daemon: remove handling for deprecated "oom-score-adjust", and produce error

This option was deprecated in 5a922dc162bbe0a03450165da4e6aceca55073d4, which
is part of the v24.0.0 release, so we can remove it from master.

This patch;

- adds a check to ValidatePlatformConfig, and produces a fatal error
  if oom-score-adjust is set
- removes the deprecated libcontainerd/supervisor.WithOOMScore
- removes the warning from docker info

With this patch:

    dockerd --oom-score-adjust=-500 --validate
    Flag --oom-score-adjust has been deprecated, and will be removed in the next release.
    unable to configure the Docker daemon with file /etc/docker/daemon.json: merged configuration validation from file and command line flags failed: DEPRECATED: The "oom-score-adjust" config parameter and the dockerd "--oom-score-adjust" options have been removed.

And when using `daemon.json`:

    dockerd --validate
    unable to configure the Docker daemon with file /etc/docker/daemon.json: merged configuration validation from file and command line flags failed: DEPRECATED: The "oom-score-adjust" config parameter and the dockerd "--oom-score-adjust" options have been removed.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cmd/dockerd/config_unix.go

@@ -46,6 +46,7 @@ func installConfigFlags(conf *config.Config, flags *pflag.FlagSet) error {
 	flags.StringVar(&conf.CgroupParent, "cgroup-parent", "", "Set parent cgroup for all containers")
 	flags.StringVar(&conf.RemappedRoot, "userns-remap", "", "User/Group setting for user namespaces")
 	flags.BoolVar(&conf.LiveRestoreEnabled, "live-restore", false, "Enable live restore of docker when containers are still running")
+	// TODO(thaJeztah): Used to produce a deprecation error; remove the flag and the OOMScoreAdjust field for the next release after v25.0.0.
 	flags.IntVar(&conf.OOMScoreAdjust, "oom-score-adjust", 0, "Set the oom_score_adj for the daemon (deprecated)")
 	_ = flags.MarkDeprecated("oom-score-adjust", "and will be removed in the next release.")
 	flags.BoolVar(&conf.Init, "init", false, "Run an init in the container to forward signals and reap processes")

cmd/dockerd/daemon.go

@@ -629,11 +629,7 @@ func initMiddlewares(s *apiserver.Server, cfg *config.Config, pluginStore plugin
 }
 
 func (cli *DaemonCli) getContainerdDaemonOpts() ([]supervisor.DaemonOpt, error) {
-	opts, err := cli.getPlatformContainerdDaemonOpts()
-	if err != nil {
-		return nil, err
-	}
-
+	var opts []supervisor.DaemonOpt
 	if cli.Debug {
 		opts = append(opts, supervisor.WithLogLevel("debug"))
 	} else {

cmd/dockerd/daemon_unix.go

@@ -56,19 +56,6 @@ func setDefaultUmask() error {
 	return nil
 }
 
-func (cli *DaemonCli) getPlatformContainerdDaemonOpts() ([]supervisor.DaemonOpt, error) {
-	opts := []supervisor.DaemonOpt{
-		// TODO(thaJeztah) change this to use /proc/self/oom_score_adj instead,
-		// which would allow us to set the correct score even if dockerd's score
-		// was set through other means (such as systemd or "manually").
-		supervisor.WithOOMScore(cli.Config.OOMScoreAdjust), //nolint:staticcheck // ignore SA1019 (WithOOMScore is deprecated); will be removed in the next release.
-	}
-	if cli.Config.OOMScoreAdjust != 0 {
-		logrus.Warn(`DEPRECATED: The "oom-score-adjust" config parameter and the dockerd "--oom-score-adjust" option will be removed in the next release.`)
-	}
-	return opts, nil
-}
-
 // setupConfigReloadTrap configures the SIGHUP signal to reload the configuration.
 func (cli *DaemonCli) setupConfigReloadTrap() {
 	c := make(chan os.Signal, 1)

cmd/dockerd/daemon_windows.go

@@ -7,7 +7,6 @@ import (
 	"time"
 
 	"github.com/docker/docker/daemon/config"
-	"github.com/docker/docker/libcontainerd/supervisor"
 	"github.com/docker/docker/pkg/system"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/sys/windows"
@@ -52,10 +51,6 @@ func notifyShutdown(err error) {
 	}
 }
 
-func (cli *DaemonCli) getPlatformContainerdDaemonOpts() ([]supervisor.DaemonOpt, error) {
-	return nil, nil
-}
-
 // setupConfigReloadTrap configures a Win32 event to reload the configuration.
 func (cli *DaemonCli) setupConfigReloadTrap() {
 	go func() {

daemon/config/config_linux.go

@@ -184,6 +184,9 @@ func verifyDefaultCgroupNsMode(mode string) error {
 
 // ValidatePlatformConfig checks if any platform-specific configuration settings are invalid.
 func (conf *Config) ValidatePlatformConfig() error {
+	if conf.OOMScoreAdjust != 0 {
+		return errors.New(`DEPRECATED: The "oom-score-adjust" config parameter and the dockerd "--oom-score-adjust" options have been removed.`)
+	}
 	if err := verifyDefaultIpcMode(conf.IpcMode); err != nil {
 		return err
 	}

daemon/daemon.go

@@ -767,8 +767,8 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S
 		return nil, err
 	}
 	rootIDs := idMapping.RootPair()
-	if err := setupDaemonProcess(config); err != nil {
-		return nil, err
+	if err := setMayDetachMounts(); err != nil {
+		logrus.WithError(err).Warn("Could not set may_detach_mounts kernel parameter")
 	}
 
 	// set up the tmpDir to use a canonical path

daemon/daemon_unix.go

@@ -1415,18 +1415,6 @@ func (daemon *Daemon) setDefaultIsolation() error {
 	return nil
 }
 
-// setupDaemonProcess sets various settings for the daemon's process
-func setupDaemonProcess(config *config.Config) error {
-	// setup the daemons oom_score_adj
-	if err := setupOOMScoreAdj(config.OOMScoreAdjust); err != nil {
-		return err
-	}
-	if err := setMayDetachMounts(); err != nil {
-		logrus.WithError(err).Warn("Could not set may_detach_mounts kernel parameter")
-	}
-	return nil
-}
-
 // This is used to allow removal of mountpoints that may be mounted in other
 // namespaces on RHEL based kernels starting from RHEL 7.4.
 // Without this setting, removals on these RHEL based kernels may fail with
@@ -1456,30 +1444,6 @@ func setMayDetachMounts() error {
 	return err
 }
 
-func setupOOMScoreAdj(score int) error {
-	if score == 0 {
-		return nil
-	}
-	f, err := os.OpenFile("/proc/self/oom_score_adj", os.O_WRONLY, 0)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-	stringScore := strconv.Itoa(score)
-	_, err = f.WriteString(stringScore)
-	if os.IsPermission(err) {
-		// Setting oom_score_adj does not work in an
-		// unprivileged container. Ignore the error, but log
-		// it if we appear not to be in that situation.
-		if !userns.RunningInUserNS() {
-			logrus.Debugf("Permission denied writing %q to /proc/self/oom_score_adj", stringScore)
-		}
-		return nil
-	}
-
-	return err
-}
-
 func (daemon *Daemon) initCPURtController(mnt, path string) error {
 	if path == "/" || path == "." {
 		return nil

daemon/daemon_windows.go

@@ -548,7 +548,7 @@ func (daemon *Daemon) setDefaultIsolation() error {
 	return nil
 }
 
-func setupDaemonProcess(config *config.Config) error {
+func setMayDetachMounts() error {
 	return nil
 }
 

daemon/info_unix.go

@@ -164,9 +164,6 @@ func (daemon *Daemon) fillPlatformInfo(v *types.Info, sysInfo *sysinfo.SysInfo)
 	if !v.BridgeNfIP6tables {
 		v.Warnings = append(v.Warnings, "WARNING: bridge-nf-call-ip6tables is disabled")
 	}
-	if daemon.configStore.OOMScoreAdjust != 0 {
-		v.Warnings = append(v.Warnings, `DEPRECATED: The "oom-score-adjust" config parameter and the dockerd "--oom-score-adjust" option will be removed in the next release`)
-	}
 }
 
 func (daemon *Daemon) fillPlatformVersion(v *types.Version) {

libcontainerd/supervisor/remote_daemon_options_linux.go

@@ -1,11 +0,0 @@
-package supervisor // import "github.com/docker/docker/libcontainerd/supervisor"
-
-// WithOOMScore defines the oom_score_adj to set for the containerd process.
-//
-// Deprecated: setting the oom-score-adjust from the daemon itself is deprecated, and should be handled by the process-manager starting the daemon instead.
-func WithOOMScore(score int) DaemonOpt {
-	return func(r *remote) error {
-		r.oomScore = score
-		return nil
-	}
-}