Stock ignition configuration

internal/build/build.go

@@ -21,6 +21,7 @@ package build
 import (
 	"context"
 	"fmt"
+	"path/filepath"
 	"strings"
 
 	"github.com/suse/elemental/v3/internal/config"
@@ -141,7 +142,12 @@ func newDeployment(
 			return nil, fmt.Errorf("computing configuration partition size: %w", err)
 		}
 
-		deploymentOpts = append(deploymentOpts, deployment.WithConfigPartition(deployment.MiB(configSize)))
+		configLabel := deployment.CatalystLabel
+		if ignDir, _ := vfs.Exists(system.FS(), filepath.Join(output.FirstbootConfigDir(), image.IgnitionFilePath())); ignDir {
+			configLabel = deployment.IgnitionLabel
+		}
+
+		deploymentOpts = append(deploymentOpts, deployment.WithConfigPartition(deployment.MiB(configSize), configLabel))
 	}
 
 	d := deployment.New(deploymentOpts...)

internal/cli/action/customize.go

@@ -123,12 +123,12 @@ func setupCustomizeRunner(
 
 	return &customize.Runner{
 		System:        s,
-		ConfigManager: setupConfigManager(s, args.ConfigDir, output, args.Local),
+		ConfigManager: setupConfigManager(s, args.ConfigDir, output, args.BaseConfig, args.Local),
 		FileExtractor: extr,
 	}, nil
 }
 
-func setupConfigManager(s *sys.System, configDir string, output config.Output, local bool) *config.Manager {
+func setupConfigManager(s *sys.System, configDir string, output config.Output, baseConfig, local bool) *config.Manager {
 	valuesResolver := &helm.ValuesResolver{
 		FS:        s.FS(),
 		ValuesDir: v0.Dir(configDir).HelmValuesDir(),
@@ -139,6 +139,7 @@ func setupConfigManager(s *sys.System, configDir string, output config.Output, l
 		config.NewHelm(s.FS(), valuesResolver, s.Logger(), output.OverlaysDir()),
 		config.WithDownloadFunc(http.DownloadFile),
 		config.WithLocal(local),
+		config.WithBaseConfig(baseConfig),
 	)
 }
 

internal/cli/cmd/customize.go

@@ -34,6 +34,7 @@ type CustomizeFlags struct {
 	Platform   string
 	MediaType  string
 	Local      bool
+	BaseConfig bool
 }
 
 var CustomizeArgs CustomizeFlags
@@ -90,6 +91,11 @@ func NewCustomizeCommand(appName string, action func(context.Context, *cli.Comma
 				Usage:       localDesc,
 				Destination: &CustomizeArgs.Local,
 			},
+			&cli.BoolFlag{
+				Name:        "base-config",
+				Usage:       "Sets the Ignition configuration to be included as the base configuration",
+				Destination: &CustomizeArgs.BaseConfig,
+			},
 		},
 	}
 }

internal/config/config.go

@@ -98,6 +98,10 @@ func (o Output) ISOStoreDir() string {
 	return filepath.Join(o.ExtractedFilesStoreDir(), "ISOs")
 }
 
+func (o Output) InitrdExtensionFile() string {
+	return filepath.Join(o.RootPath, "initrdExt.cpio")
+}
+
 func (o Output) Cleanup(fs vfs.FS) error {
 	return fs.RemoveAll(o.RootPath)
 }

internal/config/config_test.go

@@ -18,6 +18,8 @@ limitations under the License.
 package config_test
 
 import (
+	"path/filepath"
+
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 
@@ -26,6 +28,13 @@ import (
 	sysmock "github.com/suse/elemental/v3/pkg/sys/mock"
 )
 
+var _ = Describe("Output", func() {
+	It("InitrdExtensionFile returns the CPIO path relative to RootPath", func() {
+		output := config.Output{RootPath: "/my/root"}
+		Expect(output.InitrdExtensionFile()).To(Equal(filepath.Join("/my/root", "initrdExt.cpio")))
+	})
+})
+
 var _ = Describe("Schema", func() {
 
 	It("Successfully loads a schema version", func() {

internal/config/ignition.go

@@ -18,6 +18,7 @@ limitations under the License.
 package config
 
 import (
+	"context"
 	_ "embed"
 	"fmt"
 	"path/filepath"
@@ -27,12 +28,14 @@ import (
 	"go.yaml.in/yaml/v3"
 
 	"github.com/suse/elemental/v3/internal/butane"
+	"github.com/suse/elemental/v3/internal/cpio"
 	"github.com/suse/elemental/v3/internal/image"
 	"github.com/suse/elemental/v3/internal/image/kubernetes"
 	"github.com/suse/elemental/v3/internal/template"
 	"github.com/suse/elemental/v3/pkg/extensions"
 	"github.com/suse/elemental/v3/pkg/manifest/api"
 	"github.com/suse/elemental/v3/pkg/sys"
+	"github.com/suse/elemental/v3/pkg/sys/vfs"
 )
 
 const (
@@ -41,6 +44,8 @@ const (
 	updateLinkerCacheUnitName   = "update-linker-cache.service"
 	k8sResourcesUnitName        = "k8s-resource-installer.service"
 	k8sConfigUnitName           = "k8s-config-installer.service"
+	ignitionFileName            = "10-elemental.ign"
+	ignitionFromButaneFileName  = "90-butane.ign"
 )
 
 var (
@@ -68,6 +73,9 @@ var (
 // * Kubernetes configuration and deployment files
 // * Systemd extensions
 // * Kubernetes distribution installation
+//
+// if baseConfig is set to true it builds a CPIO file containing the Ignition configuration at /usr/lib/ignition/base.d
+// the CPIO file can be used as an initrd extension allowing the user to provide user configuration that is merged on top.
 func (m *Manager) configureIgnition(conf *image.Configuration, output Output, k8sScript, k8sConfScript string, ext []api.SystemdExtension) error {
 	if len(conf.ButaneConfig) == 0 &&
 		k8sScript == "" &&
@@ -86,18 +94,6 @@ func (m *Manager) configureIgnition(conf *image.Configuration, output Output, k8
 	config.Variant = variant
 	config.Version = version
 
-	if len(conf.ButaneConfig) > 0 {
-		m.system.Logger().Info("Translating butane configuration to Ignition syntax")
-
-		ignitionBytes, err := butane.TranslateBytes(m.system, conf.ButaneConfig)
-		if err != nil {
-			return fmt.Errorf("failed translating butane configuration: %w", err)
-		}
-		config.MergeInlineIgnition(string(ignitionBytes))
-	} else {
-		m.system.Logger().Info("No butane configuration to translate into Ignition syntax")
-	}
-
 	if k8sScript != "" {
 		initHostname := "*"
 		if len(conf.Kubernetes.Nodes) > 0 {
@@ -142,10 +138,65 @@ func (m *Manager) configureIgnition(conf *image.Configuration, output Output, k8
 		config.AddSystemdUnit(updateLinkerCacheUnitName, updateLinkerCacheUnit, true)
 	}
 
+	if m.baseConfig {
+		return m.writeBaseIgnitionConfig(output, config, conf.ButaneConfig)
+	}
+
+	return m.writeUserIgnitionConfig(output, config, conf.ButaneConfig)
+}
+
+// writeUserIgnitionConfig renders the Ignition configuration including the provided butane configuration as a single
+// <ignition_device>/ignition/config.ign file. From Ignition's PoV this represents the user configuration which gets merged
+// with the stock configuration, if any.
+func (m *Manager) writeUserIgnitionConfig(output Output, config butane.Config, butaneConfing map[string]any) error {
+	if len(butaneConfing) > 0 {
+		m.system.Logger().Info("Translating butane configuration to Ignition syntax")
+
+		ignitionBytes, err := butane.TranslateBytes(m.system, butaneConfing)
+		if err != nil {
+			return fmt.Errorf("failed translating butane configuration: %w", err)
+		}
+		config.MergeInlineIgnition(string(ignitionBytes))
+	}
+
 	ignitionFile := filepath.Join(output.FirstbootConfigDir(), image.IgnitionFilePath())
 	return butane.WriteIgnitionFile(m.system, config, ignitionFile)
 }
 
+// writeBaseIgnitionConfig renders the generated Ignition configuration including the user provided butane configuration
+// as part of a CPIO file, which can be used to extend the OS initrd and include ignition base configuration the expected
+// /usr/lib/ignition/base.d path
+func (m *Manager) writeBaseIgnitionConfig(output Output, config butane.Config, butaneConfing map[string]any) (err error) {
+	tmpDir, err := vfs.TempDir(m.system.FS(), output.RootPath, "initrd")
+	if err != nil {
+		return fmt.Errorf("creating temporary directory for ignition initrd extension: %w", err)
+	}
+	defer func() {
+		e := m.system.FS().RemoveAll(tmpDir)
+		if err == nil && e != nil {
+			err = e
+		}
+	}()
+
+	ignitionFile := filepath.Join(tmpDir, image.IgnitionBaseConfigPath(), ignitionFileName)
+	err = butane.WriteIgnitionFile(m.system, config, ignitionFile)
+	if err != nil {
+		return fmt.Errorf("writing ignition file %q: %w", ignitionFile, err)
+	}
+
+	if len(butaneConfing) > 0 {
+		m.system.Logger().Info("Translating butane configuration to Ignition syntax")
+
+		butaneFile := filepath.Join(tmpDir, image.IgnitionBaseConfigPath(), ignitionFromButaneFileName)
+		err = butane.WriteIgnitionFile(m.system, butaneConfing, butaneFile)
+		if err != nil {
+			return fmt.Errorf("writing ignition file %q: %w", butaneFile, err)
+		}
+	}
+
+	return cpio.CreateCPIO(context.Background(), m.system, tmpDir, output.InitrdExtensionFile())
+}
+
 func generateK8sResourcesUnit(deployScript, initHostname string) (string, error) {
 	values := struct {
 		KubernetesDir        string

internal/config/ignition_test.go

@@ -218,4 +218,59 @@ passwd:
 		Expect(ignition).To(ContainSubstring("merge"))
 		Expect(buffer.String()).To(ContainSubstring("translating Butane to Ignition reported non-fatal entries"))
 	})
+
+	Describe("Ignition configuration as base config", func() {
+		BeforeEach(func() {
+			m = NewManager(system, nil, WithBaseConfig(true))
+		})
+
+		It("Creates a CPIO initrd extension instead of a firstboot ignition file", func() {
+			conf := &image.Configuration{
+				Kubernetes: kubernetes.Kubernetes{
+					Config: kubernetes.Config{
+						RegistriesFilePath: "/etc/kubernetes/config/registries.yaml",
+					},
+				},
+			}
+
+			Expect(m.configureIgnition(conf, output, "", "k8sConfScript", nil)).To(Succeed())
+
+			ok, _ := vfs.Exists(system.FS(), filepath.Join(output.FirstbootConfigDir(), image.IgnitionFilePath()))
+			Expect(ok).To(BeFalse())
+
+			ok, _ = vfs.Exists(system.FS(), output.InitrdExtensionFile())
+			Expect(ok).To(BeTrue())
+
+			cpioContent, err := system.FS().ReadFile(output.InitrdExtensionFile())
+			Expect(err).NotTo(HaveOccurred())
+			Expect(string(cpioContent)).To(ContainSubstring(ignitionFileName))
+			Expect(string(cpioContent)).NotTo(ContainSubstring(ignitionFromButaneFileName))
+		})
+
+		It("Creates a CPIO with both elemental and butane ignition files when ButaneConfig is provided", func() {
+			var butaneConf map[string]any
+
+			butaneConfigString := `
+version: 1.6.0
+variant: fcos
+passwd:
+  users:
+  - name: pipo
+    password_hash: $y$j9T$aUmgEDoFIDPhGxEe2FUjc/$C5A...
+`
+			Expect(v0.ParseAny([]byte(butaneConfigString), &butaneConf)).To(Succeed())
+			conf := &image.Configuration{ButaneConfig: butaneConf}
+
+			Expect(m.configureIgnition(conf, output, "", "", nil)).To(Succeed())
+
+			ok, err := vfs.Exists(system.FS(), filepath.Join(output.FirstbootConfigDir(), image.IgnitionFilePath()))
+			Expect(err).NotTo(HaveOccurred())
+			Expect(ok).To(BeFalse())
+
+			cpioContent, err := system.FS().ReadFile(output.InitrdExtensionFile())
+			Expect(err).NotTo(HaveOccurred())
+			Expect(string(cpioContent)).To(ContainSubstring(ignitionFileName))
+			Expect(string(cpioContent)).To(ContainSubstring(ignitionFromButaneFileName))
+		})
+	})
 })

internal/config/manager.go

@@ -47,6 +47,10 @@ type Manager struct {
 	system *sys.System
 	local  bool
 
+	// baseConfig sets Ignition configuration to be included as base configuration
+	// allowing a user configuration to be merged on top
+	baseConfig bool
+
 	rmResolver   releaseManifestResolver
 	downloadFile downloadFunc
 	unpackImage  unpackFunc
@@ -79,6 +83,12 @@ func WithLocal(local bool) Opts {
 	}
 }
 
+func WithBaseConfig(baseConfig bool) Opts {
+	return func(m *Manager) {
+		m.baseConfig = baseConfig
+	}
+}
+
 func NewManager(sys *sys.System, helm helmConfigurator, opts ...Opts) *Manager {
 	m := &Manager{
 		system: sys,