|Type||Description||Tested K8s Platform|
|Generic||Inject Network Latency Into Application Pod||GKE, Packet(Kubeadm), EKS, Minikube > v1.6.0, AKS|
- Ensure that the Litmus Chaos Operator is running by executing
kubectl get podsin operator namespace (typically,
litmus). If not, install from here
- Ensure that the
pod-network-latencyexperiment resource is available in the cluster by executing kubectl
get chaosexperimentsin the desired namespace. . If not, install from here
- Application pods are healthy before chaos injection
- Application pods are healthy post chaos injection
- The application pod should be healthy once chaos is stopped. Service-requests should be served despite chaos.
- Causes flaky access to application replica by injecting network delay using pumba.
- Injects latency on the specified container by starting a traffic control (tc) process with netem rules to add egress delays
- Latency is injected via pumba library with command pumba netem delay by passing the relevant network interface, latency, chaos duration and regex filter for container name
- Can test the application's resilience to lossy/flaky network
Steps to Execute the Chaos Experiment
This Chaos Experiment can be triggered by creating a ChaosEngine resource on the cluster. To understand the values to provide in a ChaosEngine specification, refer Getting Started
Follow the steps in the sections below to create the chaosServiceAccount, prepare the ChaosEngine & execute the experiment.
- Use this sample RBAC manifest to create a chaosServiceAccount in the desired (app) namespace. This example consists of the minimum necessary role permissions to execute the experiment.
Sample Rbac Manifest
apiVersion: v1 kind: ServiceAccount metadata: name: pod-network-latency-sa namespace: default labels: name: pod-network-latency-sa apiVersion: rbac.authorization.k8s.io/v1beta1 kind: Role metadata: name: pod-network-latency-sa namespace: default labels: name: pod-network-latency-sa rules: - apiGroups: ["","litmuschaos.io","batch"] resources: ["pods","jobs","pods/log","events","chaosengines","chaosexperiments","chaosresults"] verbs: ["create","list","get","patch","update","delete","deletecollection"] apiVersion: rbac.authorization.k8s.io/v1beta1 kind: RoleBinding metadata: name: pod-network-latency-sa namespace: default labels: name: pod-network-latency-sa roleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: pod-network-latency-sa subjects: - kind: ServiceAccount name: pod-network-latency-sa namespace: default
- Provide the application info in
- Override the experiment tunables if desired in
- To understand the values to provided in a ChaosEngine specification, refer ChaosEngine Concepts
Supported Experiment Tunables
|NETWORK_INTERFACE||Name of ethernet interface considered for shaping traffic||Mandatory|
|TARGET_CONTAINER||Name of container which is subjected to network latency||Mandatory|
|NETWORK_LATENCY||The latency/delay in milliseconds||Optional||Default (60000ms)|
|TOTAL_CHAOS_DURATION||The time duration for chaos insertion (seconds)||Optional||Default (60s)|
|TARGET_POD||Name of the application pod subjected to pod network latency chaos||Optional||If not provided it will select from the app label provided|
|PODS_AFFECTED_PERC||The Percentage of total pods to target||Optional||Defaults to 0% (corresponds to 1 replica)|
|CONTAINER_RUNTIME||container runtime interface for the cluster||Optional||Defaults to docker, supported values: docker, containerd, crio|
|SOCKET_PATH||Path of the containerd/crio socket file||Optional||Defaults to `/run/containerd/containerd.sock`|
|LIB||The chaos lib used to inject the chaos||Optional||Defaults to litmus, only litmus supported|
|TC_IMAGE||Image used for traffic control in linux||Optional||default value is `gaiadocker/iproute2`|
|LIB_IMAGE||Image used to run the netem command||Optional||Defaults to `litmuschaos/go-runner:latest`|
|RAMP_TIME||Period to wait before and after injection of chaos in sec||Optional|
|INSTANCE_ID||A user-defined string that holds metadata/info about current run/instance of chaos. Ex: 04-05-2020-9-00. This string is appended as suffix in the chaosresult CR name.||Ensure that the overall length of the chaosresult CR is still < 64 characters|
Sample ChaosEngine Manifest
apiVersion: litmuschaos.io/v1alpha1 kind: ChaosEngine metadata: name: nginx-network-chaos namespace: default spec: # It can be delete/retain jobCleanUpPolicy: 'delete' # It can be true/false annotationCheck: 'true' # It can be active/stop engineState: 'active' #ex. values: ns1:name=percona,ns2:run=nginx auxiliaryAppInfo: '' monitoring: false appinfo: appns: 'default' # FYI, To see app label, apply kubectl get pods --show-labels applabel: 'app=nginx' appkind: 'deployment' chaosServiceAccount: pod-network-latency-sa experiments: - name: pod-network-latency spec: components: env: #Container name where chaos has to be injected - name: TARGET_CONTAINER value: 'nginx' #Network interface inside target container - name: NETWORK_INTERFACE value: 'eth0' - name: LIB_IMAGE value: 'litmuschaos/go-runner:latest' - name: NETWORK_LATENCY value: '60000' - name: TOTAL_CHAOS_DURATION value: '60' # in seconds # provide the name of container runtime # it supports docker, containerd, crio # default to docker - name: CONTAINER_RUNTIME value: 'docker' # provide the socket file path # applicable only for containerd and crio runtime - name: SOCKET_PATH value: '/run/containerd/containerd.sock'
Create the ChaosEngine Resource
Create the ChaosEngine manifest prepared in the previous step to trigger the Chaos.
kubectl apply -f chaosengine.yml
If the chaos experiment is not executed, refer to the troubleshooting section to identify the root cause and fix the issues.
Watch Chaos progress
View network latency by setting up a ping on the affected pod from the cluster nodes
Check Chaos Experiment Result
Check whether the application is resilient to the Pod Network Latency, once the experiment (job) is completed. The ChaosResult resource name is derived like this:
kubectl describe chaosresult <ChaosEngine-Name>-<ChaosExperiment-Name> -n <application-namespace>
Application Pod Network Latency Demo
- A sample recording of this experiment execution is provided here.