Migrate oom watcher not relying on cAdviosr any more, it is part of plan

of removing cAdvisor from k8s.
For more informations about this plan, please refer:
https://github.com/kubernetes/kubernetes/issues/68522

pkg/kubelet/BUILD

@@ -21,7 +21,6 @@ go_library(
         "kubelet_pods.go",
         "kubelet_resources.go",
         "kubelet_volumes.go",
-        "oom_watcher.go",
         "pod_container_deletor.go",
         "pod_workers.go",
         "reason_cache.go",
@@ -72,6 +71,7 @@ go_library(
         "//pkg/kubelet/network/dns:go_default_library",
         "//pkg/kubelet/nodelease:go_default_library",
         "//pkg/kubelet/nodestatus:go_default_library",
+        "//pkg/kubelet/oom:go_default_library",
         "//pkg/kubelet/pleg:go_default_library",
         "//pkg/kubelet/pod:go_default_library",
         "//pkg/kubelet/preemption:go_default_library",
@@ -144,7 +144,6 @@ go_library(
         "//staging/src/k8s.io/node-api/pkg/client/clientset/versioned:go_default_library",
         "//third_party/forked/golang/expansion:go_default_library",
         "//vendor/github.com/golang/groupcache/lru:go_default_library",
-        "//vendor/github.com/google/cadvisor/events:go_default_library",
         "//vendor/github.com/google/cadvisor/info/v1:go_default_library",
         "//vendor/github.com/google/cadvisor/info/v2:go_default_library",
         "//vendor/k8s.io/klog:go_default_library",
@@ -168,7 +167,6 @@ go_test(
         "kubelet_test.go",
         "kubelet_volumes_linux_test.go",
         "kubelet_volumes_test.go",
-        "oom_watcher_test.go",
         "pod_container_deletor_test.go",
         "pod_workers_test.go",
         "reason_cache_test.go",
@@ -297,6 +295,7 @@ filegroup(
         "//pkg/kubelet/network:all-srcs",
         "//pkg/kubelet/nodelease:all-srcs",
         "//pkg/kubelet/nodestatus:all-srcs",
+        "//pkg/kubelet/oom:all-srcs",
         "//pkg/kubelet/pleg:all-srcs",
         "//pkg/kubelet/pod:all-srcs",
         "//pkg/kubelet/preemption:all-srcs",

pkg/kubelet/kubelet.go

@@ -80,6 +80,7 @@ import (
 	"k8s.io/kubernetes/pkg/kubelet/metrics/collectors"
 	"k8s.io/kubernetes/pkg/kubelet/network/dns"
 	"k8s.io/kubernetes/pkg/kubelet/nodelease"
+	oomwatcher "k8s.io/kubernetes/pkg/kubelet/oom"
 	"k8s.io/kubernetes/pkg/kubelet/pleg"
 	kubepod "k8s.io/kubernetes/pkg/kubelet/pod"
 	"k8s.io/kubernetes/pkg/kubelet/preemption"
@@ -469,7 +470,7 @@ func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 
 	containerRefManager := kubecontainer.NewRefManager()
 
-	oomWatcher := NewOOMWatcher(kubeDeps.CAdvisorInterface, kubeDeps.Recorder)
+	oomWatcher := oomwatcher.NewOOMWatcher(kubeDeps.Recorder)
 
 	clusterDNS := make([]net.IP, 0, len(kubeCfg.ClusterDNS))
 	for _, ipEntry := range kubeCfg.ClusterDNS {
@@ -1088,7 +1089,7 @@ type Kubelet struct {
 	os kubecontainer.OSInterface
 
 	// Watcher of out of memory events.
-	oomWatcher OOMWatcher
+	oomWatcher oomwatcher.OOMWatcher
 
 	// Monitor resource usage
 	resourceAnalyzer serverstats.ResourceAnalyzer

pkg/kubelet/oom/BUILD

@@ -0,0 +1,82 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "oom_watcher_linux.go",
+        "oom_watcher_unsupported.go",
+        "types.go",
+    ],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/oom",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//staging/src/k8s.io/api/core/v1:go_default_library",
+    ] + select({
+        "@io_bazel_rules_go//go/platform:android": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:darwin": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:dragonfly": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:freebsd": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:linux": [
+            "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+            "//staging/src/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+            "//vendor/github.com/google/cadvisor/utils/oomparser:go_default_library",
+            "//vendor/k8s.io/klog:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:nacl": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:netbsd": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:openbsd": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:plan9": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:solaris": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "@io_bazel_rules_go//go/platform:windows": [
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+        ],
+        "//conditions:default": [],
+    }),
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["oom_watcher_linux_test.go"],
+    embed = [":go_default_library"],
+    deps = select({
+        "@io_bazel_rules_go//go/platform:linux": [
+            "//staging/src/k8s.io/api/core/v1:go_default_library",
+            "//staging/src/k8s.io/client-go/tools/record:go_default_library",
+            "//vendor/github.com/stretchr/testify/assert:go_default_library",
+        ],
+        "//conditions:default": [],
+    }),
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

pkg/kubelet/oom/oom_watcher_linux.go

@@ -1,3 +1,5 @@
+// +build linux
+
 /*
 Copyright 2015 The Kubernetes Authors.
 
@@ -14,61 +16,52 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package kubelet
+package oom
 
 import (
-	"github.com/google/cadvisor/events"
-	cadvisorapi "github.com/google/cadvisor/info/v1"
 	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/client-go/tools/record"
 	"k8s.io/klog"
-	"k8s.io/kubernetes/pkg/kubelet/cadvisor"
+
+	"github.com/google/cadvisor/utils/oomparser"
 )
 
-// OOMWatcher defines the interface of OOM watchers.
-type OOMWatcher interface {
-	Start(ref *v1.ObjectReference) error
-}
-
 type realOOMWatcher struct {
-	cadvisor cadvisor.Interface
 	recorder record.EventRecorder
 }
 
+var _ OOMWatcher = &realOOMWatcher{}
+
 // NewOOMWatcher creates and initializes a OOMWatcher based on parameters.
-func NewOOMWatcher(cadvisor cadvisor.Interface, recorder record.EventRecorder) OOMWatcher {
+func NewOOMWatcher(recorder record.EventRecorder) OOMWatcher {
 	return &realOOMWatcher{
-		cadvisor: cadvisor,
 		recorder: recorder,
 	}
 }
 
 const systemOOMEvent = "SystemOOM"
 
-// Watches cadvisor for system oom's and records an event for every system oom encountered.
+// Watches for system oom's and records an event for every system oom encountered.
 func (ow *realOOMWatcher) Start(ref *v1.ObjectReference) error {
-	request := events.Request{
+	oomLog, err := oomparser.New()
-		EventType: map[cadvisorapi.EventType]bool{
-			cadvisorapi.EventOom: true,
-		},
-		ContainerName:        "/",
-		IncludeSubcontainers: false,
-	}
-	eventChannel, err := ow.cadvisor.WatchEvents(&request)
 	if err != nil {
 		return err
 	}
+	outStream := make(chan *oomparser.OomInstance, 10)
+	go oomLog.StreamOoms(outStream)
 
 	go func() {
 		defer runtime.HandleCrash()
 
-		for event := range eventChannel.GetChannel() {
+		for event := range outStream {
-			klog.V(2).Infof("Got sys oom event from cadvisor: %v", event)
+			if event.ContainerName == "/" {
-			ow.recorder.PastEventf(ref, metav1.Time{Time: event.Timestamp}, v1.EventTypeWarning, systemOOMEvent, "System OOM encountered")
+				klog.V(1).Infof("Got sys oom event: %v", event)
+				ow.recorder.PastEventf(ref, metav1.Time{Time: event.TimeOfDeath}, v1.EventTypeWarning, systemOOMEvent, "System OOM encountered")
 			}
-		klog.Errorf("Unexpectedly stopped receiving OOM notifications from cAdvisor")
+		}
+		klog.Errorf("Unexpectedly stopped receiving OOM notifications")
 	}()
 	return nil
 }

pkg/kubelet/oom/oom_watcher_linux_test.go

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package kubelet
+package oom
 
 import (
 	"testing"
@@ -23,14 +23,12 @@ import (
 
 	"k8s.io/api/core/v1"
 	"k8s.io/client-go/tools/record"
-	cadvisortest "k8s.io/kubernetes/pkg/kubelet/cadvisor/testing"
 )
 
 func TestBasic(t *testing.T) {
 	fakeRecorder := &record.FakeRecorder{}
-	mockCadvisor := &cadvisortest.Fake{}
 	node := &v1.ObjectReference{}
-	oomWatcher := NewOOMWatcher(mockCadvisor, fakeRecorder)
+	oomWatcher := NewOOMWatcher(fakeRecorder)
 	assert.NoError(t, oomWatcher.Start(node))
 
 	// TODO: Improve this test once cadvisor exports events.EventChannel as an interface

pkg/kubelet/oom/oom_watcher_unsupported.go

@@ -0,0 +1,35 @@
+// +build !linux
+
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package oom
+
+import (
+	"k8s.io/api/core/v1"
+	"k8s.io/client-go/tools/record"
+)
+
+type oomWatcherUnsupported struct{}
+
+var _ OOMWatcher = new(oomWatcherUnsupported)
+
+func NewOOMWatcher(_ record.EventRecorder) OOMWatcher {
+	return &oomWatcherUnsupported{}
+}
+
+func (ow *oomWatcherUnsupported) Start(_ *v1.ObjectReference) error {
+	return nil
+}

pkg/kubelet/oom/types.go

@@ -0,0 +1,25 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package oom
+
+import (
+	"k8s.io/api/core/v1"
+)
+
+// OOMWatcher defines the interface of OOM watchers.
+type OOMWatcher interface {
+	Start(ref *v1.ObjectReference) error
+}