Node-level Checkpointing manager

hack/.golint_failures

@@ -163,6 +163,9 @@ pkg/kubelet/apis/kubeletconfig
 pkg/kubelet/apis/kubeletconfig/v1beta1
 pkg/kubelet/cadvisor
 pkg/kubelet/cadvisor/testing
+pkg/kubelet/checkpoint
+pkg/kubelet/checkpointmanager/checksum
+pkg/kubelet/checkpointmanager/testing/example_checkpoint_formats/v1
 pkg/kubelet/client
 pkg/kubelet/cm
 pkg/kubelet/cm/util

pkg/kubelet/BUILD

@@ -246,6 +246,7 @@ filegroup(
         "//pkg/kubelet/cadvisor:all-srcs",
         "//pkg/kubelet/certificate:all-srcs",
         "//pkg/kubelet/checkpoint:all-srcs",
+        "//pkg/kubelet/checkpointmanager:all-srcs",
         "//pkg/kubelet/client:all-srcs",
         "//pkg/kubelet/cm:all-srcs",
         "//pkg/kubelet/config:all-srcs",

pkg/kubelet/checkpointmanager/BUILD

+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+    "go_test",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["checkpoint_manager.go"],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/checkpointmanager",
+    deps = [
+        "//pkg/kubelet/checkpointmanager/errors:go_default_library",
+        "//pkg/kubelet/util/store:go_default_library",
+        "//pkg/util/filesystem:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["checkpoint_manager_test.go"],
+    embed = [":go_default_library"],
+    deps = [
+        "//pkg/kubelet/checkpointmanager/errors:go_default_library",
+        "//pkg/kubelet/checkpointmanager/testing:go_default_library",
+        "//pkg/kubelet/checkpointmanager/testing/example_checkpoint_formats/v1:go_default_library",
+        "//vendor/github.com/stretchr/testify/assert:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [
+        ":package-srcs",
+        "//pkg/kubelet/checkpointmanager/checksum:all-srcs",
+        "//pkg/kubelet/checkpointmanager/errors:all-srcs",
+        "//pkg/kubelet/checkpointmanager/testing:all-srcs",
+    ],
+    tags = ["automanaged"],
+)

pkg/kubelet/checkpointmanager/README.md

+## DISCLAIMER
+Sig-Node community has reached a general consensus, as a best practice, to
+avoid introducing any new checkpointing support. We reached this understanding
+after struggling with some hard-to-debug issues in the production environments
+caused by the checkpointing.
+
+## Introduction
+This folder contains a framework & primitives, Checkpointing Manager, which is
+used by several other Kubelet submodules, `dockershim`, `devicemanager`, `pods`
+and `cpumanager`, to implement checkpointing at each submodule level. As already
+explained in above `Disclaimer` section, think twice before introducing any further
+checkpointing in Kubelet. If still checkpointing is required, then this folder
+provides the common APIs and the framework for implementing checkpointing.
+Using same APIs across all the submodules will help maintaining consistency at
+Kubelet level.
+
+Below is the history of checkpointing support in Kubelet.
+
+| Package | First checkpointing support merged on | PR link |
+| ------- | --------------------------------------| ------- |
+|kubelet/dockershim | Feb 3, 2017 | [[CRI] Implement Dockershim Checkpoint](https://github.com/kubernetes/kubernetes/pull/39903)
+|devicemanager| Sep 6, 2017 | [Deviceplugin checkpoint](https://github.com/kubernetes/kubernetes/pull/51744)
+| kubelet/pod | Nov 22, 2017 | [Initial basic bootstrap-checkpoint support](https://github.com/kubernetes/kubernetes/pull/50984)
+|cpumanager| Oct 27, 2017 |[Add file backed state to cpu manager ](https://github.com/kubernetes/kubernetes/pull/54408)

pkg/kubelet/checkpointmanager/checkpoint_manager.go

+/*
+Copyright 2018 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 checkpointmanager
+
+import (
+	"fmt"
+
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/errors"
+	utilstore "k8s.io/kubernetes/pkg/kubelet/util/store"
+	utilfs "k8s.io/kubernetes/pkg/util/filesystem"
+)
+
+// Checkpoint provides the process checkpoint data
+type Checkpoint interface {
+	MarshalCheckpoint() ([]byte, error)
+	UnmarshalCheckpoint(blob []byte) error
+	VerifyChecksum() error
+}
+
+// CheckpointManager provides the interface to manage checkpoint
+type CheckpointManager interface {
+	// CreateCheckpoint persists checkpoint in CheckpointStore. checkpointKey is the key for utilstore to locate checkpoint.
+	// For file backed utilstore, checkpointKey is the file name to write the checkpoint data.
+	CreateCheckpoint(checkpointKey string, checkpoint Checkpoint) error
+	// GetCheckpoint retrieves checkpoint from CheckpointStore.
+	GetCheckpoint(checkpointKey string, checkpoint Checkpoint) error
+	// WARNING: RemoveCheckpoint will not return error if checkpoint does not exist.
+	RemoveCheckpoint(checkpointKey string) error
+	// ListCheckpoint returns the list of existing checkpoints.
+	ListCheckpoints() ([]string, error)
+}
+
+// impl is an implementation of CheckpointManager. It persists checkpoint in CheckpointStore
+type impl struct {
+	path  string
+	store utilstore.Store
+}
+
+func NewCheckpointManager(checkpointDir string) (CheckpointManager, error) {
+	fstore, err := utilstore.NewFileStore(checkpointDir, utilfs.DefaultFs{})
+	if err != nil {
+		return nil, err
+	}
+
+	return &impl{path: checkpointDir, store: fstore}, nil
+}
+
+// CreateCheckpoint persists checkpoint in CheckpointStore.
+func (manager *impl) CreateCheckpoint(checkpointKey string, checkpoint Checkpoint) error {
+	manager.mutex.Lock()
+	defer manager.mutex.Unlock()
+	blob, err := checkpoint.MarshalCheckpoint()
+	if err != nil {
+		return err
+	}
+	return manager.store.Write(checkpointKey, blob)
+}
+
+// GetCheckpoint retrieves checkpoint from CheckpointStore.
+func (manager *impl) GetCheckpoint(checkpointKey string, checkpoint Checkpoint) error {
+	manager.mutex.Lock()
+	defer manager.mutex.Unlock()
+	blob, err := manager.store.Read(checkpointKey)
+	if err != nil {
+		if err == utilstore.ErrKeyNotFound {
+			return errors.ErrCheckpointNotFound
+		}
+		return err
+	}
+	err = checkpoint.UnmarshalCheckpoint(blob)
+	if err == nil {
+		err = checkpoint.VerifyChecksum()
+	}
+	return err
+}
+
+func (manager *impl) RemoveCheckpoint(checkpointKey string) error {
+	manager.mutex.Lock()
+	defer manager.mutex.Unlock()
+	return manager.store.Delete(checkpointKey)
+}
+
+// ListCheckpoints returns the list of existing checkpoints.
+func (manager *impl) ListCheckpoints() ([]string, error) {
+	manager.mutex.Lock()
+	defer manager.mutex.Unlock()
+	keys, err := manager.store.List()
+	if err != nil {
+		return []string{}, fmt.Errorf("failed to list checkpoint store: %v", err)
+	}
+	return keys, nil
+}

pkg/kubelet/checkpointmanager/checkpoint_manager_test.go

+/*
+Copyright 2017 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 checkpointmanager
+
+import (
+	"encoding/json"
+	"hash/fnv"
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/errors"
+	utilstore "k8s.io/kubernetes/pkg/kubelet/checkpointmanager/testing"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/testing/example_checkpoint_formats/v1"
+)
+
+var testStore *utilstore.MemStore
+
+type FakeCheckpoint interface {
+	Checkpoint
+	GetData() ([]*PortMapping, bool)
+}
+
+// Data contains all types of data that can be stored in the checkpoint.
+type Data struct {
+	PortMappings []*PortMapping `json:"port_mappings,omitempty"`
+	HostNetwork  bool           `json:"host_network,omitempty"`
+}
+
+type CheckpointDataV2 struct {
+	PortMappings []*PortMapping `json:"port_mappings,omitempty"`
+	HostNetwork  bool           `json:"host_network,omitempty"`
+	V2Field      string         `json:"v2field"`
+}
+
+type protocol string
+
+// portMapping is the port mapping configurations of a sandbox.
+type portMapping struct {
+	// protocol of the port mapping.
+	Protocol *protocol
+	// Port number within the container.
+	ContainerPort *int32
+	// Port number on the host.
+	HostPort *int32
+}
+
+// CheckpointData is a sample example structure to be used in test cases for checkpointing
+type CheckpointData struct {
+	Version  string
+	Name     string
+	Data     *Data
+	Checksum checksum.Checksum
+}
+
+func newFakeCheckpointV1(name string, portMappings []*PortMapping, hostNetwork bool) FakeCheckpoint {
+	return &CheckpointData{
+		Version: "v1",
+		Name:    name,
+		Data: &Data{
+			PortMappings: portMappings,
+			HostNetwork:  hostNetwork,
+		},
+	}
+}
+
+func (cp *CheckpointData) MarshalCheckpoint() ([]byte, error) {
+	cp.Checksum = checksum.New(*cp.Data)
+	return json.Marshal(*cp)
+}
+
+func (cp *CheckpointData) UnmarshalCheckpoint(blob []byte) error {
+	return json.Unmarshal(blob, cp)
+}
+
+func (cp *CheckpointData) VerifyChecksum() error {
+	return cp.Checksum.Verify(*cp.Data)
+}
+
+func (cp *CheckpointData) GetData() ([]*PortMapping, bool) {
+	return cp.Data.PortMappings, cp.Data.HostNetwork
+}
+
+type checkpointDataV2 struct {
+	Version  string
+	Name     string
+	Data     *CheckpointDataV2
+	Checksum checksum.Checksum
+}
+
+func newFakeCheckpointV2(name string, portMappings []*PortMapping, hostNetwork bool) FakeCheckpoint {
+	return &checkpointDataV2{
+		Version: "v2",
+		Name:    name,
+		Data: &CheckpointDataV2{
+			PortMappings: portMappings,
+			HostNetwork:  hostNetwork,
+		},
+	}
+}
+
+func newFakeCheckpointRemoteV1(name string, portMappings []*v1.PortMapping, hostNetwork bool) Checkpoint {
+	return &v1.CheckpointData{
+		Version: "v1",
+		Name:    name,
+		Data: &v1.Data{
+			PortMappings: portMappings,
+			HostNetwork:  hostNetwork,
+		},
+	}
+}
+
+func (cp *checkpointDataV2) MarshalCheckpoint() ([]byte, error) {
+	cp.Checksum = checksum.New(*cp.Data)
+	return json.Marshal(*cp)
+}
+
+func (cp *checkpointDataV2) UnmarshalCheckpoint(blob []byte) error {
+	return json.Unmarshal(blob, cp)
+}
+
+func (cp *checkpointDataV2) VerifyChecksum() error {
+	return cp.Checksum.Verify(*cp.Data)
+}
+
+func (cp *checkpointDataV2) GetData() ([]*PortMapping, bool) {
+	return cp.Data.PortMappings, cp.Data.HostNetwork
+}
+
+func newTestCheckpointManager() CheckpointManager {
+	return &impl{store: testStore}
+}
+
+func TestCheckpointManager(t *testing.T) {
+	var err error
+	testStore = utilstore.NewMemStore()
+	manager := newTestCheckpointManager()
+	port80 := int32(80)
+	port443 := int32(443)
+	proto := protocol("tcp")
+
+	portMappings := []*portMapping{
+		{
+			&proto,
+			&port80,
+			&port80,
+		},
+		{
+			&proto,
+			&port443,
+			&port443,
+		},
+	}
+	checkpoint1 := newFakeCheckpointV1("check1", portMappings, true)
+
+	checkpoints := []struct {
+		checkpointKey     string
+		checkpoint        FakeCheckpoint
+		expectHostNetwork bool
+	}{
+		{
+			"key1",
+			checkpoint1,
+			true,
+		},
+		{
+			"key2",
+			newFakeCheckpointV1("check2", nil, false),
+			false,
+		},
+	}
+
+	for _, tc := range checkpoints {
+		// Test CreateCheckpoints
+		err = manager.CreateCheckpoint(tc.checkpointKey, tc.checkpoint)
+		assert.NoError(t, err)
+
+		// Test GetCheckpoints
+		checkpointOut := newFakeCheckpointV1("", nil, false)
+		err := manager.GetCheckpoint(tc.checkpointKey, checkpointOut)
+		assert.NoError(t, err)
+		actualPortMappings, actualHostNetwork := checkpointOut.GetData()
+		expPortMappings, expHostNetwork := tc.checkpoint.GetData()
+		assert.Equal(t, actualPortMappings, expPortMappings)
+		assert.Equal(t, actualHostNetwork, expHostNetwork)
+	}
+	// Test it fails if tried to read V1 structure into V2, a different structure from the structure which is checkpointed
+	checkpointV2 := newFakeCheckpointV2("", nil, false)
+	err = manager.GetCheckpoint("key1", checkpointV2)
+	assert.EqualError(t, err, "checkpoint is corrupted")
+
+	// Test it fails if tried to read V1 structure into the same structure but defined in another package
+	checkpointRemoteV1 := newFakeCheckpointRemoteV1("", nil, false)
+	err = manager.GetCheckpoint("key1", checkpointRemoteV1)
+	assert.EqualError(t, err, "checkpoint is corrupted")
+
+	// Test it works if tried to read V1 structure using into a new V1 structure
+	checkpointV1 := newFakeCheckpointV1("", nil, false)
+	err = manager.GetCheckpoint("key1", checkpointV1)
+	assert.NoError(t, err)
+
+	// Test corrupt checksum case
+	checkpointOut := newFakeCheckpointV1("", nil, false)
+	blob, err := checkpointOut.MarshalCheckpoint()
+	assert.NoError(t, err)
+	testStore.Write("key1", blob)
+	err = manager.GetCheckpoint("key1", checkpoint1)
+	assert.EqualError(t, err, "checkpoint is corrupted")
+
+	// Test ListCheckpoints
+	keys, err := manager.ListCheckpoints()
+	assert.NoError(t, err)
+	sort.Strings(keys)
+	assert.Equal(t, keys, []string{"key1", "key2"})
+
+	// Test RemoveCheckpoints
+	err = manager.RemoveCheckpoint("key1")
+	assert.NoError(t, err)
+	// Test Remove Nonexisted Checkpoints
+	err = manager.RemoveCheckpoint("key1")
+	assert.NoError(t, err)
+
+	// Test ListCheckpoints
+	keys, err = manager.ListCheckpoints()
+	assert.NoError(t, err)
+	assert.Equal(t, keys, []string{"key2"})
+
+	// Test Get NonExisted Checkpoint
+	checkpointNE := newFakeCheckpointV1("NE", nil, false)
+	err = manager.GetCheckpoint("key1", checkpointNE)
+	assert.Error(t, err)
+}

pkg/kubelet/checkpointmanager/checksum/BUILD

+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["checksum.go"],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/checkpointmanager/checksum",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/kubelet/checkpointmanager/errors:go_default_library",
+        "//pkg/util/hash:go_default_library",
+    ],
+)
+
+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/checkpointmanager/checksum/checksum.go

+/*
+Copyright 2018 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 checksum
+
+import (
+	"hash/fnv"
+
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/errors"
+	hashutil "k8s.io/kubernetes/pkg/util/hash"
+)
+
+// Data to be stored as checkpoint
+type Checksum uint64
+
+// VerifyChecksum verifies that passed checksum is same as calculated checksum
+func (cs Checksum) Verify(data interface{}) error {
+	if cs != New(data) {
+		return errors.ErrCorruptCheckpoint
+	}
+	return nil
+}
+
+func New(data interface{}) Checksum {
+	return Checksum(getChecksum(data))
+}
+
+// Get returns calculated checksum of checkpoint data
+func getChecksum(data interface{}) uint64 {
+	hash := fnv.New32a()
+	hashutil.DeepHashObject(hash, data)
+	return uint64(hash.Sum32())
+}

pkg/kubelet/dockershim/testing/BUILD → pkg/kubelet/checkpointmanager/errors/BUILD

@@ -7,8 +7,8 @@ load(
 
 go_library(
     name = "go_default_library",
-    srcs = ["util.go"],
-    importpath = "k8s.io/kubernetes/pkg/kubelet/dockershim/testing",
+    srcs = ["errors.go"],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/checkpointmanager/errors",
 )
 
 filegroup(

pkg/kubelet/checkpointmanager/errors/errors.go

+/*
+Copyright 2017 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 errors
+
+import "fmt"
+
+var CorruptCheckpointError = fmt.Errorf("checkpoint is corrupted.")
+var CheckpointNotFoundError = fmt.Errorf("checkpoint is not found.")

pkg/kubelet/checkpointmanager/testing/BUILD

+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = ["util.go"],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/checkpointmanager/testing",
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [
+        ":package-srcs",
+        "//pkg/kubelet/checkpointmanager/testing/example_checkpoint_formats/v1:all-srcs",
+    ],
+    tags = ["automanaged"],
+)

pkg/kubelet/checkpointmanager/testing/example_checkpoint_formats/v1/BUILD

+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["types.go"],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/checkpointmanager/testing/example_checkpoint_formats/v1",
+    visibility = ["//visibility:public"],
+    deps = ["//pkg/kubelet/checkpointmanager/checksum:go_default_library"],
+)
+
+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/checkpointmanager/testing/example_checkpoint_formats/v1/types.go

+/*
+Copyright 2018 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 v1
+
+import (
+	"encoding/json"
+
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/checksum"
+)
+
+type protocol string
+
+// portMapping is the port mapping configurations of a sandbox.
+type PortMapping struct {
+	// protocol of the port mapping.
+	Protocol *protocol
+	// Port number within the container.
+	ContainerPort *int32
+	// Port number on the host.
+	HostPort *int32
+}
+
+// CheckpointData contains all types of data that can be stored in the checkpoint.
+type Data struct {
+	PortMappings []*PortMapping `json:"port_mappings,omitempty"`
+	HostNetwork  bool           `json:"host_network,omitempty"`
+}
+
+// CheckpointData is a sample example structure to be used in test cases for checkpointing
+type CheckpointData struct {
+	Version  string
+	Name     string
+	Data     *Data
+	Checksum checksum.Checksum
+}
+
+func (cp *CheckpointData) MarshalCheckpoint() ([]byte, error) {
+	cp.Checksum = checksum.New(*cp.Data)
+	return json.Marshal(*cp)
+}
+
+func (cp *CheckpointData) UnmarshalCheckpoint(blob []byte) error {
+	return json.Unmarshal(blob, cp)
+}
+
+func (cp *CheckpointData) VerifyChecksum() error {
+	return cp.Checksum.Verify(*cp.Data)
+}

pkg/kubelet/cm/devicemanager/BUILD

@@ -15,13 +15,14 @@ go_library(
     deps = [
         "//pkg/apis/core/v1/helper:go_default_library",
         "//pkg/kubelet/apis/deviceplugin/v1beta1:go_default_library",
+        "//pkg/kubelet/checkpointmanager:go_default_library",
+        "//pkg/kubelet/checkpointmanager/errors:go_default_library",
+        "//pkg/kubelet/cm/devicemanager/checkpoint:go_default_library",
         "//pkg/kubelet/config:go_default_library",
         "//pkg/kubelet/container:go_default_library",
         "//pkg/kubelet/lifecycle:go_default_library",
         "//pkg/kubelet/metrics:go_default_library",
-        "//pkg/kubelet/util/store:go_default_library",
         "//pkg/scheduler/schedulercache:go_default_library",
-        "//pkg/util/filesystem:go_default_library",
         "//vendor/github.com/golang/glog:go_default_library",
         "//vendor/google.golang.org/grpc:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",
@@ -39,10 +40,9 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//pkg/kubelet/apis/deviceplugin/v1beta1:go_default_library",
+        "//pkg/kubelet/checkpointmanager:go_default_library",
         "//pkg/kubelet/lifecycle:go_default_library",
-        "//pkg/kubelet/util/store:go_default_library",
         "//pkg/scheduler/schedulercache:go_default_library",
-        "//pkg/util/filesystem:go_default_library",
         "//vendor/github.com/stretchr/testify/assert:go_default_library",
         "//vendor/github.com/stretchr/testify/require:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",
@@ -62,7 +62,10 @@ filegroup(
 
 filegroup(
     name = "all-srcs",
-    srcs = [":package-srcs"],
+    srcs = [
+        ":package-srcs",
+        "//pkg/kubelet/cm/devicemanager/checkpoint:all-srcs",
+    ],
     tags = ["automanaged"],
     visibility = ["//visibility:public"],
 )

pkg/kubelet/cm/devicemanager/checkpoint/BUILD

+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["checkpoint.go"],
+    importpath = "k8s.io/kubernetes/pkg/kubelet/cm/devicemanager/checkpoint",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/kubelet/checkpointmanager:go_default_library",
+        "//pkg/kubelet/checkpointmanager/checksum:go_default_library",
+    ],
+)
+
+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/cm/devicemanager/checkpoint/checkpoint.go

+/*
+Copyright 2017 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 checkpoint
+
+import (
+	"encoding/json"
+
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/checksum"
+)
+
+type DeviceManagerCheckpoint interface {
+	checkpointmanager.Checkpoint
+	GetData() ([]PodDevicesEntry, map[string][]string)
+}
+
+type PodDevicesEntry struct {
+	PodUID        string
+	ContainerName string
+	ResourceName  string
+	DeviceIDs     []string
+	AllocResp     []byte
+}
+
+// checkpointData struct is used to store pod to device allocation information
+// in a checkpoint file.
+// TODO: add version control when we need to change checkpoint format.
+type checkpointData struct {
+	PodDeviceEntries  []PodDevicesEntry
+	RegisteredDevices map[string][]string
+}
+
+type Data struct {
+	Data     checkpointData
+	Checksum checksum.Checksum
+}
+
+// NewDeviceManagerCheckpoint returns an instance of Checkpoint
+func New(devEntries []PodDevicesEntry,
+	devices map[string][]string) DeviceManagerCheckpoint {
+	return &Data{
+		Data: checkpointData{
+			PodDeviceEntries:  devEntries,
+			RegisteredDevices: devices,
+		},
+	}
+}
+
+// MarshalCheckpoint returns marshalled data
+func (cp *Data) MarshalCheckpoint() ([]byte, error) {
+	cp.Checksum = checksum.New(cp.Data)
+	return json.Marshal(*cp)
+}
+
+// UnmarshalCheckpoint returns unmarshalled data
+func (cp *Data) UnmarshalCheckpoint(blob []byte) error {
+	return json.Unmarshal(blob, cp)
+}
+
+// VerifyChecksum verifies that passed checksum is same as calculated checksum
+func (cp *Data) VerifyChecksum() error {
+	return cp.Checksum.Verify(cp.Data)
+}
+
+func (cp *Data) GetData() ([]PodDevicesEntry, map[string][]string) {
+	return cp.Data.PodDeviceEntries, cp.Data.RegisteredDevices
+}

pkg/kubelet/cm/devicemanager/manager.go

@@ -18,7 +18,6 @@ package devicemanager
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"net"
 	"os"
@@ -34,12 +33,13 @@ import (
 	"k8s.io/apimachinery/pkg/util/sets"
 	v1helper "k8s.io/kubernetes/pkg/apis/core/v1/helper"
 	pluginapi "k8s.io/kubernetes/pkg/kubelet/apis/deviceplugin/v1beta1"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/errors"
+	"k8s.io/kubernetes/pkg/kubelet/cm/devicemanager/checkpoint"
 	"k8s.io/kubernetes/pkg/kubelet/config"
 	"k8s.io/kubernetes/pkg/kubelet/lifecycle"
 	"k8s.io/kubernetes/pkg/kubelet/metrics"
-	utilstore "k8s.io/kubernetes/pkg/kubelet/util/store"
 	"k8s.io/kubernetes/pkg/scheduler/schedulercache"
-	utilfs "k8s.io/kubernetes/pkg/util/filesystem"
 )
 
 // ActivePodsFunc is a function that returns a list of pods to reconcile.
@@ -83,9 +83,9 @@ type ManagerImpl struct {
 	allocatedDevices map[string]sets.String
 
 	// podDevices contains pod to allocated device mapping.
-	podDevices podDevices
-	store      utilstore.Store
-	pluginOpts map[string]*pluginapi.DevicePluginOptions
+	podDevices        podDevices
+	pluginOpts        map[string]*pluginapi.DevicePluginOptions
+	checkpointManager checkpointmanager.CheckpointManager
 }
 
 type sourcesReadyStub struct{}
@@ -122,11 +122,11 @@ func newManagerImpl(socketPath string) (*ManagerImpl, error) {
 	// Before that, initializes them to perform no-op operations.
 	manager.activePods = func() []*v1.Pod { return []*v1.Pod{} }
 	manager.sourcesReady = &sourcesReadyStub{}
-	var err error
-	manager.store, err = utilstore.NewFileStore(dir, utilfs.DefaultFs{})
+	checkpointManager, err := checkpointmanager.NewCheckpointManager(dir)
 	if err != nil {
-		return nil, fmt.Errorf("failed to initialize device plugin checkpointing store: %+v", err)
+		return nil, fmt.Errorf("failed to initialize checkpoint manager: %+v", err)
 	}
+	manager.checkpointManager = checkpointManager
 
 	return manager, nil
 }
@@ -454,33 +454,19 @@ func (m *ManagerImpl) GetCapacity() (v1.ResourceList, v1.ResourceList, []string)
 	return capacity, allocatable, deletedResources.UnsortedList()
 }
 
-// checkpointData struct is used to store pod to device allocation information
-// and registered device information in a checkpoint file.
-// TODO: add version control when we need to change checkpoint format.
-type checkpointData struct {
-	PodDeviceEntries  []podDevicesCheckpointEntry
-	RegisteredDevices map[string][]string
-}
-
 // Checkpoints device to container allocation information to disk.
 func (m *ManagerImpl) writeCheckpoint() error {
 	m.mutex.Lock()
-	data := checkpointData{
-		PodDeviceEntries:  m.podDevices.toCheckpointData(),
-		RegisteredDevices: make(map[string][]string),
-	}
+	registeredDevs := make(map[string][]string)
 	for resource, devices := range m.healthyDevices {
-		data.RegisteredDevices[resource] = devices.UnsortedList()
+		registeredDevs[resource] = devices.UnsortedList()
 	}
+	data := checkpoint.New(m.podDevices.toCheckpointData(),
+		registeredDevs)
 	m.mutex.Unlock()
-
-	dataJSON, err := json.Marshal(data)
-	if err != nil {
-		return err
-	}
-	err = m.store.Write(kubeletDeviceManagerCheckpoint, dataJSON)
+	err := m.checkpointManager.CreateCheckpoint(kubeletDeviceManagerCheckpoint, data)
 	if err != nil {
-		return fmt.Errorf("failed to write deviceplugin checkpoint file %q: %v", kubeletDeviceManagerCheckpoint, err)
+		return fmt.Errorf("failed to write checkpoint file %q: %v", kubeletDeviceManagerCheckpoint, err)
 	}
 	return nil
 }
@@ -488,24 +474,23 @@ func (m *ManagerImpl) writeCheckpoint() error {
 // Reads device to container allocation information from disk, and populates
 // m.allocatedDevices accordingly.
 func (m *ManagerImpl) readCheckpoint() error {
-	content, err := m.store.Read(kubeletDeviceManagerCheckpoint)
+	registeredDevs := make(map[string][]string)
+	devEntries := make([]checkpoint.PodDevicesEntry, 0)
+	cp := checkpoint.New(devEntries, registeredDevs)
+	err := m.checkpointManager.GetCheckpoint(kubeletDeviceManagerCheckpoint, cp)
 	if err != nil {
-		if err == utilstore.ErrKeyNotFound {
+		if err == errors.ErrCheckpointNotFound {
+			glog.Warningf("Failed to retrieve checkpoint for %q: %v", kubeletDeviceManagerCheckpoint, err)
 			return nil
 		}
-		return fmt.Errorf("failed to read checkpoint file %q: %v", kubeletDeviceManagerCheckpoint, err)
-	}
-	glog.V(4).Infof("Read checkpoint file %s\n", kubeletDeviceManagerCheckpoint)
-	var data checkpointData
-	if err := json.Unmarshal(content, &data); err != nil {
-		return fmt.Errorf("failed to unmarshal deviceplugin checkpoint data: %v", err)
+		return err
 	}
-
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
-	m.podDevices.fromCheckpointData(data.PodDeviceEntries)
+	podDevices, registeredDevs := cp.GetData()
+	m.podDevices.fromCheckpointData(podDevices)
 	m.allocatedDevices = m.podDevices.devices()
-	for resource := range data.RegisteredDevices {
+	for resource := range registeredDevs {
 		// During start up, creates empty healthyDevices list so that the resource capacity
 		// will stay zero till the corresponding device plugin re-registers.
 		m.healthyDevices[resource] = sets.NewString()

pkg/kubelet/cm/devicemanager/manager_test.go

@@ -34,10 +34,9 @@ import (
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apimachinery/pkg/util/uuid"
 	pluginapi "k8s.io/kubernetes/pkg/kubelet/apis/deviceplugin/v1beta1"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager"
 	"k8s.io/kubernetes/pkg/kubelet/lifecycle"
-	utilstore "k8s.io/kubernetes/pkg/kubelet/util/store"
 	"k8s.io/kubernetes/pkg/scheduler/schedulercache"
-	utilfs "k8s.io/kubernetes/pkg/util/filesystem"
 )
 
 const (
@@ -347,20 +346,19 @@ func constructAllocResp(devices, mounts, envs map[string]string) *pluginapi.Cont
 func TestCheckpoint(t *testing.T) {
 	resourceName1 := "domain1.com/resource1"
 	resourceName2 := "domain2.com/resource2"
-
 	as := assert.New(t)
 	tmpDir, err := ioutil.TempDir("", "checkpoint")
 	as.Nil(err)
-	defer os.RemoveAll(tmpDir)
+	ckm, err := checkpointmanager.NewCheckpointManager(tmpDir)
+	as.Nil(err)
 	testManager := &ManagerImpl{
-		socketdir:        tmpDir,
-		endpoints:        make(map[string]endpoint),
-		healthyDevices:   make(map[string]sets.String),
-		unhealthyDevices: make(map[string]sets.String),
-		allocatedDevices: make(map[string]sets.String),
-		podDevices:       make(podDevices),
+		endpoints:         make(map[string]endpoint),
+		healthyDevices:    make(map[string]sets.String),
+		unhealthyDevices:  make(map[string]sets.String),
+		allocatedDevices:  make(map[string]sets.String),
+		podDevices:        make(podDevices),
+		checkpointManager: ckm,
 	}
-	testManager.store, _ = utilstore.NewFileStore("/tmp/", utilfs.DefaultFs{})
 
 	testManager.podDevices.insert("pod1", "con1", resourceName1,
 		constructDevices([]string{"dev1", "dev2"}),
@@ -479,21 +477,25 @@ func makePod(limits v1.ResourceList) *v1.Pod {
 	}
 }
 
-func getTestManager(tmpDir string, activePods ActivePodsFunc, testRes []TestResource, opts map[string]*pluginapi.DevicePluginOptions) *ManagerImpl {
+func getTestManager(tmpDir string, activePods ActivePodsFunc, testRes []TestResource, opts map[string]*pluginapi.DevicePluginOptions) (*ManagerImpl, error) {
 	monitorCallback := func(resourceName string, added, updated, deleted []pluginapi.Device) {}
+	ckm, err := checkpointmanager.NewCheckpointManager(tmpDir)
+	if err != nil {
+		return nil, err
+	}
 	testManager := &ManagerImpl{
-		socketdir:        tmpDir,
-		callback:         monitorCallback,
-		healthyDevices:   make(map[string]sets.String),
-		unhealthyDevices: make(map[string]sets.String),
-		allocatedDevices: make(map[string]sets.String),
-		endpoints:        make(map[string]endpoint),
-		pluginOpts:       opts,
-		podDevices:       make(podDevices),
-		activePods:       activePods,
-		sourcesReady:     &sourcesReadyStub{},
-	}
-	testManager.store, _ = utilstore.NewFileStore("/tmp/", utilfs.DefaultFs{})
+		socketdir:         tmpDir,
+		callback:          monitorCallback,
+		healthyDevices:    make(map[string]sets.String),
+		unhealthyDevices:  make(map[string]sets.String),
+		allocatedDevices:  make(map[string]sets.String),
+		endpoints:         make(map[string]endpoint),
+		pluginOpts:        opts,
+		podDevices:        make(podDevices),
+		activePods:        activePods,
+		sourcesReady:      &sourcesReadyStub{},
+		checkpointManager: ckm,
+	}
 	for _, res := range testRes {
 		testManager.healthyDevices[res.resourceName] = sets.NewString()
 		for _, dev := range res.devs {
@@ -525,7 +527,7 @@ func getTestManager(tmpDir string, activePods ActivePodsFunc, testRes []TestReso
 			}
 		}
 	}
-	return testManager
+	return testManager, nil
 }
 
 func getTestNodeInfo(allocatable v1.ResourceList) *schedulercache.NodeInfo {
@@ -569,7 +571,8 @@ func TestPodContainerDeviceAllocation(t *testing.T) {
 	defer os.RemoveAll(tmpDir)
 	nodeInfo := getTestNodeInfo(v1.ResourceList{})
 	pluginOpts := make(map[string]*pluginapi.DevicePluginOptions)
-	testManager := getTestManager(tmpDir, podsStub.getActivePods, testResources, pluginOpts)
+	testManager, err := getTestManager(tmpDir, podsStub.getActivePods, testResources, pluginOpts)
+	as.Nil(err)
 
 	testPods := []*v1.Pod{
 		makePod(v1.ResourceList{
@@ -664,7 +667,8 @@ func TestInitContainerDeviceAllocation(t *testing.T) {
 	as.Nil(err)
 	defer os.RemoveAll(tmpDir)
 	pluginOpts := make(map[string]*pluginapi.DevicePluginOptions)
-	testManager := getTestManager(tmpDir, podsStub.getActivePods, testResources, pluginOpts)
+	testManager, err := getTestManager(tmpDir, podsStub.getActivePods, testResources, pluginOpts)
+	as.Nil(err)
 
 	podWithPluginResourcesInInitContainers := &v1.Pod{
 		ObjectMeta: metav1.ObjectMeta{
@@ -742,14 +746,18 @@ func TestSanitizeNodeAllocatable(t *testing.T) {
 
 	as := assert.New(t)
 	monitorCallback := func(resourceName string, added, updated, deleted []pluginapi.Device) {}
+	tmpDir, err := ioutil.TempDir("", "checkpoint")
+	as.Nil(err)
 
+	ckm, err := checkpointmanager.NewCheckpointManager(tmpDir)
+	as.Nil(err)
 	testManager := &ManagerImpl{
-		callback:         monitorCallback,
-		healthyDevices:   make(map[string]sets.String),
-		allocatedDevices: make(map[string]sets.String),
-		podDevices:       make(podDevices),
+		callback:          monitorCallback,
+		allDevices:        make(map[string]sets.String),
+		healthyDevices:    make(map[string]sets.String),
+		podDevices:        make(podDevices),
+		checkpointManager: ckm,
 	}
-	testManager.store, _ = utilstore.NewFileStore("/tmp/", utilfs.DefaultFs{})
 	// require one of resource1 and one of resource2
 	testManager.allocatedDevices[resourceName1] = sets.NewString()
 	testManager.allocatedDevices[resourceName1].Insert(devID1)
@@ -796,7 +804,8 @@ func TestDevicePreStartContainer(t *testing.T) {
 	pluginOpts := make(map[string]*pluginapi.DevicePluginOptions)
 	pluginOpts[res1.resourceName] = &pluginapi.DevicePluginOptions{PreStartRequired: true}
 
-	testManager := getTestManager(tmpDir, podsStub.getActivePods, []TestResource{res1}, pluginOpts)
+	testManager, err := getTestManager(tmpDir, podsStub.getActivePods, []TestResource{res1}, pluginOpts)
+	as.Nil(err)
 
 	ch := make(chan []string, 1)
 	testManager.endpoints[res1.resourceName] = &MockEndpoint{

pkg/kubelet/cm/devicemanager/pod_devices.go

@@ -21,6 +21,7 @@ import (
 
 	"k8s.io/apimachinery/pkg/util/sets"
 	pluginapi "k8s.io/kubernetes/pkg/kubelet/apis/deviceplugin/v1beta1"
+	"k8s.io/kubernetes/pkg/kubelet/cm/devicemanager/checkpoint"
 	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
 )
 
@@ -126,18 +127,9 @@ func (pdev podDevices) devices() map[string]sets.String {
 	return ret
 }
 
-// podDevicesCheckpointEntry is used to record <pod, container> to device allocation information.
-type podDevicesCheckpointEntry struct {
-	PodUID        string
-	ContainerName string
-	ResourceName  string
-	DeviceIDs     []string
-	AllocResp     []byte
-}
-
 // Turns podDevices to checkpointData.
-func (pdev podDevices) toCheckpointData() []podDevicesCheckpointEntry {
-	var data []podDevicesCheckpointEntry
+func (pdev podDevices) toCheckpointData() []checkpoint.PodDevicesEntry {
+	var data []checkpoint.PodDevicesEntry
 	for podUID, containerDevices := range pdev {
 		for conName, resources := range containerDevices {
 			for resource, devices := range resources {
@@ -152,7 +144,7 @@ func (pdev podDevices) toCheckpointData() []podDevicesCheckpointEntry {
 					glog.Errorf("Can't marshal allocResp for %v %v %v: %v", podUID, conName, resource, err)
 					continue
 				}
-				data = append(data, podDevicesCheckpointEntry{podUID, conName, resource, devIds, allocResp})
+				data = append(data, checkpoint.PodDevicesEntry{podUID, conName, resource, devIds, allocResp})
 			}
 		}
 	}
@@ -160,7 +152,7 @@ func (pdev podDevices) toCheckpointData() []podDevicesCheckpointEntry {
 }
 
 // Populates podDevices from the passed in checkpointData.
-func (pdev podDevices) fromCheckpointData(data []podDevicesCheckpointEntry) {
+func (pdev podDevices) fromCheckpointData(data []checkpoint.PodDevicesEntry) {
 	for _, entry := range data {
 		glog.V(2).Infof("Get checkpoint entry: %v %v %v %v %v\n",
 			entry.PodUID, entry.ContainerName, entry.ResourceName, entry.DeviceIDs, entry.AllocResp)

pkg/kubelet/dockershim/BUILD

@@ -82,6 +82,8 @@ go_library(
         "//pkg/credentialprovider:go_default_library",
         "//pkg/kubelet/apis/cri/runtime/v1alpha2:go_default_library",
         "//pkg/kubelet/apis/kubeletconfig:go_default_library",
+        "//pkg/kubelet/checkpointmanager:go_default_library",
+        "//pkg/kubelet/checkpointmanager/checksum:go_default_library",
         "//pkg/kubelet/cm:go_default_library",
         "//pkg/kubelet/container:go_default_library",
         "//pkg/kubelet/dockershim/cm:go_default_library",
@@ -100,8 +102,6 @@ go_library(
         "//pkg/kubelet/util/ioutils:go_default_library",
         "//pkg/kubelet/util/store:go_default_library",
         "//pkg/security/apparmor:go_default_library",
-        "//pkg/util/filesystem:go_default_library",
-        "//pkg/util/hash:go_default_library",
         "//pkg/util/parsers:go_default_library",
         "//vendor/github.com/armon/circbuf:go_default_library",
         "//vendor/github.com/blang/semver:go_default_library",
@@ -149,6 +149,7 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//pkg/kubelet/apis/cri/runtime/v1alpha2:go_default_library",
+        "//pkg/kubelet/checkpointmanager:go_default_library",
         "//pkg/kubelet/container:go_default_library",
         "//pkg/kubelet/container/testing:go_default_library",
         "//pkg/kubelet/dockershim/libdocker:go_default_library",
@@ -186,7 +187,6 @@ filegroup(
         "//pkg/kubelet/dockershim/metrics:all-srcs",
         "//pkg/kubelet/dockershim/network:all-srcs",
         "//pkg/kubelet/dockershim/remote:all-srcs",
-        "//pkg/kubelet/dockershim/testing:all-srcs",
     ],
     tags = ["automanaged"],
     visibility = ["//visibility:public"],

pkg/kubelet/dockershim/convert.go

@@ -164,13 +164,14 @@ func containerToRuntimeAPISandbox(c *dockertypes.Container) (*runtimeapi.PodSand
 	}, nil
 }
 
-func checkpointToRuntimeAPISandbox(id string, checkpoint *PodSandboxCheckpoint) *runtimeapi.PodSandbox {
+func checkpointToRuntimeAPISandbox(id string, checkpoint DockershimCheckpoint) *runtimeapi.PodSandbox {
 	state := runtimeapi.PodSandboxState_SANDBOX_NOTREADY
+	_, name, namespace, _, _ := checkpoint.GetData()
 	return &runtimeapi.PodSandbox{
 		Id: id,
 		Metadata: &runtimeapi.PodSandboxMetadata{
-			Name:      checkpoint.Name,
-			Namespace: checkpoint.Namespace,
+			Name:      name,
+			Namespace: namespace,
 		},
 		State: state,
 	}

pkg/kubelet/dockershim/docker_checkpoint.go

@@ -18,14 +18,9 @@ package dockershim
 
 import (
 	"encoding/json"
-	"fmt"
-	"hash/fnv"
-	"path/filepath"
-
-	"github.com/golang/glog"
-	utilstore "k8s.io/kubernetes/pkg/kubelet/util/store"
-	utilfs "k8s.io/kubernetes/pkg/util/filesystem"
-	hashutil "k8s.io/kubernetes/pkg/util/hash"
+
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/checksum"
 )
 
 const (
@@ -36,6 +31,11 @@ const (
 	schemaVersion        = "v1"
 )
 
+type DockershimCheckpoint interface {
+	checkpointmanager.Checkpoint
+	GetData() (string, string, string, []*PortMapping, bool)
+}
+
 type Protocol string
 
 // PortMapping is the port mapping configurations of a sandbox.
@@ -65,89 +65,31 @@ type PodSandboxCheckpoint struct {
 	// Data to checkpoint for pod sandbox.
 	Data *CheckpointData `json:"data,omitempty"`
 	// Checksum is calculated with fnv hash of the checkpoint object with checksum field set to be zero
-	CheckSum uint64 `json:"checksum"`
-}
-
-// CheckpointHandler provides the interface to manage PodSandbox checkpoint
-type CheckpointHandler interface {
-	// CreateCheckpoint persists sandbox checkpoint in CheckpointStore.
-	CreateCheckpoint(podSandboxID string, checkpoint *PodSandboxCheckpoint) error
-	// GetCheckpoint retrieves sandbox checkpoint from CheckpointStore.
-	GetCheckpoint(podSandboxID string) (*PodSandboxCheckpoint, error)
-	// RemoveCheckpoint removes sandbox checkpoint form CheckpointStore.
-	// WARNING: RemoveCheckpoint will not return error if checkpoint does not exist.
-	RemoveCheckpoint(podSandboxID string) error
-	// ListCheckpoint returns the list of existing checkpoints.
-	ListCheckpoints() ([]string, error)
-}
-
-// PersistentCheckpointHandler is an implementation of CheckpointHandler. It persists checkpoint in CheckpointStore
-type PersistentCheckpointHandler struct {
-	store utilstore.Store
-}
-
-func NewPersistentCheckpointHandler(dockershimRootDir string) (CheckpointHandler, error) {
-	fstore, err := utilstore.NewFileStore(filepath.Join(dockershimRootDir, sandboxCheckpointDir), utilfs.DefaultFs{})
-	if err != nil {
-		return nil, err
-	}
-	return &PersistentCheckpointHandler{store: fstore}, nil
-}
-
-func (handler *PersistentCheckpointHandler) CreateCheckpoint(podSandboxID string, checkpoint *PodSandboxCheckpoint) error {
-	checkpoint.CheckSum = calculateChecksum(*checkpoint)
-	blob, err := json.Marshal(checkpoint)
-	if err != nil {
-		return err
-	}
-	return handler.store.Write(podSandboxID, blob)
+	Checksum checksum.Checksum `json:"checksum"`
 }
 
-func (handler *PersistentCheckpointHandler) GetCheckpoint(podSandboxID string) (*PodSandboxCheckpoint, error) {
-	blob, err := handler.store.Read(podSandboxID)
-	if err != nil {
-		return nil, err
-	}
-	var checkpoint PodSandboxCheckpoint
-	//TODO: unmarhsal into a struct with just Version, check version, unmarshal into versioned type.
-	err = json.Unmarshal(blob, &checkpoint)
-	if err != nil {
-		glog.Errorf("Failed to unmarshal checkpoint %q, removing checkpoint. Checkpoint content: %q. ErrMsg: %v", podSandboxID, string(blob), err)
-		handler.RemoveCheckpoint(podSandboxID)
-		return nil, fmt.Errorf("failed to unmarshal checkpoint")
-	}
-	if checkpoint.CheckSum != calculateChecksum(checkpoint) {
-		glog.Errorf("Checksum of checkpoint %q is not valid, removing checkpoint", podSandboxID)
-		handler.RemoveCheckpoint(podSandboxID)
-		return nil, fmt.Errorf("checkpoint is corrupted")
+func NewPodSandboxCheckpoint(namespace, name string, data *CheckpointData) DockershimCheckpoint {
+	return &PodSandboxCheckpoint{
+		Version:   schemaVersion,
+		Namespace: namespace,
+		Name:      name,
+		Data:      data,
 	}
-	return &checkpoint, nil
 }
 
-func (handler *PersistentCheckpointHandler) RemoveCheckpoint(podSandboxID string) error {
-	return handler.store.Delete(podSandboxID)
+func (cp *PodSandboxCheckpoint) MarshalCheckpoint() ([]byte, error) {
+	cp.Checksum = checksum.New(*cp.Data)
+	return json.Marshal(*cp)
 }
 
-func (handler *PersistentCheckpointHandler) ListCheckpoints() ([]string, error) {
-	keys, err := handler.store.List()
-	if err != nil {
-		return []string{}, fmt.Errorf("failed to list checkpoint store: %v", err)
-	}
-	return keys, nil
+func (cp *PodSandboxCheckpoint) UnmarshalCheckpoint(blob []byte) error {
+	return json.Unmarshal(blob, cp)
 }
 
-func NewPodSandboxCheckpoint(namespace, name string) *PodSandboxCheckpoint {
-	return &PodSandboxCheckpoint{
-		Version:   schemaVersion,
-		Namespace: namespace,
-		Name:      name,
-		Data:      &CheckpointData{},
-	}
+func (cp *PodSandboxCheckpoint) VerifyChecksum() error {
+	return cp.Checksum.Verify(*cp.Data)
 }
 
-func calculateChecksum(checkpoint PodSandboxCheckpoint) uint64 {
-	checkpoint.CheckSum = 0
-	hash := fnv.New32a()
-	hashutil.DeepHashObject(hash, checkpoint)
-	return uint64(hash.Sum32())
+func (cp *PodSandboxCheckpoint) GetData() (string, string, string, []*PortMapping, bool) {
+	return cp.Version, cp.Name, cp.Namespace, cp.Data.PortMappings, cp.Data.HostNetwork
 }

pkg/kubelet/dockershim/docker_checkpoint_test.go

@@ -17,86 +17,17 @@ limitations under the License.
 package dockershim
 
 import (
-	"sort"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-	utilstore "k8s.io/kubernetes/pkg/kubelet/dockershim/testing"
 )
 
-func NewTestPersistentCheckpointHandler() CheckpointHandler {
-	return &PersistentCheckpointHandler{store: utilstore.NewMemStore()}
-}
-
-func TestPersistentCheckpointHandler(t *testing.T) {
-	var err error
-	handler := NewTestPersistentCheckpointHandler()
-	port80 := int32(80)
-	port443 := int32(443)
-	proto := protocolTCP
-
-	checkpoint1 := NewPodSandboxCheckpoint("ns1", "sandbox1")
-	checkpoint1.Data.PortMappings = []*PortMapping{
-		{
-			&proto,
-			&port80,
-			&port80,
-		},
-		{
-			&proto,
-			&port443,
-			&port443,
-		},
-	}
-	checkpoint1.Data.HostNetwork = true
-
-	checkpoints := []struct {
-		podSandboxID      string
-		checkpoint        *PodSandboxCheckpoint
-		expectHostNetwork bool
-	}{
-		{
-			"id1",
-			checkpoint1,
-			true,
-		},
-		{
-			"id2",
-			NewPodSandboxCheckpoint("ns2", "sandbox2"),
-			false,
-		},
-	}
-
-	for _, tc := range checkpoints {
-		// Test CreateCheckpoints
-		err = handler.CreateCheckpoint(tc.podSandboxID, tc.checkpoint)
-		assert.NoError(t, err)
-
-		// Test GetCheckpoints
-		checkpoint, err := handler.GetCheckpoint(tc.podSandboxID)
-		assert.NoError(t, err)
-		assert.Equal(t, *checkpoint, *tc.checkpoint)
-		assert.Equal(t, checkpoint.Data.HostNetwork, tc.expectHostNetwork)
-	}
-	// Test ListCheckpoints
-	keys, err := handler.ListCheckpoints()
-	assert.NoError(t, err)
-	sort.Strings(keys)
-	assert.Equal(t, keys, []string{"id1", "id2"})
-
-	// Test RemoveCheckpoints
-	err = handler.RemoveCheckpoint("id1")
-	assert.NoError(t, err)
-	// Test Remove Nonexisted Checkpoints
-	err = handler.RemoveCheckpoint("id1")
-	assert.NoError(t, err)
-
-	// Test ListCheckpoints
-	keys, err = handler.ListCheckpoints()
-	assert.NoError(t, err)
-	assert.Equal(t, keys, []string{"id2"})
-
-	// Test Get NonExisted Checkpoint
-	_, err = handler.GetCheckpoint("id1")
-	assert.Error(t, err)
+func TestPodSandboxCheckpoint(t *testing.T) {
+	data := &CheckpointData{HostNetwork: true}
+	checkpoint := NewPodSandboxCheckpoint("ns1", "sandbox1", data)
+	version, name, namespace, _, hostNetwork := checkpoint.GetData()
+	assert.Equal(t, schemaVersion, version)
+	assert.Equal(t, "ns1", namespace)
+	assert.Equal(t, "sandbox1", name)
+	assert.Equal(t, true, hostNetwork)
 }

pkg/kubelet/dockershim/docker_sandbox.go

@@ -30,6 +30,7 @@ import (
 
 	utilerrors "k8s.io/apimachinery/pkg/util/errors"
 	runtimeapi "k8s.io/kubernetes/pkg/kubelet/apis/cri/runtime/v1alpha2"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager"
 	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
 	"k8s.io/kubernetes/pkg/kubelet/dockershim/libdocker"
 	"k8s.io/kubernetes/pkg/kubelet/qos"
@@ -118,7 +119,7 @@ func (ds *dockerService) RunPodSandbox(ctx context.Context, r *runtimeapi.RunPod
 	}(&err)
 
 	// Step 3: Create Sandbox Checkpoint.
-	if err = ds.checkpointHandler.CreateCheckpoint(createResp.ID, constructPodSandboxCheckpoint(config)); err != nil {
+	if err = ds.checkpointManager.CreateCheckpoint(createResp.ID, constructPodSandboxCheckpoint(config)); err != nil {
 		return nil, err
 	}
 
@@ -189,7 +190,8 @@ func (ds *dockerService) StopPodSandbox(ctx context.Context, r *runtimeapi.StopP
 		name = metadata.Name
 		hostNetwork = (networkNamespaceMode(inspectResult) == runtimeapi.NamespaceMode_NODE)
 	} else {
-		checkpoint, checkpointErr := ds.checkpointHandler.GetCheckpoint(podSandboxID)
+		checkpoint := NewPodSandboxCheckpoint("", "", &CheckpointData{})
+		checkpointErr := ds.checkpointManager.GetCheckpoint(podSandboxID, checkpoint)
 
 		// Proceed if both sandbox container and checkpoint could not be found. This means that following
 		// actions will only have sandbox ID and not have pod namespace and name information.
@@ -204,9 +206,7 @@ func (ds *dockerService) StopPodSandbox(ctx context.Context, r *runtimeapi.StopP
 					fmt.Errorf("failed to get sandbox status: %v", statusErr)})
 			}
 		} else {
-			namespace = checkpoint.Namespace
-			name = checkpoint.Name
-			hostNetwork = checkpoint.Data != nil && checkpoint.Data.HostNetwork
+			_, name, namespace, _, hostNetwork = checkpoint.GetData()
 		}
 	}
 
@@ -237,7 +237,7 @@ func (ds *dockerService) StopPodSandbox(ctx context.Context, r *runtimeapi.StopP
 			errList = append(errList, err)
 		} else {
 			// remove the checkpoint for any sandbox that is not found in the runtime
-			ds.checkpointHandler.RemoveCheckpoint(podSandboxID)
+			ds.checkpointManager.RemoveCheckpoint(podSandboxID)
 		}
 	}
 
@@ -284,7 +284,7 @@ func (ds *dockerService) RemovePodSandbox(ctx context.Context, r *runtimeapi.Rem
 	}
 
 	// Remove the checkpoint of the sandbox.
-	if err := ds.checkpointHandler.RemoveCheckpoint(podSandboxID); err != nil {
+	if err := ds.checkpointManager.RemoveCheckpoint(podSandboxID); err != nil {
 		errs = append(errs, err)
 	}
 	if len(errs) == 0 {
@@ -465,7 +465,7 @@ func (ds *dockerService) ListPodSandbox(_ context.Context, r *runtimeapi.ListPod
 	var err error
 	checkpoints := []string{}
 	if filter == nil {
-		checkpoints, err = ds.checkpointHandler.ListCheckpoints()
+		checkpoints, err = ds.checkpointManager.ListCheckpoints()
 		if err != nil {
 			glog.Errorf("Failed to list checkpoints: %v", err)
 		}
@@ -501,7 +501,8 @@ func (ds *dockerService) ListPodSandbox(_ context.Context, r *runtimeapi.ListPod
 		if _, ok := sandboxIDs[id]; ok {
 			continue
 		}
-		checkpoint, err := ds.checkpointHandler.GetCheckpoint(id)
+		checkpoint := NewPodSandboxCheckpoint("", "", &CheckpointData{})
+		err := ds.checkpointManager.GetCheckpoint(id, checkpoint)
 		if err != nil {
 			glog.Errorf("Failed to retrieve checkpoint for sandbox %q: %v", id, err)
 			continue
@@ -624,20 +625,20 @@ func ipcNamespaceMode(container *dockertypes.ContainerJSON) runtimeapi.Namespace
 	return runtimeapi.NamespaceMode_POD
 }
 
-func constructPodSandboxCheckpoint(config *runtimeapi.PodSandboxConfig) *PodSandboxCheckpoint {
-	checkpoint := NewPodSandboxCheckpoint(config.Metadata.Namespace, config.Metadata.Name)
+func constructPodSandboxCheckpoint(config *runtimeapi.PodSandboxConfig) checkpointmanager.Checkpoint {
+	data := CheckpointData{}
 	for _, pm := range config.GetPortMappings() {
 		proto := toCheckpointProtocol(pm.Protocol)
-		checkpoint.Data.PortMappings = append(checkpoint.Data.PortMappings, &PortMapping{
+		data.PortMappings = append(data.PortMappings, &PortMapping{
 			HostPort:      &pm.HostPort,
 			ContainerPort: &pm.ContainerPort,
 			Protocol:      &proto,
 		})
 	}
 	if config.GetLinux().GetSecurityContext().GetNamespaceOptions().GetNetwork() == runtimeapi.NamespaceMode_NODE {
-		checkpoint.Data.HostNetwork = true
+		data.HostNetwork = true
 	}
-	return checkpoint
+	return NewPodSandboxCheckpoint(config.Metadata.Namespace, config.Metadata.Name, &data)
 }
 
 func toCheckpointProtocol(protocol runtimeapi.Protocol) Protocol {

pkg/kubelet/dockershim/docker_service.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"path/filepath"
 	"sync"
 	"time"
 
@@ -30,6 +31,7 @@ import (
 	"k8s.io/api/core/v1"
 	runtimeapi "k8s.io/kubernetes/pkg/kubelet/apis/cri/runtime/v1alpha2"
 	"k8s.io/kubernetes/pkg/kubelet/apis/kubeletconfig"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager"
 	kubecm "k8s.io/kubernetes/pkg/kubelet/cm"
 	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
 	"k8s.io/kubernetes/pkg/kubelet/dockershim/cm"
@@ -191,7 +193,8 @@ func NewDockerService(config *ClientConfig, podSandboxImage string, streamingCon
 	client := NewDockerClientFromConfig(config)
 
 	c := libdocker.NewInstrumentedInterface(client)
-	checkpointHandler, err := NewPersistentCheckpointHandler(dockershimRootDir)
+
+	checkpointManager, err := checkpointmanager.NewCheckpointManager(filepath.Join(dockershimRootDir, sandboxCheckpointDir))
 	if err != nil {
 		return nil, err
 	}
@@ -205,7 +208,7 @@ func NewDockerService(config *ClientConfig, podSandboxImage string, streamingCon
 			execHandler: &NativeExecHandler{},
 		},
 		containerManager:  cm.NewContainerManager(cgroupsName, client),
-		checkpointHandler: checkpointHandler,
+		checkpointManager: checkpointManager,
 		disableSharedPID:  disableSharedPID,
 		networkReady:      make(map[string]bool),
 	}
@@ -293,7 +296,7 @@ type dockerService struct {
 	containerManager cm.ContainerManager
 	// cgroup driver used by Docker runtime.
 	cgroupDriver      string
-	checkpointHandler CheckpointHandler
+	checkpointManager checkpointmanager.CheckpointManager
 	// caches the version of the runtime.
 	// To be compatible with multiple docker versions, we need to perform
 	// version checking for some operations. Use this cache to avoid querying
@@ -365,7 +368,8 @@ func (ds *dockerService) GetNetNS(podSandboxID string) (string, error) {
 // GetPodPortMappings returns the port mappings of the given podSandbox ID.
 func (ds *dockerService) GetPodPortMappings(podSandboxID string) ([]*hostport.PortMapping, error) {
 	// TODO: get portmappings from docker labels for backward compatibility
-	checkpoint, err := ds.checkpointHandler.GetCheckpoint(podSandboxID)
+	checkpoint := NewPodSandboxCheckpoint("", "", &CheckpointData{})
+	err := ds.checkpointManager.GetCheckpoint(podSandboxID, checkpoint)
 	// Return empty portMappings if checkpoint is not found
 	if err != nil {
 		if err == utilstore.ErrKeyNotFound {
@@ -373,9 +377,9 @@ func (ds *dockerService) GetPodPortMappings(podSandboxID string) ([]*hostport.Po
 		}
 		return nil, err
 	}
-
-	portMappings := make([]*hostport.PortMapping, 0, len(checkpoint.Data.PortMappings))
-	for _, pm := range checkpoint.Data.PortMappings {
+	_, _, _, checkpointedPortMappings, _ := checkpoint.GetData()
+	portMappings := make([]*hostport.PortMapping, 0, len(checkpointedPortMappings))
+	for _, pm := range checkpointedPortMappings {
 		proto := toAPIProtocol(*pm.Protocol)
 		portMappings = append(portMappings, &hostport.PortMapping{
 			HostPort:      *pm.HostPort,

pkg/kubelet/dockershim/docker_service_test.go

@@ -30,6 +30,7 @@ import (
 
 	"k8s.io/apimachinery/pkg/util/clock"
 	runtimeapi "k8s.io/kubernetes/pkg/kubelet/apis/cri/runtime/v1alpha2"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager"
 	containertest "k8s.io/kubernetes/pkg/kubelet/container/testing"
 	"k8s.io/kubernetes/pkg/kubelet/dockershim/libdocker"
 	"k8s.io/kubernetes/pkg/kubelet/dockershim/network"
@@ -43,15 +44,50 @@ func newTestNetworkPlugin(t *testing.T) *nettest.MockNetworkPlugin {
 	return nettest.NewMockNetworkPlugin(ctrl)
 }
 
+type mockCheckpointManager struct {
+	checkpoint map[string]*PodSandboxCheckpoint
+}
+
+func (ckm *mockCheckpointManager) CreateCheckpoint(checkpointKey string, checkpoint checkpointmanager.Checkpoint) error {
+	ckm.checkpoint[checkpointKey] = checkpoint.(*PodSandboxCheckpoint)
+	return nil
+}
+
+func (ckm *mockCheckpointManager) GetCheckpoint(checkpointKey string, checkpoint checkpointmanager.Checkpoint) error {
+	*(checkpoint.(*PodSandboxCheckpoint)) = *(ckm.checkpoint[checkpointKey])
+	return nil
+}
+
+func (ckm *mockCheckpointManager) RemoveCheckpoint(checkpointKey string) error {
+	_, ok := ckm.checkpoint[checkpointKey]
+	if ok {
+		delete(ckm.checkpoint, "moo")
+	}
+	return nil
+}
+
+func (ckm *mockCheckpointManager) ListCheckpoints() ([]string, error) {
+	var keys []string
+	for key, _ := range ckm.checkpoint {
+		keys = append(keys, key)
+	}
+	return keys, nil
+}
+
+func newMockCheckpointManager() checkpointmanager.CheckpointManager {
+	return &mockCheckpointManager{checkpoint: make(map[string]*PodSandboxCheckpoint)}
+}
+
 func newTestDockerService() (*dockerService, *libdocker.FakeDockerClient, *clock.FakeClock) {
 	fakeClock := clock.NewFakeClock(time.Time{})
 	c := libdocker.NewFakeDockerClient().WithClock(fakeClock).WithVersion("1.11.2", "1.23").WithRandSource(rand.NewSource(0))
 	pm := network.NewPluginManager(&network.NoopNetworkPlugin{})
+	ckm := newMockCheckpointManager()
 	return &dockerService{
 		client:            c,
 		os:                &containertest.FakeOS{},
 		network:           pm,
-		checkpointHandler: NewTestPersistentCheckpointHandler(),
+		checkpointManager: ckm,
 		networkReady:      make(map[string]bool),
 	}, c, fakeClock
 }