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Epehermal container mounts on same fs as chroot

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Previously ephemeral container mounts were performed in /tmp. Now these
mounts are overlayed on the same fs as is used for chroots.

Signed-off-by: Christian Goll <cgoll@suse.com>
This commit is contained in:
Christian Goll
2023-04-28 12:11:36 +02:00
committed by Christian Goll
parent baa8254dd5
commit d3650244f9
3 changed files with 29 additions and 39 deletions
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61
internal/app/wwctl/container/exec/child/main.go
View File

@@ -38,41 +38,30 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
mountPts = append(container.InitMountPnts(binds), mountPts...)
// check for valid mount points
lowerObjects := checkMountPoints(containerName, mountPts)
if len(lowerObjects) != 0 {
if tempDir == "" {
tempDir, err = os.MkdirTemp(os.TempDir(), "overlay")
if err != nil {
wwlog.Warn("couldn't create temp dir for overlay", err)
lowerObjects = []string{}
tempDir = ""
}
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)
for _, obj := range lowerObjects {
newFile := ""
if !strings.HasSuffix(obj, "/") {
newFile = filepath.Base(obj)
obj = filepath.Dir(obj)
}
// need to create a overlay, where the lower layer contains
// the missing mount points
if tempDir != "" {
wwlog.Verbose("for ephermal mount use tempdir %s", tempDir)
// ignore errors as we are doomed if a tmp dir couldn't be written
_ = os.Mkdir(path.Join(tempDir, "work"), os.ModePerm)
_ = os.Mkdir(path.Join(tempDir, "lower"), os.ModePerm)
_ = os.Mkdir(path.Join(tempDir, "nodeoverlay"), os.ModePerm)
for _, obj := range lowerObjects {
newFile := ""
if !strings.HasSuffix(obj, "/") {
newFile = filepath.Base(obj)
obj = filepath.Dir(obj)
}
err = os.MkdirAll(filepath.Join(tempDir, "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(tempDir, "lower", obj, newFile))
if err != nil {
wwlog.Warn("couldn't create directory for mounts: %s", err)
}
defer desc.Close()
}
err = os.MkdirAll(filepath.Join(overlayDir, "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))
if err != nil {
wwlog.Warn("couldn't create directory for mounts: %s", err)
}
defer desc.Close()
}
}
containerPath := container.RootFsDir(containerName)
@@ -83,7 +72,7 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
ps1Str := fmt.Sprintf("[%s] Warewulf> ", containerName)
if len(lowerObjects) != 0 && nodename == "" {
options := fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s",
path.Join(tempDir, "lower"), containerPath, path.Join(tempDir, "work"))
path.Join(overlayDir, "lower"), containerPath, path.Join(overlayDir, "work"))
wwlog.Debug("overlay options: %s", options)
err = syscall.Mount("overlay", containerPath, "overlay", 0, options)
if err != nil {
@@ -108,13 +97,13 @@ 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(tempDir, "nodeoverlay"))
err = overlay.BuildOverlayIndir(nodes[0], overlays, path.Join(overlayDir, "nodeoverlay"))
if err != nil {
wwlog.Error("Could not build overlay: %s", err)
os.Exit(1)
}
options := fmt.Sprintf("lowerdir=%s:%s:%s",
path.Join(tempDir, "lower"), containerPath, path.Join(tempDir, "nodeoverlay"))
path.Join(overlayDir, "lower"), containerPath, path.Join(overlayDir, "nodeoverlay"))
wwlog.Debug("overlay options: %s", options)
err = syscall.Mount("overlay", containerPath, "overlay", 0, options)
if err != nil {

6
internal/app/wwctl/container/exec/child/root.go
View File

@@ -1,6 +1,8 @@
package child
import "github.com/spf13/cobra"
import (
"github.com/spf13/cobra"
)
var (
baseCmd = &cobra.Command{
@@ -12,14 +14,12 @@ var (
FParseErrWhitelist: cobra.FParseErrWhitelist{UnknownFlags: true},
}
binds []string
tempDir string
nodename string
)
func init() {
baseCmd.Flags().StringVarP(&nodename, "node", "n", "", "create ro overlay for given node")
baseCmd.Flags().StringArrayVarP(&binds, "bind", "b", []string{}, "bind points")
baseCmd.Flags().StringVar(&tempDir, "tempdir", "", "tempdir")
}
// GetRootCommand returns the root cobra.Command for the application.