Add --blkio-weight option to run subcommand

README.md

@@ -311,6 +311,7 @@ Cgroup flags:
 - :whale: `--memory`: Memory limit
 - :whale: `--pids-limit`: Tune container pids limit
 - :nerd_face: `--cgroup-conf`: Configure cgroup v2 (key=value)
+- :whale: `blkio-weight`: Block IO (relative weight), between 10 and 1000, or 0 to disable (default 0)
 - :whale: `--cgroupns=(host|private)`: Cgroup namespace to use
   - Default: "private" on cgroup v2 hosts, "host" on cgroup v1 hosts
 - :whale: `--device`: Add a host device to the container

cmd/nerdctl/run.go

@@ -135,6 +135,7 @@ func newRunCommand() *cobra.Command {
 	})
 	runCommand.Flags().Int("pids-limit", -1, "Tune container pids limit (set -1 for unlimited)")
 	runCommand.Flags().StringSlice("cgroup-conf", nil, "Configure cgroup v2 (key=value)")
+	runCommand.Flags().Uint16("blkio-weight", 0, "Block IO (relative weight), between 10 and 1000, or 0 to disable (default 0)")
 	runCommand.Flags().String("cgroupns", defaults.CgroupnsMode(), `Cgroup namespace to use, the default depends on the cgroup version ("host"|"private")`)
 	runCommand.RegisterFlagCompletionFunc("cgroupns", func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 		return []string{"host", "private"}, cobra.ShellCompDirectiveNoFileComp

cmd/nerdctl/run_cgroup_linux.go

@@ -20,6 +20,8 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io/fs"
+	"os"
 	"path/filepath"
 	"strings"
 
@@ -133,6 +135,27 @@ func generateCgroupOpts(cmd *cobra.Command, id string) ([]oci.SpecOpts, error) {
 	}
 	opts = append(opts, withUnified(unifieds))
 
+	blkioWeight, err := cmd.Flags().GetUint16("blkio-weight")
+	if err != nil {
+		return nil, err
+	}
+	if infoutil.CgroupsVersion() == "1" {
+		blkioController := "/sys/fs/cgroup/blkio"
+		blkioWeightPath := filepath.Join(blkioController, "blkio.weight")
+		if _, err := os.Stat(blkioWeightPath); errors.Is(err, fs.ErrNotExist) {
+			// if bfq io scheduler is used, the blkio.weight knob will be exposed as blkio.bfq.weight
+			blkioBfqWeightPath := filepath.Join(blkioController, "blkio.bfq.weight")
+			if _, err := os.Stat(blkioBfqWeightPath); errors.Is(err, fs.ErrNotExist) {
+				logrus.Warn("kernel support for cgroup blkio weight missing, weight discarded")
+				blkioWeight = 0
+			}
+		}
+	}
+	if blkioWeight > 0 && blkioWeight < 10 || blkioWeight > 1000 {
+		return nil, errors.New("range of blkio weight is from 10 to 1000")
+	}
+	opts = append(opts, withBlkioWeight(blkioWeight))
+
 	cgroupns, err := cmd.Flags().GetString("cgroupns")
 	if err != nil {
 		return nil, err
@@ -224,3 +247,13 @@ func withUnified(unified map[string]string) oci.SpecOpts {
 		return nil
 	}
 }
+
+func withBlkioWeight(blkioWeight uint16) oci.SpecOpts {
+	return func(_ context.Context, _ oci.Client, _ *containers.Container, s *oci.Spec) error {
+		if blkioWeight == 0 {
+			return nil
+		}
+		s.Linux.Resources.BlockIO = &specs.LinuxBlockIO{Weight: &blkioWeight}
+		return nil
+	}
+}

cmd/nerdctl/run_test.go

@@ -209,6 +209,17 @@ func TestRunCgroupConf(t *testing.T) {
 		"sh", "-ec", "cd /sys/fs/cgroup && cat memory.high").AssertOutContains("33554432")
 }
 
+func TestRunBlkioWeightCgroupV2(t *testing.T) {
+	if cgroups.Mode() != cgroups.Unified {
+		t.Skip("test requires cgroup v2")
+	}
+	base := testutil.NewBase(t)
+
+	// when bfq io scheduler is used, the io.weight knob is exposed as io.bfq.weight
+	base.Cmd("run", "--rm", "--blkio-weight", "300", testutil.AlpineImage,
+		"sh", "-ec", "cd /sys/fs/cgroup && cat io.bfq.weight").AssertOutContains("300")
+}
+
 func TestRunAddHost(t *testing.T) {
 	base := testutil.NewBase(t)
 	base.Cmd("run", "--rm", "--add-host", "testing.example.com:10.0.0.1", testutil.AlpineImage, "sh", "-c", "cat /etc/hosts").AssertOutWithFunc(func(stdout string) error {