Ensure CPU quota/period updates are sent to runc

Fixes an issue where if cpu quota/period is sent via the update API, the
values are updated in the stored container data but not actually sent to
the running container.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

daemon/update_linux.go

@@ -30,6 +30,13 @@ func toContainerdResources(resources container.Resources) *libcontainerd.Resourc
 		period = uint64(100 * time.Millisecond / time.Microsecond)
 		quota = resources.NanoCPUs * int64(period) / 1e9
 	}
+	if quota == 0 && resources.CPUQuota != 0 {
+		quota = resources.CPUQuota
+	}
+	if period == 0 && resources.CPUPeriod != 0 {
+		period = uint64(resources.CPUPeriod)
+	}
+
 	r.CPU.Period = &period
 	r.CPU.Quota = &quota
 

integration/container/update_linux_test.go

@@ -0,0 +1,108 @@
+package container
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/integration/util/request"
+	"github.com/docker/docker/pkg/stdcopy"
+)
+
+func TestUpdateCPUQUota(t *testing.T) {
+	t.Parallel()
+
+	client := request.NewAPIClient(t)
+	ctx := context.Background()
+
+	c, err := client.ContainerCreate(ctx, &container.Config{
+		Image: "busybox",
+		Cmd:   []string{"top"},
+	}, nil, nil, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		if err := client.ContainerRemove(ctx, c.ID, types.ContainerRemoveOptions{Force: true}); err != nil {
+			panic(fmt.Sprintf("failed to clean up after test: %v", err))
+		}
+	}()
+
+	if err := client.ContainerStart(ctx, c.ID, types.ContainerStartOptions{}); err != nil {
+		t.Fatal(err)
+	}
+
+	for _, test := range []struct {
+		desc   string
+		update int64
+	}{
+		{desc: "some random value", update: 15000},
+		{desc: "a higher value", update: 20000},
+		{desc: "a lower value", update: 10000},
+		{desc: "unset value", update: -1},
+	} {
+		if _, err := client.ContainerUpdate(ctx, c.ID, container.UpdateConfig{
+			Resources: container.Resources{
+				CPUQuota: test.update,
+			},
+		}); err != nil {
+			t.Fatal(err)
+		}
+
+		inspect, err := client.ContainerInspect(ctx, c.ID)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if inspect.HostConfig.CPUQuota != test.update {
+			t.Fatalf("quota not updated in the API, expected %d, got: %d", test.update, inspect.HostConfig.CPUQuota)
+		}
+
+		execCreate, err := client.ContainerExecCreate(ctx, c.ID, types.ExecConfig{
+			Cmd:          []string{"/bin/cat", "/sys/fs/cgroup/cpu/cpu.cfs_quota_us"},
+			AttachStdout: true,
+			AttachStderr: true,
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		attach, err := client.ContainerExecAttach(ctx, execCreate.ID, types.ExecStartCheck{})
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if err := client.ContainerExecStart(ctx, execCreate.ID, types.ExecStartCheck{}); err != nil {
+			t.Fatal(err)
+		}
+
+		buf := bytes.NewBuffer(nil)
+		ready := make(chan error)
+
+		go func() {
+			_, err := stdcopy.StdCopy(buf, buf, attach.Reader)
+			ready <- err
+		}()
+
+		select {
+		case <-time.After(60 * time.Second):
+			t.Fatal("timeout waiting for exec to complete")
+		case err := <-ready:
+			if err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		actual := strings.TrimSpace(buf.String())
+		if actual != strconv.Itoa(int(test.update)) {
+			t.Fatalf("expected cgroup value %d, got: %s", test.update, actual)
+		}
+	}
+
+}