Fix overlay directory location/creation

CHANGELOG.md

@@ -59,6 +59,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fix the issue that warewulf.conf parse does not support CIDR format. #1130
 - Reduce the number of times syncuser walks the container file system. #1209
 - Create ssh key also when calling `wwctl configure --all` #1250
+- Remove the temporary overlay dir. #1180
+- Remove the temporary overlayfs dir and create them besides rootfs #1180
 
 ### Security
 
@@ -70,6 +72,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - Allow specification of the ssh-keys to be to be created. #1185
 
+### Changed
+
+- The command `wwctl container exec` locks now this container during execution. #830
+
 ### Fixed
 
 - Fix nightly release build failure issue. #1195

internal/app/wwctl/container/exec/child/main.go

@@ -34,45 +34,55 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
 		os.Exit(1)
 	}
 	conf := warewulfconf.Get()
+	runDir := container.RunDir(containerName)
+	if _, err := os.Stat(runDir); os.IsNotExist(err) {
+		return errors.Wrap(err, "container run directory does not exist")
+	}
 	mountPts := conf.MountsContainer
 	mountPts = append(container.InitMountPnts(binds), mountPts...)
 	// check for valid mount points
 	lowerObjects := checkMountPoints(containerName, mountPts)
-	overlayDir := conf.Paths.WWChrootdir + "/overlays"
 	// need to create a overlay, where the lower layer contains
 	// the missing mount points
-	wwlog.Verbose("for ephermal mount use tempdir %s", overlayDir)
-	// ignore errors as we are doomed if a tmp dir couldn't be written
-	_ = os.MkdirAll(path.Join(overlayDir, "work"), os.ModePerm)
-	_ = os.MkdirAll(path.Join(overlayDir, "lower"), os.ModePerm)
-	_ = os.MkdirAll(path.Join(overlayDir, "nodeoverlay"), os.ModePerm)
+	wwlog.Verbose("for ephermal mount use tempdir %s", runDir)
+	if err = os.Mkdir(path.Join(runDir, "work"), os.ModePerm); err != nil {
+		return err
+	}
+	if err = os.Mkdir(path.Join(runDir, "lower"), os.ModePerm); err != nil {
+		return err
+	}
+	if err = os.Mkdir(path.Join(runDir, "nodeoverlay"), os.ModePerm); err != nil {
+		return err
+	}
+	// handle all lower object, have some extra logic if the object is a file
 	for _, obj := range lowerObjects {
 		newFile := ""
 		if !strings.HasSuffix(obj, "/") {
 			newFile = filepath.Base(obj)
 			obj = filepath.Dir(obj)
 		}
-		err = os.MkdirAll(filepath.Join(overlayDir, "lower", obj), os.ModePerm)
+		err = os.Mkdir(filepath.Join(runDir, "lower", obj), os.ModePerm)
 		if err != nil {
 			wwlog.Warn("couldn't create directory for mounts: %s", err)
 		}
 		if newFile != "" {
-			desc, err := os.Create(filepath.Join(overlayDir, "lower", obj, newFile))
+			desc, err := os.Create(filepath.Join(runDir, "lower", obj, newFile))
 			if err != nil {
 				wwlog.Warn("couldn't create directory for mounts: %s", err)
 			}
 			defer desc.Close()
 		}
 	}
 	containerPath := container.RootFsDir(containerName)
+	// running in a private PID space, so also make / private, so that nothing gets out from here
 	err = syscall.Mount("", "/", "", syscall.MS_PRIVATE|syscall.MS_REC, "")
 	if err != nil {
 		return errors.Wrap(err, "failed to mount")
 	}
 	ps1Str := fmt.Sprintf("[%s] Warewulf> ", containerName)
 	if len(lowerObjects) != 0 && nodename == "" {
 		options := fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s",
-			path.Join(overlayDir, "lower"), containerPath, path.Join(overlayDir, "work"))
+			path.Join(runDir, "lower"), containerPath, path.Join(runDir, "work"))
 		wwlog.Debug("overlay options: %s", options)
 		err = syscall.Mount("overlay", containerPath, "overlay", 0, options)
 		if err != nil {
@@ -97,13 +107,13 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
 		}
 		overlays := nodes[0].SystemOverlay.GetSlice()
 		overlays = append(overlays, nodes[0].RuntimeOverlay.GetSlice()...)
-		err = overlay.BuildOverlayIndir(nodes[0], overlays, path.Join(overlayDir, "nodeoverlay"))
+		err = overlay.BuildOverlayIndir(nodes[0], overlays, path.Join(runDir, "nodeoverlay"))
 		if err != nil {
 			wwlog.Error("Could not build overlay: %s", err)
 			os.Exit(1)
 		}
 		options := fmt.Sprintf("lowerdir=%s:%s:%s",
-			path.Join(overlayDir, "lower"), containerPath, path.Join(overlayDir, "nodeoverlay"))
+			path.Join(runDir, "lower"), containerPath, path.Join(runDir, "nodeoverlay"))
 		wwlog.Debug("overlay options: %s", options)
 		err = syscall.Mount("overlay", containerPath, "overlay", 0, options)
 		if err != nil {
@@ -165,11 +175,8 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
 	os.Setenv("PATH", "/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin")
 	os.Setenv("HISTFILE", "/dev/null")
 
-	_ = syscall.Exec(args[1], args[1:], os.Environ())
-	/*
-		Exec replaces the actual program, so nothing to do here afterwards
-	*/
-	return nil
+	wwlog.Debug("Exec: %s %s", args[1], args[1:])
+	return syscall.Exec(args[1], args[1:], os.Environ())
 }
 
 /*

internal/app/wwctl/container/exec/main.go

@@ -4,13 +4,16 @@
 package exec
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"os/exec"
 	"path"
 	"syscall"
 	"time"
 
+	warewulfconf "github.com/warewulf/warewulf/internal/pkg/config"
+
 	"github.com/spf13/cobra"
 	"github.com/warewulf/warewulf/internal/pkg/container"
 	"github.com/warewulf/warewulf/internal/pkg/util"
@@ -20,23 +23,25 @@ import (
 /*
 fork off a process with a new PID space
 */
-func runContainedCmd(args []string) error {
-	var err error
-	if tempDir == "" {
-		tempDir, err = os.MkdirTemp(os.TempDir(), "overlay")
-		if err != nil {
-			wwlog.Warn("couldn't create temp dir for overlay", err)
+func runContainedCmd(args []string) (err error) {
+	conf := warewulfconf.Get()
+	containerName := args[0]
+	runDir := container.RunDir(containerName)
+	if err := os.Mkdir(runDir, 0750); err != nil {
+		if _, existerr := os.Stat(runDir); !os.IsNotExist(existerr) {
+			return errors.New("run directory already exists: another container command may already be running")
+		} else {
+			return fmt.Errorf("unable to create run directory: %w", err)
 		}
-		defer func() {
-			err = os.RemoveAll(tempDir)
-			if err != nil {
-				wwlog.Warn("Couldn't remove temp dir for ephermal mounts:", err)
-			}
-		}()
 	}
+	defer func() {
+		if err := errors.Join(os.RemoveAll(runDir), err); err != nil {
+			wwlog.Error("error removing run directory: %w", err)
+		}
+	}()
 	logStr := fmt.Sprint(wwlog.GetLogLevel())
 	wwlog.Verbose("Running contained command: %s", args[1:])
-	c := exec.Command("/proc/self/exe", append([]string{"--loglevel", logStr, "--tempdir", tempDir, "container", "exec", "__child"}, args...)...)
+	c := exec.Command("/proc/self/exe", append([]string{"--warewulfconf", conf.GetWarewulfConf(), "--loglevel", logStr, "container", "exec", "__child"}, args...)...)
 
 	c.SysProcAttr = &syscall.SysProcAttr{
 		Cloneflags: syscall.CLONE_NEWUTS | syscall.CLONE_NEWPID | syscall.CLONE_NEWNS,
@@ -45,16 +50,7 @@ func runContainedCmd(args []string) error {
 	c.Stdout = os.Stdout
 	c.Stderr = os.Stderr
 
-	if err := c.Run(); err != nil {
-		fmt.Printf("Command exited non-zero, not rebuilding/updating VNFS image\n")
-		// defer is not called before os.Exit(0)
-		err = os.RemoveAll(tempDir)
-		if err != nil {
-			wwlog.Warn("Couldn't remove temp dir for ephermal mounts:", err)
-		}
-		os.Exit(0)
-	}
-	return nil
+	return c.Run()
 }
 
 func CobraRunE(cmd *cobra.Command, args []string) error {

internal/app/wwctl/container/exec/root.go

@@ -27,15 +27,13 @@ var (
 	}
 	SyncUser bool
 	binds    []string
-	tempDir  string
 	nodeName string
 )
 
 func init() {
 	baseCmd.AddCommand(child.GetCommand())
 	baseCmd.PersistentFlags().StringArrayVarP(&binds, "bind", "b", []string{}, "Bind a local path into the container (must exist)")
 	baseCmd.PersistentFlags().BoolVar(&SyncUser, "syncuser", false, "Synchronize UIDs/GIDs from host to container")
-	baseCmd.PersistentFlags().StringVar(&tempDir, "tempdir", "", "Use tempdir for constructing the overlay fs (only used if mount points don't exist in container)")
 	baseCmd.PersistentFlags().StringVarP(&nodeName, "node", "n", "", "Create a read only view of the container for the given node")
 }
 

internal/pkg/config/root.go

@@ -42,14 +42,14 @@ type RootConf struct {
 	MountsContainer []*MountEntry `yaml:"container mounts" default:"[{\"source\": \"/etc/resolv.conf\", \"dest\": \"/etc/resolv.conf\"}]"`
 	Paths           *BuildConfig  `yaml:"paths"`
 
-	fromFile bool
+	warewulfconf string
 }
 
 // New caches and returns a new [RootConf] initialized with empty
 // values, clearing replacing any previously cached value.
 func New() *RootConf {
 	cachedConf = RootConf{}
-	cachedConf.fromFile = false
+	cachedConf.warewulfconf = ""
 	cachedConf.Warewulf = new(WarewulfConf)
 	cachedConf.DHCP = new(DHCPConf)
 	cachedConf.TFTP = new(TFTPConf)
@@ -77,12 +77,12 @@ func Get() *RootConf {
 // file.
 func (conf *RootConf) Read(confFileName string) error {
 	wwlog.Debug("Reading warewulf.conf from: %s", confFileName)
+	conf.warewulfconf = confFileName
 	if data, err := os.ReadFile(confFileName); err != nil {
 		return err
 	} else if err := conf.Parse(data); err != nil {
 		return err
 	} else {
-		conf.fromFile = true
 		return nil
 	}
 }
@@ -200,5 +200,9 @@ func (conf *RootConf) SetDynamicDefaults() (err error) {
 // InitializedFromFile returns true if [RootConf] memory was read from
 // a file, or false otherwise.
 func (conf *RootConf) InitializedFromFile() bool {
-	return conf.fromFile
+	return conf.warewulfconf != ""
+}
+
+func (conf *RootConf) GetWarewulfConf() string {
+	return conf.warewulfconf
 }

internal/pkg/config/root_test.go

@@ -67,6 +67,7 @@ func TestInitializedFromFile(t *testing.T) {
 	assert.False(t, conf.InitializedFromFile())
 	assert.NoError(t, conf.Read(tempWarewulfConf.Name()))
 	assert.True(t, conf.InitializedFromFile())
+	assert.Equal(t, conf.GetWarewulfConf(), tempWarewulfConf.Name())
 }
 
 func TestExampleRootConf(t *testing.T) {

internal/pkg/container/config.go

@@ -33,6 +33,10 @@ func RootFsDir(name string) string {
 	return path.Join(SourceDir(name), "rootfs")
 }
 
+func RunDir(name string) string {
+	return path.Join(SourceDir(name), "run")
+}
+
 func ImageParentDir() string {
 	conf := warewulfconf.Get()
 	return path.Join(conf.Paths.WWProvisiondir, "container/")