Merge pull request #4289 from twz123/keepalived

Apply some idiomatic patterns to CPLB component

Author: twz123

pkg/component/controller/cplb_unix.go

@@ -19,17 +19,18 @@ limitations under the License.
 package controller
 
 import (
+	"bufio"
 	"context"
 	"errors"
 	"fmt"
-	"io/fs"
+	"io"
 	"net"
 	"os"
 	"path/filepath"
 	"slices"
 	"text/template"
 
-	"github.com/k0sproject/k0s/internal/pkg/dir"
+	"github.com/k0sproject/k0s/internal/pkg/file"
 	"github.com/k0sproject/k0s/internal/pkg/users"
 	k0sAPI "github.com/k0sproject/k0s/pkg/apis/k0s/v1beta1"
 	"github.com/k0sproject/k0s/pkg/assets"
@@ -48,6 +49,7 @@ type Keepalived struct {
 	uid             int
 	supervisor      *supervisor.Supervisor
 	log             *logrus.Entry
+	configFilePath  string
 }
 
 // Init extracts the needed binaries and creates the directories
@@ -63,15 +65,7 @@ func (k *Keepalived) Init(_ context.Context) error {
 		k.log.Warnf("Unable to get %s UID running keepalived as root: %v", constant.KeepalivedUser, err)
 	}
 
-	basepath := filepath.Dir(k.K0sVars.KeepalivedConfigFile)
-	if err = dir.Init(basepath, constant.KeepalivedDirMode); err != nil {
-		return fmt.Errorf("failed to create keepalived data dir: %w", err)
-	}
-
-	if err = os.Chown(basepath, k.uid, -1); err != nil {
-		return fmt.Errorf("failed to chown keepalived data dir: %w", err)
-	}
-
+	k.configFilePath = filepath.Join(k.K0sVars.RunDir, "keepalived.conf")
 	return assets.Stage(k.K0sVars.BinDir, "keepalived", constant.BinDirMode)
 }
 
@@ -96,7 +90,7 @@ func (k *Keepalived) Start(_ context.Context) error {
 	args := []string{
 		"--dont-fork",
 		"--use-file",
-		k.K0sVars.KeepalivedConfigFile,
+		k.configFilePath,
 		"--no-syslog",
 		"--log-console",
 	}
@@ -110,8 +104,8 @@ func (k *Keepalived) Start(_ context.Context) error {
 		Name:    "keepalived",
 		BinPath: assets.BinPath("keepalived", k.K0sVars.BinDir),
 		Args:    args,
-		RunDir:  filepath.Dir(k.K0sVars.KeepalivedConfigFile),
-		DataDir: filepath.Dir(k.K0sVars.KeepalivedConfigFile),
+		RunDir:  k.K0sVars.RunDir,
+		DataDir: k.K0sVars.DataDir,
 		UID:     k.uid,
 	}
 	return k.supervisor.Supervise()
@@ -274,31 +268,25 @@ func (*Keepalived) getLinkAddresses(link netlink.Link) ([]netlink.Addr, []string
 }
 
 func (k *Keepalived) generateKeepalivedTemplate() error {
-	f, err := os.OpenFile(k.K0sVars.KeepalivedConfigFile, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, fs.FileMode(0500))
-	if err != nil {
-		return fmt.Errorf("failed to open keepalived config file: %w", err)
-	}
-	defer f.Close()
-
-	template, err := template.New("keepalived").Parse(keepalivedConfigTemplate)
-	if err != nil {
-		return fmt.Errorf("failed to parse keepalived template: %w", err)
-	}
-
+	template := template.Must(template.New("keepalived").Parse(keepalivedConfigTemplate))
 	kc := keepalivedConfig{
 		VRRPInstances: k.Config.VRRPInstances,
 	}
-	if err = template.Execute(f, kc); err != nil {
-		return fmt.Errorf("failed to execute keepalived template: %w", err)
-	}
 
-	// TODO: Do we really need to this every single time?
-	if err = os.Chown(k.K0sVars.KeepalivedConfigFile, k.uid, -1); err != nil {
-		return fmt.Errorf("failed to chown keepalived config file: %w", err)
-	}
-	if err = os.Chmod(k.K0sVars.KeepalivedConfigFile, fs.FileMode(0400)); err != nil {
-		return fmt.Errorf("failed to chmod keepalived config file: %w", err)
+	if err := file.WriteAtomically(k.configFilePath, 0400, func(file io.Writer) error {
+		if err := file.(*os.File).Chown(k.uid, -1); err != nil {
+			return err
+		}
+
+		w := bufio.NewWriter(file)
+		if err := template.Execute(w, kc); err != nil {
+			return err
+		}
+		return w.Flush()
+	}); err != nil {
+		return fmt.Errorf("failed to write keepalived config file: %w", err)
 	}
+
 	return nil
 }
 

pkg/config/cfgvars.go

@@ -49,7 +49,6 @@ type CfgVars struct {
 	EtcdCertDir                string // EtcdCertDir contains etcd certificates
 	EtcdDataDir                string // EtcdDataDir contains etcd state
 	KineSocketPath             string // The unix socket path for kine
-	KeepalivedConfigFile       string // location for keepalived data
 	KonnectivitySocketDir      string // location of konnectivity's socket path
 	KubeletAuthConfigPath      string // KubeletAuthConfigPath defines the default kubelet auth config path
 	KubeletVolumePluginDir     string // location for kubelet plugins volume executables
@@ -179,7 +178,6 @@ func NewCfgVars(cobraCmd command, dirs ...string) (*CfgVars, error) {
 		EtcdCertDir:                filepath.Join(certDir, "etcd"),
 		EtcdDataDir:                filepath.Join(dataDir, "etcd"),
 		KineSocketPath:             filepath.Join(runDir, constant.KineSocket),
-		KeepalivedConfigFile:       filepath.Join(dataDir, "keepalived", "keepalived.conf"),
 		KonnectivitySocketDir:      filepath.Join(runDir, "konnectivity-server"),
 		KubeletAuthConfigPath:      filepath.Join(dataDir, "kubelet.conf"),
 		KubeletVolumePluginDir:     constant.KubeletVolumePluginDir,