implement some basic k8s distro detection

cmd/node-installer/detect.go

@@ -0,0 +1,61 @@
+/*
+   Copyright The SpinKube Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log/slog"
+
+	"github.com/spf13/afero"
+	"github.com/spinkube/runtime-class-manager/internal/preset"
+)
+
+var containerdConfigLocations = map[string]preset.Settings{
+	// Microk8s
+	"/var/snap/microk8s/current/args/containerd-template.toml": preset.MicroK8s,
+	// RKE2
+	"/var/lib/rancher/rke2/agent/etc/containerd/config.toml": preset.RKE2,
+	// K3s
+	"/var/lib/rancher/k3s/agent/etc/containerd/config.toml": preset.K3s,
+	// default
+	"/etc/containerd/config.toml": preset.Default,
+}
+
+func DetectDistro(config Config, hostFs afero.Fs) (preset.Settings, error) {
+	if config.Runtime.ConfigPath != "" {
+		// containerd config path has been set explicitly
+		if distro, ok := containerdConfigLocations[config.Runtime.ConfigPath]; ok {
+			return distro, nil
+		}
+		slog.Warn("could not determine distro from containerd config, falling back to defaults", "config", config.Runtime.ConfigPath)
+		return preset.Default.WithConfigPath(config.Runtime.ConfigPath), nil
+	}
+
+	var errs []error
+
+	for loc, distro := range containerdConfigLocations {
+		_, err := hostFs.Stat(loc)
+		if err == nil {
+			// config file found, return corresponding distro settings
+			return distro, nil
+		}
+		errs = append(errs, err)
+	}
+
+	return preset.Settings{}, fmt.Errorf("failed to detect containerd config path: %w", errors.Join(errs...))
+}

cmd/node-installer/install.go

@@ -26,6 +26,7 @@ import (
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
 	"github.com/spinkube/runtime-class-manager/internal/containerd"
+	"github.com/spinkube/runtime-class-manager/internal/preset"
 	"github.com/spinkube/runtime-class-manager/internal/shim"
 )
 
@@ -36,9 +37,16 @@ var installCmd = &cobra.Command{
 	Run: func(_ *cobra.Command, _ []string) {
 		rootFs := afero.NewOsFs()
 		hostFs := afero.NewBasePathFs(rootFs, config.Host.RootPath)
-		restarter := containerd.NewRestarter()
 
-		if err := RunInstall(config, rootFs, hostFs, restarter); err != nil {
+		distro, err := DetectDistro(config, hostFs)
+		if err != nil {
+			slog.Error("failed to detect containerd config", "error", err)
+			os.Exit(1)
+		}
+
+		config.Runtime.ConfigPath = distro.ConfigPath
+
+		if err := RunInstall(config, rootFs, hostFs, distro.Restarter(preset.Env{ConfigPath: distro.ConfigPath, HostFs: hostFs})); err != nil {
 			slog.Error("failed to install", "error", err)
 			os.Exit(1)
 		}

cmd/node-installer/root.go

@@ -51,7 +51,7 @@ func Execute() {
 
 func init() {
 	rootCmd.PersistentFlags().StringVarP(&config.Runtime.Name, "runtime", "r", "containerd", "Set the container runtime to configure (containerd, cri-o)")
-	rootCmd.PersistentFlags().StringVarP(&config.Runtime.ConfigPath, "runtime-config", "c", "/etc/containerd/config.toml", "Path to the runtime config file")
+	rootCmd.PersistentFlags().StringVarP(&config.Runtime.ConfigPath, "runtime-config", "c", "", "Path to the runtime config file. Will try to autodetect if left empty")
 	rootCmd.PersistentFlags().StringVarP(&config.Kwasm.Path, "kwasm-path", "k", "/opt/kwasm", "Working directory for kwasm on the host")
 	rootCmd.PersistentFlags().StringVarP(&config.Host.RootPath, "host-root", "H", "/", "Path to the host root path")
 }

cmd/node-installer/uninstall.go

@@ -26,6 +26,7 @@ import (
 	"github.com/spf13/cobra"
 
 	"github.com/spinkube/runtime-class-manager/internal/containerd"
+	"github.com/spinkube/runtime-class-manager/internal/preset"
 	"github.com/spinkube/runtime-class-manager/internal/shim"
 )
 
@@ -36,9 +37,16 @@ var uninstallCmd = &cobra.Command{
 	Run: func(_ *cobra.Command, _ []string) {
 		rootFs := afero.NewOsFs()
 		hostFs := afero.NewBasePathFs(rootFs, config.Host.RootPath)
-		restarter := containerd.NewRestarter()
 
-		if err := RunUninstall(config, rootFs, hostFs, restarter); err != nil {
+		distro, err := DetectDistro(config, hostFs)
+		if err != nil {
+			slog.Error("failed to detect containerd config", "error", err)
+			os.Exit(1)
+		}
+
+		config.Runtime.ConfigPath = distro.ConfigPath
+
+		if err := RunUninstall(config, rootFs, hostFs, distro.Restarter(preset.Env{ConfigPath: distro.ConfigPath, HostFs: hostFs})); err != nil {
 			slog.Error("failed to uninstall", "error", err)
 			os.Exit(1)
 		}

internal/preset/preset.go

@@ -0,0 +1,55 @@
+package preset
+
+import (
+	"errors"
+	"os"
+
+	"github.com/spf13/afero"
+	"github.com/spinkube/runtime-class-manager/internal/containerd"
+)
+
+type Settings struct {
+	ConfigPath string
+	Setup      func(Env) error
+	Restarter  func(Env) containerd.Restarter
+}
+
+type Env struct {
+	HostFs     afero.Fs
+	ConfigPath string
+}
+
+var Default = Settings{
+	ConfigPath: "/etc/containerd/config.toml",
+	Setup:      func(_ Env) error { return nil },
+	Restarter:  func(_ Env) containerd.Restarter { return containerd.NewRestarter() },
+}
+
+func (s Settings) WithConfigPath(path string) Settings {
+	s.ConfigPath = path
+	return s
+}
+
+func (s Settings) WithSetup(setup func(env Env) error) Settings {
+	s.Setup = setup
+	return s
+}
+
+var MicroK8s = Default.WithConfigPath("/var/snap/microk8s/current/args/containerd-template.toml")
+
+var RKE2 = Default.WithConfigPath("/var/lib/rancher/rke2/agent/etc/containerd/config.toml.tmpl").
+	WithSetup(func(env Env) error {
+		_, err := env.HostFs.Stat(env.ConfigPath)
+		if err == nil {
+			return nil
+		}
+
+		if errors.Is(err, os.ErrNotExist) {
+			// TODO: Copy file from original file to new config file
+			return nil
+		}
+
+		return err
+	})
+
+var K3s = RKE2.WithConfigPath("/var/lib/rancher/k3s/agent/etc/containerd/config.toml.tmpl")