feat(container-kill): Adding the container-kill experiment (#50)

* feat(container-kill): Adding the container-kill experiment

Signed-off-by: shubhamchaudhary <shubham.chaudhary@mayadata.io>

* Update container-kill-k8s-job.yml

Co-authored-by: Karthik Satchitanand <karthik.s@mayadata.io>

Author: ispeakc0de

build/generate_go_binary

@@ -22,5 +22,7 @@ go build -o build/_output/kubelet-service-kill ./experiments/generic/kubelet-ser
 go build -o build/_output/node-memory-hog ./experiments/generic/node-memory-hog
 # Buiding go binaries for node_cpu_hog experiment
 go build -o build/_output/node-cpu-hog ./experiments/generic/node-cpu-hog
+# Buiding go binaries for container_kill experiment
+go build -o build/_output/container-kill ./experiments/generic/container-kill
 # Buiding go binaries for disk_fill experiment
-go build -o build/_output/disk-fill ./experiments/generic/disk-fill
+go build -o build/_output/disk-fill ./experiments/generic/disk-fill

chaoslib/litmus/container_kill/container-kill.go

@@ -0,0 +1,373 @@
+package container_kill
+
+import (
+	"math/rand"
+	"strconv"
+	"time"
+
+	clients "github.com/litmuschaos/litmus-go/pkg/clients"
+	experimentTypes "github.com/litmuschaos/litmus-go/pkg/generic/container-kill/types"
+	"github.com/litmuschaos/litmus-go/pkg/log"
+	"github.com/litmuschaos/litmus-go/pkg/math"
+	"github.com/litmuschaos/litmus-go/pkg/status"
+	"github.com/litmuschaos/litmus-go/pkg/types"
+	"github.com/openebs/maya/pkg/util/retry"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	apiv1 "k8s.io/api/core/v1"
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+//PrepareContainerKill contains the prepration steps before chaos injection
+func PrepareContainerKill(experimentsDetails *experimentTypes.ExperimentDetails, clients clients.ClientSets, resultDetails *types.ResultDetails, eventsDetails *types.EventDetails) error {
+
+	//Select application pod and node name for the container-kill
+	appName, appNodeName, err := GetApplicationPod(experimentsDetails, clients)
+	if err != nil {
+		return errors.Errorf("Unable to get the application name and application nodename due to, err: %v", err)
+	}
+
+	//Get the target container name of the application pod
+	if experimentsDetails.TargetContainer == "" {
+		experimentsDetails.TargetContainer, err = GetTargetContainer(experimentsDetails, appName, clients)
+		if err != nil {
+			return errors.Errorf("Unable to get the target container name due to, err: %v", err)
+		}
+	}
+
+	log.InfoWithValues("[Info]: Details of application under chaos injection", logrus.Fields{
+		"PodName":       appName,
+		"NodeName":      appNodeName,
+		"ContainerName": experimentsDetails.TargetContainer,
+	})
+
+	//Getting the iteration count for the container-kill
+	GetIterations(experimentsDetails)
+
+	// generating a unique string which can be appended with the helper pod name & labels for the uniquely identification
+	experimentsDetails.RunID = GetRunID()
+
+	// Getting the serviceAccountName, need permission inside helper pod to create the events
+	if experimentsDetails.ChaosServiceAccount == "" {
+		err = GetServiceAccount(experimentsDetails, clients)
+		if err != nil {
+			return errors.Errorf("Unable to get the serviceAccountName, err: %v", err)
+		}
+	}
+
+	//Waiting for the ramp time before chaos injection
+	if experimentsDetails.RampTime != 0 {
+		log.Infof("[Ramp]: Waiting for the %vs ramp time before injecting chaos", strconv.Itoa(experimentsDetails.RampTime))
+		waitForDuration(experimentsDetails.RampTime)
+	}
+
+	//GetRestartCount return the restart count of target container
+	restartCountBefore, err := GetRestartCount(experimentsDetails, appName, clients)
+	if err != nil {
+		return err
+	}
+
+	log.Infof("restartCount of target container before chaos injection: %v", strconv.Itoa(restartCountBefore))
+
+	// creating the helper pod to perform container kill chaos
+	err = CreateHelperPod(experimentsDetails, clients, appName, appNodeName)
+	if err != nil {
+		return errors.Errorf("Unable to create the helper pod, err: %v", err)
+	}
+
+	//checking the status of the helper pod, wait till the helper pod comes to running state else fail the experiment
+	log.Info("[Status]: Checking the status of the helper pod")
+	err = status.CheckApplicationStatus(experimentsDetails.ChaosNamespace, "name=container-kill-"+experimentsDetails.RunID, clients)
+	if err != nil {
+		return errors.Errorf("helper pod is not in running state, err: %v", err)
+	}
+
+	// Recording the chaos start timestamp
+	ChaosStartTimeStamp := time.Now().Unix()
+
+	// Wait till the completion of the helper pod
+	// set an upper limit for the waiting time
+	log.Info("[Wait]: waiting till the completion of the helper pod")
+	err = status.WaitForCompletion(experimentsDetails.ChaosNamespace, "name=container-kill-"+experimentsDetails.RunID, clients, experimentsDetails.ChaosDuration+experimentsDetails.ChaosInterval+60)
+	if err != nil {
+		return err
+	}
+
+	//ChaosCurrentTimeStamp contains the current timestamp
+	ChaosCurrentTimeStamp := time.Now().Unix()
+	//ChaosDiffTimeStamp contains the difference of current timestamp and start timestamp
+	//It will helpful to track the total chaos duration
+	chaosDiffTimeStamp := ChaosCurrentTimeStamp - ChaosStartTimeStamp
+
+	if int(chaosDiffTimeStamp) < experimentsDetails.ChaosDuration {
+		return errors.Errorf("The helper pod failed, check the logs of helper pod for more details")
+	}
+
+	//Deleting the helper pod for container-kill chaos
+	log.Info("[Cleanup]: Deleting the helper pod")
+	err = DeleteHelperPod(experimentsDetails, clients)
+	if err != nil {
+		return errors.Errorf("Unable to delete the helper pod, err: %v", err)
+	}
+
+	// It will verify that the restart count of container should increase after chaos injection
+	err = VerifyRestartCount(experimentsDetails, appName, clients, restartCountBefore)
+	if err != nil {
+		return errors.Errorf("Target container is not restarted , err: %v", err)
+	}
+
+	//Waiting for the ramp time after chaos injection
+	if experimentsDetails.RampTime != 0 {
+		log.Infof("[Ramp]: Waiting for the %vs ramp time after injecting chaos", strconv.Itoa(experimentsDetails.RampTime))
+		waitForDuration(experimentsDetails.RampTime)
+	}
+	return nil
+}
+
+//GetIterations derive the iterations value from given parameters
+func GetIterations(experimentsDetails *experimentTypes.ExperimentDetails) {
+	var Iterations int
+	if experimentsDetails.ChaosInterval != 0 {
+		Iterations = experimentsDetails.ChaosDuration / experimentsDetails.ChaosInterval
+	}
+	experimentsDetails.Iterations = math.Maximum(Iterations, 1)
+
+}
+
+//waitForDuration waits for the given time duration (in seconds)
+func waitForDuration(duration int) {
+	time.Sleep(time.Duration(duration) * time.Second)
+}
+
+// GetRunID generate a random string
+func GetRunID() string {
+	var letterRunes = []rune("abcdefghijklmnopqrstuvwxyz")
+	runID := make([]rune, 6)
+	for i := range runID {
+		runID[i] = letterRunes[rand.Intn(len(letterRunes))]
+	}
+	return string(runID)
+}
+
+// GetServiceAccount find the serviceAccountName for the helper pod
+func GetServiceAccount(experimentsDetails *experimentTypes.ExperimentDetails, clients clients.ClientSets) error {
+	pod, err := clients.KubeClient.CoreV1().Pods(experimentsDetails.ChaosNamespace).Get(experimentsDetails.ChaosPodName, v1.GetOptions{})
+	if err != nil {
+		return err
+	}
+	experimentsDetails.ChaosServiceAccount = pod.Spec.ServiceAccountName
+	return nil
+}
+
+//GetApplicationPod will select a random replica of application pod for chaos
+//It will also get the node name of the application pod
+func GetApplicationPod(experimentsDetails *experimentTypes.ExperimentDetails, clients clients.ClientSets) (string, string, error) {
+	podList, err := clients.KubeClient.CoreV1().Pods(experimentsDetails.AppNS).List(v1.ListOptions{LabelSelector: experimentsDetails.AppLabel})
+	if err != nil || len(podList.Items) == 0 {
+		return "", "", errors.Wrapf(err, "Fail to get the application pod in %v namespace", experimentsDetails.AppNS)
+	}
+
+	rand.Seed(time.Now().Unix())
+	randomIndex := rand.Intn(len(podList.Items))
+	applicationName := podList.Items[randomIndex].Name
+	nodeName := podList.Items[randomIndex].Spec.NodeName
+
+	return applicationName, nodeName, nil
+}
+
+//GetRestartCount return the restart count of target container
+func GetRestartCount(experimentsDetails *experimentTypes.ExperimentDetails, podName string, clients clients.ClientSets) (int, error) {
+	pod, err := clients.KubeClient.CoreV1().Pods(experimentsDetails.AppNS).Get(podName, v1.GetOptions{})
+	if err != nil {
+		return 0, err
+	}
+	restartCount := 0
+	for _, container := range pod.Status.ContainerStatuses {
+		if container.Name == experimentsDetails.TargetContainer {
+			restartCount = int(container.RestartCount)
+			break
+		}
+	}
+	return restartCount, nil
+}
+
+//VerifyRestartCount verify the restart count of target container that it is restarted or not after chaos injection
+func VerifyRestartCount(experimentsDetails *experimentTypes.ExperimentDetails, podName string, clients clients.ClientSets, restartCountBefore int) error {
+
+	restartCountAfter := 0
+	err := retry.
+		Times(90).
+		Wait(1 * time.Second).
+		Try(func(attempt uint) error {
+			pod, err := clients.KubeClient.CoreV1().Pods(experimentsDetails.AppNS).Get(podName, v1.GetOptions{})
+			if err != nil {
+				return errors.Errorf("Unable to get the application pod, err: %v", err)
+			}
+			for _, container := range pod.Status.ContainerStatuses {
+				if container.Name == experimentsDetails.TargetContainer {
+					restartCountAfter = int(container.RestartCount)
+					break
+				}
+			}
+			if restartCountAfter <= restartCountBefore {
+				return errors.Errorf("Target container is not restarted")
+			}
+			return nil
+		})
+
+	log.Infof("restartCount of target container after chaos injection: %v", strconv.Itoa(restartCountAfter))
+
+	return err
+
+}
+
+//GetTargetContainer will fetch the conatiner name from application pod
+//This container will be used as target container
+func GetTargetContainer(experimentsDetails *experimentTypes.ExperimentDetails, appName string, clients clients.ClientSets) (string, error) {
+	pod, err := clients.KubeClient.CoreV1().Pods(experimentsDetails.AppNS).Get(appName, v1.GetOptions{})
+	if err != nil {
+		return "", errors.Wrapf(err, "Fail to get the application pod status, due to:%v", err)
+	}
+
+	return pod.Spec.Containers[0].Name, nil
+}
+
+// CreateHelperPod derive the attributes for helper pod and create the helper pod
+func CreateHelperPod(experimentsDetails *experimentTypes.ExperimentDetails, clients clients.ClientSets, podName, nodeName string) error {
+
+	privilegedEnable := true
+
+	helperPod := &apiv1.Pod{
+		ObjectMeta: v1.ObjectMeta{
+			Name:      "container-kill-" + experimentsDetails.RunID,
+			Namespace: experimentsDetails.ChaosNamespace,
+			Labels: map[string]string{
+				"app":      "container-kill",
+				"name":     "container-kill-" + experimentsDetails.RunID,
+				"chaosUID": string(experimentsDetails.ChaosUID),
+			},
+		},
+		Spec: apiv1.PodSpec{
+			ServiceAccountName: experimentsDetails.ChaosServiceAccount,
+			RestartPolicy:      apiv1.RestartPolicyNever,
+			NodeName:           nodeName,
+			Volumes: []apiv1.Volume{
+				{
+					Name: "cri-socket",
+					VolumeSource: apiv1.VolumeSource{
+						HostPath: &apiv1.HostPathVolumeSource{
+							Path: experimentsDetails.ContainerPath,
+						},
+					},
+				},
+				{
+					Name: "cri-config",
+					VolumeSource: apiv1.VolumeSource{
+						HostPath: &apiv1.HostPathVolumeSource{
+							Path: "/etc/crictl.yaml",
+						},
+					},
+				},
+			},
+			Containers: []apiv1.Container{
+				{
+					Name:            "container-kill",
+					Image:           experimentsDetails.LIBImage,
+					ImagePullPolicy: apiv1.PullAlways,
+					Command: []string{
+						"bin/bash",
+					},
+					Args: []string{
+						"-c",
+						"./experiments/container-kill",
+					},
+					Env: GetPodEnv(experimentsDetails, podName),
+					VolumeMounts: []apiv1.VolumeMount{
+						{
+							Name:      "cri-socket",
+							MountPath: experimentsDetails.ContainerPath,
+						},
+						{
+							Name:      "cri-config",
+							MountPath: "/etc/crictl.yaml",
+						},
+					},
+					SecurityContext: &apiv1.SecurityContext{
+						Privileged: &privilegedEnable,
+					},
+				},
+			},
+		},
+	}
+
+	_, err := clients.KubeClient.CoreV1().Pods(experimentsDetails.ChaosNamespace).Create(helperPod)
+	return err
+
+}
+
+//DeleteHelperPod deletes the helper pod and wait until it got terminated
+func DeleteHelperPod(experimentsDetails *experimentTypes.ExperimentDetails, clients clients.ClientSets) error {
+
+	err := clients.KubeClient.CoreV1().Pods(experimentsDetails.ChaosNamespace).Delete("container-kill-"+experimentsDetails.RunID, &v1.DeleteOptions{})
+
+	if err != nil {
+		return err
+	}
+
+	// waiting for the termination of the pod
+	err = retry.
+		Times(90).
+		Wait(1 * time.Second).
+		Try(func(attempt uint) error {
+			podSpec, err := clients.KubeClient.CoreV1().Pods(experimentsDetails.ChaosNamespace).List(v1.ListOptions{LabelSelector: "name=container-kill-" + experimentsDetails.RunID})
+			if err != nil || len(podSpec.Items) != 0 {
+				return errors.Errorf("Pod is not deleted yet, err: %v", err)
+			}
+			return nil
+		})
+
+	return err
+}
+
+// GetPodEnv derive all the env required for the helper pod
+func GetPodEnv(experimentsDetails *experimentTypes.ExperimentDetails, podName string) []apiv1.EnvVar {
+
+	var envVar []apiv1.EnvVar
+	ENVList := map[string]string{
+		"APP_NS":               experimentsDetails.AppNS,
+		"APP_POD":              podName,
+		"APP_CONTAINER":        experimentsDetails.TargetContainer,
+		"TOTAL_CHAOS_DURATION": strconv.Itoa(experimentsDetails.ChaosDuration),
+		"CHAOS_NAMESPACE":      experimentsDetails.ChaosNamespace,
+		"CHAOS_ENGINE":         experimentsDetails.EngineName,
+		"CHAOS_UID":            string(experimentsDetails.ChaosUID),
+		"CHAOS_INTERVAL":       strconv.Itoa(experimentsDetails.ChaosInterval),
+		"ITERATIONS":           strconv.Itoa(experimentsDetails.Iterations),
+	}
+	for key, value := range ENVList {
+		var perEnv apiv1.EnvVar
+		perEnv.Name = key
+		perEnv.Value = value
+		envVar = append(envVar, perEnv)
+	}
+	// Getting experiment pod name from downward API
+	experimentPodName := GetValueFromDownwardAPI("v1", "metadata.name")
+
+	var downwardEnv apiv1.EnvVar
+	downwardEnv.Name = "POD_NAME"
+	downwardEnv.ValueFrom = &experimentPodName
+	envVar = append(envVar, downwardEnv)
+
+	return envVar
+}
+
+// GetValueFromDownwardAPI returns the value from downwardApi
+func GetValueFromDownwardAPI(apiVersion string, fieldPath string) apiv1.EnvVarSource {
+	downwardENV := apiv1.EnvVarSource{
+		FieldRef: &apiv1.ObjectFieldSelector{
+			APIVersion: apiVersion,
+			FieldPath:  fieldPath,
+		},
+	}
+	return downwardENV
+}