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- added option which allows to copy in file on wwctl container exec

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and keep them, if they were modified
- added added-cow-option-to-bind.patch

OBS-URL: https://build.opensuse.org/package/show/network:cluster/warewulf4?expand=0&rev=88
This commit is contained in:
Christian Goll 2024-08-22 13:18:52 +00:00 committed by Git OBS Bridge
parent 338608dd84
commit 46a58cd5a0
3 changed files with 233 additions and 0 deletions
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225
added-cow-option-to-bind.patch Normal file
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@ -0,0 +1,225 @@
diff --git a/internal/app/wwctl/container/exec/child/main.go b/internal/app/wwctl/container/exec/child/main.go
index 253a6ad2..ba9ad9f7 100644
--- a/internal/app/wwctl/container/exec/child/main.go
+++ b/internal/app/wwctl/container/exec/child/main.go
@@ -92,7 +92,7 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
wwlog.Debug("overlay options: %s", options)
err = syscall.Mount("overlay", containerPath, "overlay", 0, options)
if err != nil {
- wwlog.Warn(fmt.Sprintf("Couldn't create overlay for ephermal mount points: %s", err))
+ wwlog.Warn("Couldn't create overlay for ephermal mount points: %s", err)
}
} else if nodename != "" {
nodeDB, err := node.New()
@@ -142,6 +142,10 @@ func CobraRunE(cmd *cobra.Command, args []string) (err error) {
}
for _, mntPnt := range mountPts {
+ if mntPnt.Cow {
+ continue
+ }
+ wwlog.Debug("bind mounting: %s -> %s", mntPnt.Source, path.Join(containerPath, mntPnt.Dest))
err = syscall.Mount(mntPnt.Source, path.Join(containerPath, mntPnt.Dest), "", syscall.MS_BIND, "")
if err != nil {
wwlog.Warn("Couldn't mount %s to %s: %s", mntPnt.Source, mntPnt.Dest, err)
@@ -195,6 +199,9 @@ the invalid mount points. Directories always have '/' as suffix
func checkMountPoints(containerName string, binds []*warewulfconf.MountEntry) (overlayObjects []string) {
overlayObjects = []string{}
for _, b := range binds {
+ if b.Cow {
+ continue
+ }
_, err := os.Stat(b.Source)
if err != nil {
wwlog.Debug("Couldn't stat %s create no mount point in container", b.Source)
diff --git a/internal/app/wwctl/container/exec/main.go b/internal/app/wwctl/container/exec/main.go
index 60cf9d48..788adc86 100644
--- a/internal/app/wwctl/container/exec/main.go
+++ b/internal/app/wwctl/container/exec/main.go
@@ -54,7 +54,6 @@ func runContainedCmd(cmd *cobra.Command, containerName string, args []string) (e
}()
logStr := fmt.Sprint(wwlog.GetLogLevel())
-
childArgs := []string{"--warewulfconf", conf.GetWarewulfConf(), "--loglevel", logStr, "container", "exec", "__child"}
childArgs = append(childArgs, containerName)
for _, b := range binds {
@@ -64,8 +63,40 @@ func runContainedCmd(cmd *cobra.Command, containerName string, args []string) (e
childArgs = append(childArgs, "--node", nodeName)
}
childArgs = append(childArgs, args...)
+ // copy the files into the container at this stage, es in __child the
+ // command syscall.Exec which replaces the __child process with the
+ // exec command in the container. All the mounts, have to be done in
+ // __child so that the used mounts don't propagate outside on the host
+ // (see the CLONE attributes), but as for the cow copy option we need
+ // to see if a file was modified after it was copied into the container
+ // so do this here.
+ // At first read out conf, the parse commandline, as copy files has the
+ // same synatx as mount points
+ mountPts := conf.MountsContainer
+ mountPts = append(container.InitMountPnts(binds), mountPts...)
+ filesToCpy := getCopyFiles(containerName, mountPts)
+ for i, cpyFile := range filesToCpy {
+ if err = util.CopyFile(cpyFile.Src, path.Join(container.RootFsDir(containerName), cpyFile.FileName)); err != nil {
+ return fmt.Errorf("couldn't copy files into container: %w", err)
+ }
+ // we can ignore error as the file was copied
+ stat, _ := os.Stat(path.Join(container.RootFsDir(containerName), cpyFile.FileName))
+ filesToCpy[i].ModTime = stat.ModTime()
+ }
wwlog.Verbose("Running contained command: %s", childArgs)
- return childCommandFunc(cmd, childArgs)
+ retVal := childCommandFunc(cmd, childArgs)
+ for _, cpyFile := range filesToCpy {
+ if modStat, err := os.Stat(path.Join(container.RootFsDir(containerName), cpyFile.FileName)); err != nil {
+ wwlog.Warn("copied file was removed: %s", err)
+ } else {
+ if modStat.ModTime() == cpyFile.ModTime {
+ if err := os.Remove(path.Join(container.RootFsDir(containerName), cpyFile.FileName)); err != nil {
+ wwlog.Warn("couldn't remove copied file: %s", err)
+ }
+ }
+ }
+ }
+ return retVal
}
func CobraRunE(cmd *cobra.Command, args []string) error {
@@ -154,3 +185,40 @@ func SetBinds(myBinds []string) {
func SetNode(myNode string) {
nodeName = myNode
}
+
+// file name and last modification time so we can remove the file if it wasn't modified
+type cowFile struct {
+ FileName string
+ Src string
+ ModTime time.Time
+ Cow bool
+}
+
+/*
+Check the objects we want to copy in, instead of mounting
+*/
+func getCopyFiles(containerNamer string, binds []*warewulfconf.MountEntry) (copyObjects []cowFile) {
+ for _, bind := range binds {
+ if !bind.Cow || bind.ReadOnly {
+ continue
+ }
+ if _, err := os.Stat(path.Join(container.RootFsDir(containerNamer), path.Dir(bind.Dest))); err != nil {
+ wwlog.Warn("destination directory doesn't exist: %s", err)
+ continue
+ }
+ if _, err := os.Stat(path.Join(container.RootFsDir(containerNamer), bind.Dest)); err == nil {
+ wwlog.Verbose("file exists in container: %s", bind.Dest)
+ continue
+ }
+ if _, err := os.Stat(bind.Source); err != nil {
+ wwlog.Warn("source doesn't exist: %s", err)
+ continue
+ }
+ copyObjects = append(copyObjects, cowFile{
+ FileName: bind.Dest,
+ Src: bind.Source,
+ Cow: bind.Cow,
+ })
+ }
+ return
+}
diff --git a/internal/app/wwctl/container/exec/root.go b/internal/app/wwctl/container/exec/root.go
index 4b74c941..0b6aaf63 100644
--- a/internal/app/wwctl/container/exec/root.go
+++ b/internal/app/wwctl/container/exec/root.go
@@ -32,7 +32,11 @@ var (
func init() {
baseCmd.AddCommand(child.GetCommand())
- baseCmd.PersistentFlags().StringArrayVarP(&binds, "bind", "b", []string{}, "Bind a local path into the container (must exist)")
+ baseCmd.PersistentFlags().StringArrayVarP(&binds, "bind", "b", []string{}, `Bind a local path which must exist into the container. Syntax is
+source[:destination[:{ro|cow}]] If destination is not set,
+it will the same path as source.The additional parameter is
+ro for read only and cow, which means the file is copied into
+the container and removed if not modified.`)
baseCmd.PersistentFlags().BoolVar(&SyncUser, "syncuser", false, "Synchronize UIDs/GIDs from host to container")
baseCmd.PersistentFlags().StringVarP(&nodeName, "node", "n", "", "Create a read only view of the container for the given node")
}
diff --git a/internal/app/wwctl/container/shell/root.go b/internal/app/wwctl/container/shell/root.go
index cceb7512..52d9825d 100644
--- a/internal/app/wwctl/container/shell/root.go
+++ b/internal/app/wwctl/container/shell/root.go
@@ -28,7 +28,11 @@ var (
)
func init() {
- baseCmd.PersistentFlags().StringArrayVarP(&binds, "bind", "b", []string{}, "Bind a local path into the container (must exist)")
+ baseCmd.PersistentFlags().StringArrayVarP(&binds, "bind", "b", []string{}, `Bind a local path which must exist into the container. Syntax is
+source[:destination[:{ro|cow}]] If destination is not set,
+it will the same path as source.The additional parameter is
+ro for read only and cow, which means the file is copied into
+the container and removed if not modified.`)
baseCmd.PersistentFlags().StringVarP(&nodeName, "node", "n", "", "Create a read only view of the container for the given node")
}
diff --git a/internal/pkg/config/mounts.go b/internal/pkg/config/mounts.go
index 2eb5060b..35805202 100644
--- a/internal/pkg/config/mounts.go
+++ b/internal/pkg/config/mounts.go
@@ -7,4 +7,5 @@ type MountEntry struct {
Dest string `yaml:"dest,omitempty"`
ReadOnly bool `yaml:"readonly,omitempty"`
Options string `yaml:"options,omitempty"` // ignored at the moment
+ Cow bool `yaml:"cow,omitempty"` // copy the file into the container and don't remove if modified
}
diff --git a/internal/pkg/container/mountpoints.go b/internal/pkg/container/mountpoints.go
index 5de00c75..7c16a0a9 100644
--- a/internal/pkg/container/mountpoints.go
+++ b/internal/pkg/container/mountpoints.go
@@ -21,13 +21,19 @@ func InitMountPnts(binds []string) (mounts []*warewulfconf.MountEntry) {
dest = bind[1]
}
readonly := false
- if len(bind) >= 3 && bind[2] == "ro" {
- readonly = true
+ cow := false
+ if len(bind) >= 3 {
+ if bind[2] == "ro" {
+ readonly = true
+ } else if bind[2] == "cow" {
+ cow = true
+ }
}
mntPnt := warewulfconf.MountEntry{
Source: bind[0],
Dest: dest,
ReadOnly: readonly,
+ Cow: cow,
}
mounts = append(mounts, &mntPnt)
}
diff --git a/userdocs/contents/containers.rst b/userdocs/contents/containers.rst
index aa8385eb..02e0fbc6 100644
--- a/userdocs/contents/containers.rst
+++ b/userdocs/contents/containers.rst
@@ -216,6 +216,21 @@ when using the exec command. This works as follows:
location, as it is almost always present and empty in every Linux
distribution (as prescribed by the LSB file hierarchy standard).
+Files which should always be present in a container image like ``resolv.conf``
+can be specified in ``warewulf.conf`` with following container_exit
+
+.. code-block:: yaml
+ container mounts:
+ - source: /etc/resolv.conf
+ dest: /etc/resolv.conf
+ readonly: true
+
+.. note::
+ Instead of the ``readonly`` setting you can set ``cow``, which
+ has the effect, that the source file is copied to the container
+ and removed if it was modified. This useful for file used for
+ registrations.
+
When the command completes, if anything within the container changed,
the container will be rebuilt into a bootable static object
automatically.

7
warewulf4.changes
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@ -1,3 +1,10 @@
-------------------------------------------------------------------
Thu Aug 22 12:56:41 UTC 2024 - Christian Goll <cgoll@suse.com>
- added option which allows to copy in file on wwctl container exec
and keep them, if they were modified
- added added-cow-option-to-bind.patch
-------------------------------------------------------------------
Fri Aug 09 12:39:33 UTC 2024 - cgoll@suse.com

1
warewulf4.spec
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@ -35,6 +35,7 @@ Source5: warewulf4-rpmlintrc
Source10: config-ww4.sh
Source11: adjust_overlays.sh
Source20: README.dnsmasq
Patch0: added-cow-option-to-bind.patch
# no firewalld in sle12
%if 0%{?sle_version} >= 150000 || 0%{?suse_version} > 1500