k3s/pkg/rootless/mounts.go

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// +build !windows
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package rootless
import (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"golang.org/x/sys/unix"
)
func setupMounts(stateDir string) error {
// Remove symlinks to the rootful files, so that we can create our own files.
removeList := []string{
"/var/run/netns",
"/run/containerd",
"/run/xtables.lock",
}
for _, f := range removeList {
_ = os.RemoveAll(f)
}
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mountMap := [][]string{
{"/var/log", filepath.Join(stateDir, "logs")},
{"/var/lib/cni", filepath.Join(stateDir, "cni")},
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{"/var/lib/kubelet", filepath.Join(stateDir, "kubelet")},
{"/etc/rancher", filepath.Join(stateDir, "etc", "rancher")},
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}
for _, v := range mountMap {
if err := setupMount(v[0], v[1]); err != nil {
return errors.Wrapf(err, "failed to setup mount %s => %s", v[0], v[1])
}
}
if devKmsg, err := os.Open("/dev/kmsg"); err == nil {
devKmsg.Close()
} else {
// kubelet requires /dev/kmsg to be readable
// https://github.com/rootless-containers/usernetes/issues/204
// https://github.com/rootless-containers/usernetes/pull/214
logrus.Debugf("`kernel.dmesg_restrict` seems to be set, bind-mounting /dev/null into /dev/kmsg")
if err := unix.Mount("/dev/null", "/dev/kmsg", "none", unix.MS_BIND, ""); err != nil {
return err
}
}
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return nil
}
func setupMount(target, dir string) error {
toCreate := target
for {
if toCreate == "/" {
return fmt.Errorf("missing /%s on the root filesystem", strings.Split(target, "/")[0])
}
if err := os.MkdirAll(toCreate, 0700); err == nil {
break
}
toCreate = filepath.Base(toCreate)
}
if err := os.MkdirAll(toCreate, 0700); err != nil {
return errors.Wrapf(err, "failed to create directory %s", toCreate)
}
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logrus.Debug("Mounting none ", toCreate, " tmpfs")
if err := unix.Mount("none", toCreate, "tmpfs", 0, ""); err != nil {
return errors.Wrapf(err, "failed to mount tmpfs to %s", toCreate)
}
if err := os.MkdirAll(target, 0700); err != nil {
return errors.Wrapf(err, "failed to create directory %s", target)
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}
if dir == "" {
return nil
}
if err := os.MkdirAll(dir, 0700); err != nil {
return errors.Wrapf(err, "failed to create directory %s", dir)
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}
logrus.Debug("Mounting ", dir, target, " none bind")
return unix.Mount(dir, target, "none", unix.MS_BIND, "")
}