Add Kubernetes component (#110)

* Bootstrap kubernetes component

Signed-off-by: Atanas Dinov <[email protected]>

* Configure RKE2

Signed-off-by: Atanas Dinov <[email protected]>

* Remove KUBECONFIG and PATH env variables from the installer script

Signed-off-by: Atanas Dinov <[email protected]>

---------

Signed-off-by: Atanas Dinov <[email protected]>

pkg/combustion/combustion.go

@@ -84,6 +84,10 @@ func Configure(ctx *image.Context) error {
 			name:     keymapComponentName,
 			runnable: configureKeymap,
 		},
+		{
+			name:     k8sComponentName,
+			runnable: configureKubernetes,
+		},
 	}
 
 	for _, component := range combustionComponents {

pkg/combustion/kubernetes.go

@@ -0,0 +1,149 @@
+package combustion
+
+import (
+	_ "embed"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/suse-edge/edge-image-builder/pkg/fileio"
+	"github.com/suse-edge/edge-image-builder/pkg/image"
+	"github.com/suse-edge/edge-image-builder/pkg/log"
+	"github.com/suse-edge/edge-image-builder/pkg/template"
+	"go.uber.org/zap"
+)
+
+const (
+	k8sComponentName  = "kubernetes"
+	k8sConfigDir      = "kubernetes"
+	k8sConfigFile     = "config.yaml"
+	rke2InstallScript = "15-rke2-install.sh"
+)
+
+var (
+	//go:embed templates/15-rke2-installer.sh.tpl
+	rke2InstallerScript string
+)
+
+func configureKubernetes(ctx *image.Context) ([]string, error) {
+	version := ctx.ImageDefinition.Kubernetes.Version
+
+	if version == "" {
+		log.AuditComponentSkipped(k8sComponentName)
+		return nil, nil
+	}
+
+	// Show a message to the user to indicate that the Kubernetes component
+	// is usually taking longer to complete due to downloading files
+	log.Audit("Configuring Kubernetes component...")
+
+	configureFunc := kubernetesConfigurator(version)
+	if configureFunc == nil {
+		log.AuditComponentFailed(k8sComponentName)
+		return nil, fmt.Errorf("cannot configure kubernetes version: %s", version)
+	}
+
+	script, err := configureFunc(ctx)
+	if err != nil {
+		log.AuditComponentFailed(k8sComponentName)
+		return nil, fmt.Errorf("configuring kubernetes components: %w", err)
+	}
+
+	log.AuditComponentSuccessful(k8sComponentName)
+	return []string{script}, nil
+}
+
+func kubernetesConfigurator(version string) func(*image.Context) (string, error) {
+	switch {
+	case strings.Contains(version, image.KubernetesDistroRKE2):
+		return configureRKE2
+	case strings.Contains(version, image.KubernetesDistroK3S):
+		return configureK3S
+	default:
+		return nil
+	}
+}
+
+func installKubernetesScript(ctx *image.Context, distribution string) error {
+	sourcePath := "/" // root level of the container image
+	destPath := ctx.CombustionDir
+
+	return ctx.KubernetesScriptInstaller.InstallScript(distribution, sourcePath, destPath)
+}
+
+func configureK3S(_ *image.Context) (string, error) {
+	return "", fmt.Errorf("not implemented yet")
+}
+
+func configureRKE2(ctx *image.Context) (string, error) {
+	if err := installKubernetesScript(ctx, image.KubernetesDistroRKE2); err != nil {
+		return "", fmt.Errorf("copying RKE2 installer script: %w", err)
+	}
+
+	configFile, err := copyKubernetesConfig(ctx, image.KubernetesDistroRKE2)
+	if err != nil {
+		return "", fmt.Errorf("copying RKE2 config: %w", err)
+	}
+
+	installPath, imagesPath, err := ctx.KubernetesArtefactDownloader.DownloadArtefacts(
+		ctx.ImageDefinition.Kubernetes,
+		ctx.ImageDefinition.Image.Arch,
+		ctx.CombustionDir,
+	)
+	if err != nil {
+		return "", fmt.Errorf("downloading RKE2 artefacts: %w", err)
+	}
+
+	rke2 := struct {
+		image.Kubernetes
+		ConfigFile  string
+		InstallPath string
+		ImagesPath  string
+	}{
+		Kubernetes:  ctx.ImageDefinition.Kubernetes,
+		ConfigFile:  configFile,
+		InstallPath: installPath,
+		ImagesPath:  imagesPath,
+	}
+
+	data, err := template.Parse(rke2InstallScript, rke2InstallerScript, &rke2)
+	if err != nil {
+		return "", fmt.Errorf("parsing RKE2 install template: %w", err)
+	}
+
+	installScript := filepath.Join(ctx.CombustionDir, rke2InstallScript)
+	if err = os.WriteFile(installScript, []byte(data), fileio.ExecutablePerms); err != nil {
+		return "", fmt.Errorf("writing RKE2 install script: %w", err)
+	}
+
+	return rke2InstallScript, nil
+}
+
+func copyKubernetesConfig(ctx *image.Context, distro string) (string, error) {
+	if !isComponentConfigured(ctx, k8sConfigDir) {
+		zap.S().Info("Kubernetes config file not provided")
+		return "", nil
+	}
+
+	configDir := generateComponentPath(ctx, k8sConfigDir)
+	configFile := filepath.Join(configDir, k8sConfigFile)
+
+	_, err := os.Stat(configFile)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return "", fmt.Errorf("kubernetes component directory exists but does not contain config.yaml")
+		}
+		return "", fmt.Errorf("error checking kubernetes config file: %w", err)
+	}
+
+	destFile := fmt.Sprintf("%s_config.yaml", distro)
+
+	if err = fileio.CopyFile(configFile, filepath.Join(ctx.CombustionDir, destFile), fileio.NonExecutablePerms); err != nil {
+		return "", fmt.Errorf("copying kubernetes config file: %w", err)
+	}
+
+	return destFile, nil
+}