 //   - "rootdisk-inspect-error", if the boot volume cannot be located or if its metadata cannot be inspected in Glance
 //   - the value in the "volume_image_metadata.vmware_ostype" attribute on the volume metadata, if that field exists and the value is valid
+//   - the value in the "volume_image_metadata.kvm_ostype" attribute on the volume metadata, if that field exists and the value is valid
 //   - "unknown", if no other rule matches
 type OSTypeProber struct {
 	// caches for repeated queries
@@ -150,25 +153,32 @@ func (p *OSTypeProber) findFromBootVolume(ctx context.Context, instanceID string
 	var volume struct {
 		ImageMetadata struct {
 			VMwareOSType string `json:"vmware_ostype"`
+			KVMOSType    string `json:"kvm_ostype"`
 		} `json:"volume_image_metadata"`
 	}
 	err = volumes.Get(ctx, p.CinderV3, rootVolumeID).ExtractInto(&volume)
 	if err != nil {
 		return "", err
 	}
 
-	for _, regex := range isValidVMwareOSTypeRegex {
+	for _, regex := range isValidOSTypeRegex {
 		if regex.MatchString(volume.ImageMetadata.VMwareOSType) {
 			return volume.ImageMetadata.VMwareOSType, nil
 		}
 	}
+	for _, regex := range isValidOSTypeRegex {
+		if regex.MatchString(volume.ImageMetadata.KVMOSType) {
+			return volume.ImageMetadata.KVMOSType, nil
+		}
+	}
 	return "unknown", nil
 }
 
 func (p *OSTypeProber) findFromImage(ctx context.Context, imageID string) (string, error) {
 	var result struct {
 		Tags         []string       `json:"tags"`
 		VMwareOSType string         `json:"vmware_ostype"`
+		KVMOSType    string         `json:"kvm_ostype"`
 		Properties   map[string]any `json:"properties"`
 	}
 	err := images.Get(ctx, p.GlanceV2, imageID).ExtractInto(&result)
@@ -182,15 +192,22 @@ func (p *OSTypeProber) findFromImage(ctx context.Context, imageID string) (strin
 	}
 
 	// prefer vmware_ostype attribute since this is validated by Nova upon booting the VM
-	for _, regex := range isValidVMwareOSTypeRegex {
+	for _, regex := range isValidOSTypeRegex {
 		if regex.MatchString(result.VMwareOSType) {
 			return result.VMwareOSType, nil
 		}
 	}
 
+	// fall back to kvm_ostype if vmware_ostype is not set
+	for _, regex := range isValidOSTypeRegex {
+		if regex.MatchString(result.KVMOSType) {
+			return result.KVMOSType, nil
+		}
+	}
+
 	// on some images, vmware_ostype values are maintained as properties.os_distro instead
 	if osDistroStr, ok := result.Properties["os_distro"].(string); ok {
-		for _, regex := range isValidVMwareOSTypeRegex {
+		for _, regex := range isValidOSTypeRegex {
 			if regex.MatchString(osDistroStr) {
 				return osDistroStr, nil
 			}