diff --git a/io_unix.go b/io_unix.go
index d8d015b8d..cde30d452 100644
--- a/io_unix.go
+++ b/io_unix.go
@@ -36,7 +36,6 @@ func copyIO(fifos *FIFOSet, ioset *ioSet, tty bool) (_ *wgCloser, err error) {
 	var (
 		f           io.ReadWriteCloser
 		set         []io.Closer
-		cwg         sync.WaitGroup
 		ctx, cancel = context.WithCancel(context.Background())
 		wg          = &sync.WaitGroup{}
 	)
@@ -53,9 +52,7 @@ func copyIO(fifos *FIFOSet, ioset *ioSet, tty bool) (_ *wgCloser, err error) {
 		return nil, err
 	}
 	set = append(set, f)
-	cwg.Add(1)
 	go func(w io.WriteCloser) {
-		cwg.Done()
 		io.Copy(w, ioset.in)
 		w.Close()
 	}(f)
@@ -65,9 +62,7 @@ func copyIO(fifos *FIFOSet, ioset *ioSet, tty bool) (_ *wgCloser, err error) {
 	}
 	set = append(set, f)
 	wg.Add(1)
-	cwg.Add(1)
 	go func(r io.ReadCloser) {
-		cwg.Done()
 		io.Copy(ioset.out, r)
 		r.Close()
 		wg.Done()
@@ -80,15 +75,12 @@ func copyIO(fifos *FIFOSet, ioset *ioSet, tty bool) (_ *wgCloser, err error) {
 
 	if !tty {
 		wg.Add(1)
-		cwg.Add(1)
 		go func(r io.ReadCloser) {
-			cwg.Done()
 			io.Copy(ioset.err, r)
 			r.Close()
 			wg.Done()
 		}(f)
 	}
-	cwg.Wait()
 	return &wgCloser{
 		wg:     wg,
 		dir:    fifos.Dir,
diff --git a/linux/shim/client.go b/linux/shim/client.go
index f34403ceb..2b5016fc5 100644
--- a/linux/shim/client.go
+++ b/linux/shim/client.go
@@ -49,7 +49,6 @@ func WithStart(binary, address string, debug bool) ClientOpt {
 			if err != nil {
 				terminate(cmd)
 			}
-			reaper.Default.Delete(cmd.Process.Pid)
 		}()
 		log.G(ctx).WithFields(logrus.Fields{
 			"pid":     cmd.Process.Pid,
diff --git a/metrics/cgroups/cgroups.go b/metrics/cgroups/cgroups.go
index 31d2f2148..5ef16c0c3 100644
--- a/metrics/cgroups/cgroups.go
+++ b/metrics/cgroups/cgroups.go
@@ -65,7 +65,6 @@ func (m *cgroupsMonitor) Monitor(c runtime.Task) error {
 func (m *cgroupsMonitor) Stop(c runtime.Task) error {
 	info := c.Info()
 	m.collector.Remove(info.ID, info.Namespace)
-	m.oom.Remove(info.ID, info.Namespace)
 	return nil
 }
 
diff --git a/metrics/cgroups/oom.go b/metrics/cgroups/oom.go
index fd1845c1f..47d979f58 100644
--- a/metrics/cgroups/oom.go
+++ b/metrics/cgroups/oom.go
@@ -9,7 +9,6 @@ import (
 
 	"github.com/containerd/cgroups"
 	metrics "github.com/docker/go-metrics"
-	"github.com/prometheus/client_golang/prometheus"
 	"github.com/sirupsen/logrus"
 )
 
@@ -19,21 +18,20 @@ func NewOOMCollector(ns *metrics.Namespace) (*OOMCollector, error) {
 		return nil, err
 	}
 	c := &OOMCollector{
-		fd:   fd,
-		set:  make(map[uintptr]*oom),
-		desc: ns.NewDesc("memory_oom", "The number of times a container has received an oom event", metrics.Total, "container_id", "namespace"),
+		fd:        fd,
+		memoryOOM: ns.NewLabeledGauge("memory_oom", "The number of times a container received an oom event", metrics.Total, "container_id", "namespace"),
+		set:       make(map[uintptr]*oom),
 	}
 	go c.start()
-	ns.Add(c)
 	return c, nil
 }
 
 type OOMCollector struct {
 	mu sync.Mutex
 
-	fd   int
-	set  map[uintptr]*oom
-	desc *prometheus.Desc
+	memoryOOM metrics.LabeledGauge
+	fd        int
+	set       map[uintptr]*oom
 }
 
 type oom struct {
@@ -41,7 +39,6 @@ type oom struct {
 	namespace string
 	c         cgroups.Cgroup
 	triggers  []Trigger
-	count     int
 }
 
 func (o *OOMCollector) Add(id, namespace string, cg cgroups.Cgroup, triggers ...Trigger) error {
@@ -53,10 +50,12 @@ func (o *OOMCollector) Add(id, namespace string, cg cgroups.Cgroup, triggers ...
 	}
 	o.set[fd] = &oom{
 		id:        id,
-		namespace: namespace,
 		c:         cg,
 		triggers:  triggers,
+		namespace: namespace,
 	}
+	// set the gauge's default value
+	o.memoryOOM.WithValues(id, namespace).Set(0)
 	event := unix.EpollEvent{
 		Fd:     int32(fd),
 		Events: unix.EPOLLHUP | unix.EPOLLIN | unix.EPOLLERR,
@@ -67,37 +66,11 @@ func (o *OOMCollector) Add(id, namespace string, cg cgroups.Cgroup, triggers ...
 	return nil
 }
 
-func (o *OOMCollector) Remove(id, namespace string) {
-	o.mu.Lock()
-	defer o.mu.Unlock()
-	for fd, t := range o.set {
-		if t.id == id && t.namespace == namespace {
-			unix.Close(int(fd))
-			delete(o.set, fd)
-			return
-		}
-	}
-}
-
 // Close closes the epoll fd
 func (o *OOMCollector) Close() error {
 	return unix.Close(int(o.fd))
 }
 
-func (o *OOMCollector) Describe(ch chan<- *prometheus.Desc) {
-	o.mu.Lock()
-	defer o.mu.Unlock()
-	ch <- o.desc
-}
-
-func (o *OOMCollector) Collect(ch chan<- prometheus.Metric) {
-	o.mu.Lock()
-	defer o.mu.Unlock()
-	for _, t := range o.set {
-		ch <- prometheus.MustNewConstMetric(o.desc, prometheus.GaugeValue, float64(t.count), t.id, t.namespace)
-	}
-}
-
 func (o *OOMCollector) start() {
 	var events [128]unix.EpollEvent
 	for {
@@ -134,7 +107,7 @@ func (o *OOMCollector) process(fd uintptr, event uint32) {
 		unix.Close(int(fd))
 		return
 	}
-	info.count++
+	o.memoryOOM.WithValues(info.id, info.namespace).Inc(1)
 	for _, t := range info.triggers {
 		t(info.id, info.c)
 	}
diff --git a/runtime/task.go b/runtime/task.go
index 62fa171e6..4a5685e10 100644
--- a/runtime/task.go
+++ b/runtime/task.go
@@ -9,6 +9,7 @@ import (
 type TaskInfo struct {
 	ID        string
 	Runtime   string
+	Spec      []byte
 	Namespace string
 }