Add support for ubuntu-style dracut image names

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## v4.6.0, unreleased
 
+### Added
+
+- Support Ubuntu-style dracut initrd images.
+
 ### Fixed
 
 - Fix nightly builds.

internal/pkg/image/initramfs.go

@@ -14,6 +14,7 @@ var (
 	initramfsSearchPaths = []string{
 		"/boot/initramfs-*",
 		"/boot/initrd-*",
+		"/boot/initrd.img-*",
 	}
 
 	versionPattern *regexp.Regexp

internal/pkg/image/initramfs_test.go

@@ -20,7 +20,6 @@ func TestFindInitramfs(t *testing.T) {
 	assert.NoError(t, os.MkdirAll(filepath.Join(RootFsDir("image"), "boot"), 0700))
 
 	tests := map[string]struct {
-		name      string
 		initramfs []string
 		ver       string
 		path      string
@@ -45,6 +44,11 @@ func TestFindInitramfs(t *testing.T) {
 			ver:       "1.1.1",
 			path:      "/boot/initrd-1.1.1.aarch64.img",
 		},
+		"ok case 5 (ubuntu)": {
+			initramfs: []string{"/boot/initrd.img-6.11.0-18-generic"},
+			ver:       "6.11.0-18",
+			path:      "/boot/initrd.img-6.11.0-18-generic",
+		},
 		"prefix match": {
 			initramfs: []string{"/boot/initrd-1.1.1.aarch64.img"},
 			ver:       "1.1",