Add health-check-monitor

cmd/healthchecker/health_checker.go

@@ -0,0 +1,57 @@
+/*
+Copyright 2020 The Kubernetes Authors All rights reserved.
+
+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 main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/spf13/pflag"
+
+	"k8s.io/node-problem-detector/cmd/healthchecker/options"
+	"k8s.io/node-problem-detector/pkg/custompluginmonitor/types"
+	"k8s.io/node-problem-detector/pkg/healthchecker"
+)
+
+func main() {
+	// Set glog flag so that it does not log to files.
+	if err := flag.Set("logtostderr", "true"); err != nil {
+		fmt.Printf("Failed to set logtostderr=true: %v", err)
+		os.Exit(int(types.Unknown))
+	}
+
+	hco := options.NewHealthCheckerOptions()
+	hco.AddFlags(pflag.CommandLine)
+	pflag.Parse()
+	hco.SetDefaults()
+	if err := hco.IsValid(); err != nil {
+		fmt.Println(err)
+		os.Exit(int(types.Unknown))
+	}
+
+	hc, err := healthchecker.NewHealthChecker(hco)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(int(types.Unknown))
+	}
+	if !hc.CheckHealth() {
+		fmt.Printf("%v:%v was found unhealthy; repair flag : %v\n", hco.Component, hco.SystemdService, hco.EnableRepair)
+		os.Exit(int(types.NonOK))
+	}
+	os.Exit(int(types.OK))
+}

cmd/healthchecker/options/options.go

@@ -0,0 +1,102 @@
+/*
+Copyright 2020 The Kubernetes Authors All rights reserved.
+
+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 options
+
+import (
+	"flag"
+	"fmt"
+	"time"
+
+	"github.com/spf13/pflag"
+
+	"k8s.io/node-problem-detector/pkg/healthchecker/types"
+)
+
+// NewHealthCheckerOptions returns an empty health check options struct.
+func NewHealthCheckerOptions() *HealthCheckerOptions {
+	return &HealthCheckerOptions{}
+}
+
+// HealthCheckerOptions are the options used to configure the health checker.
+type HealthCheckerOptions struct {
+	Component          string
+	SystemdService     string
+	EnableRepair       bool
+	CriCtlPath         string
+	CriSocketPath      string
+	CoolDownTime       time.Duration
+	HealthCheckTimeout time.Duration
+}
+
+// AddFlags adds health checker command line options to pflag.
+func (hco *HealthCheckerOptions) AddFlags(fs *pflag.FlagSet) {
+	fs.StringVar(&hco.Component, "component", types.KubeletComponent,
+		"The component to check health for. Supports kubelet, docker and cri")
+	fs.StringVar(&hco.SystemdService, "systemd-service", "",
+		"The underlying systemd service responsible for the component. Set to the corresponding component for docker and kubelet, containerd for cri.")
+	fs.BoolVar(&hco.EnableRepair, "enable-repair", true, "Flag to enable/disable repair attempt for the component.")
+	fs.StringVar(&hco.CriCtlPath, "crictl-path", types.DefaultCriCtl,
+		"The path to the crictl binary. This is used to check health of cri component.")
+	fs.StringVar(&hco.CriSocketPath, "cri-socket-path", types.DefaultCriSocketPath,
+		"The path to the cri socket. Used with crictl to specify the socket path.")
+	fs.DurationVar(&hco.CoolDownTime, "cooldown-time", types.DefaultCoolDownTime,
+		"The duration to wait for the service to be up before attempting repair.")
+	fs.DurationVar(&hco.HealthCheckTimeout, "health-check-timeout", types.DefaultHealthCheckTimeout,
+		"The time to wait before marking the component as unhealthy.")
+}
+
+// IsValid validates health checker command line options.
+// Returns error if invalid, nil otherwise.
+func (hco *HealthCheckerOptions) IsValid() error {
+	// Make sure the component specified is valid.
+	if hco.Component != types.KubeletComponent && hco.Component != types.DockerComponent && hco.Component != types.CRIComponent {
+		return fmt.Errorf("the component specified is not supported. Supported components are : <kubelet/docker/cri>")
+	}
+	// Make sure the systemd service is specified if repair is enabled.
+	if hco.EnableRepair && hco.SystemdService == "" {
+		return fmt.Errorf("systemd-service cannot be empty when repair is enabled")
+	}
+	// Skip checking further if the component is not cri.
+	if hco.Component != types.CRIComponent {
+		return nil
+	}
+	// Make sure the crictl path is not empty for cri component.
+	if hco.Component == types.CRIComponent && hco.CriCtlPath == "" {
+		return fmt.Errorf("the crictl-path cannot be empty for cri component")
+	}
+	// Make sure the cri socker path is not empty for cri component.
+	if hco.Component == types.CRIComponent && hco.CriSocketPath == "" {
+		return fmt.Errorf("the cri-socket-path cannot be empty for cri component")
+	}
+	return nil
+}
+
+// SetDefaults sets the defaults values for the dependent flags.
+func (hco *HealthCheckerOptions) SetDefaults() {
+	if hco.SystemdService != "" {
+		return
+	}
+	if hco.Component != types.CRIComponent {
+		hco.SystemdService = hco.Component
+		return
+	}
+	hco.SystemdService = types.ContainerdService
+}
+
+func init() {
+	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
+}

cmd/healthchecker/options/options_test.go

@@ -0,0 +1,76 @@
+/*
+Copyright 2020 The Kubernetes Authors All rights reserved.
+
+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 options
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"k8s.io/node-problem-detector/pkg/healthchecker/types"
+)
+
+func TestIsValid(t *testing.T) {
+	testCases := []struct {
+		name        string
+		hco         HealthCheckerOptions
+		expectError bool
+	}{
+		{
+			name: "valid component",
+			hco: HealthCheckerOptions{
+				Component: types.KubeletComponent,
+			},
+			expectError: false,
+		},
+		{
+			name: "invalid component",
+			hco: HealthCheckerOptions{
+				Component: "wrongComponent",
+			},
+			expectError: true,
+		},
+		{
+			name: "empty crictl-path with cri",
+			hco: HealthCheckerOptions{
+				Component:    types.CRIComponent,
+				CriCtlPath:   "",
+				EnableRepair: false,
+			},
+			expectError: true,
+		},
+		{
+			name: "empty systemd-service and repair enabled",
+			hco: HealthCheckerOptions{
+				Component:      types.KubeletComponent,
+				EnableRepair:   true,
+				SystemdService: "",
+			},
+			expectError: true,
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.name, func(t *testing.T) {
+			if test.expectError {
+				assert.Error(t, test.hco.IsValid(), "HealthChecker option %+v is invalid. Expected IsValid to return error.", test.hco)
+			} else {
+				assert.NoError(t, test.hco.IsValid(), "HealthChecker option %+v is valid. Expected IsValid to return nil.", test.hco)
+			}
+		})
+	}
+}