Pod Network Rate Limit

Introduction

• It injects rate limiting on the specified container by starting a traffic control (tc) process using tbf (Token Bucket Filtering) algorithm
• It can test the application's resilience to limited network bandwidth

Scenario: Induce network rate limit of the target pod

Uses

View the uses of the experiment

coming soon

Prerequisites

Verify the prerequisites

• Ensure that Kubernetes Version > 1.16
• Ensure that the Litmus Chaos Operator is running by executing kubectl get pods in operator namespace (typically, litmus).If not, install from here
• Ensure that the pod-network-rate-limit experiment resource is available in the cluster by executing kubectl get chaosexperiments in the desired namespace. If not, install from here

Default Validations

View the default validations

The application pods should be in running state before and after chaos injection.

Minimal RBAC configuration example (optional)

NOTE

If you are using this experiment as part of a litmus workflow scheduled constructed & executed from chaos-center, then you may be making use of the litmus-admin RBAC, which is pre installed in the cluster as part of the agent setup.

View the Minimal RBAC permissions

apiVersion: v1
kind: ServiceAccount
metadata:
  name: pod-network-rate-limit-sa
  namespace: default
  labels:
    name: pod-network-rate-limit-sa
    app.kubernetes.io/part-of: litmus
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: pod-network-rate-limit-sa
  namespace: default
  labels:
    name: pod-network-rate-limit-sa
    app.kubernetes.io/part-of: litmus
rules:
  # Create and monitor the experiment & helper pods
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["create","delete","get","list","patch","update", "deletecollection"]
  # Performs CRUD operations on the events inside chaosengine and chaosresult
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["create","get","list","patch","update"]
  # Fetch configmaps details and mount it to the experiment pod (if specified)
  - apiGroups: [""]
    resources: ["configmaps"]
    verbs: ["get","list",]
  # Track and get the runner, experiment, and helper pods log
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["get","list","watch"]
  # for creating and managing to execute comands inside target container
  - apiGroups: [""]
    resources: ["pods/exec"]
    verbs: ["get","list","create"]
  # deriving the parent/owner details of the pod(if parent is anyof {deployment, statefulset, daemonsets})
  - apiGroups: ["apps"]
    resources: ["deployments","statefulsets","replicasets", "daemonsets"]
    verbs: ["list","get"]
  # deriving the parent/owner details of the pod(if parent is deploymentConfig)
  - apiGroups: ["apps.openshift.io"]
    resources: ["deploymentconfigs"]
    verbs: ["list","get"]
  # deriving the parent/owner details of the pod(if parent is deploymentConfig)
  - apiGroups: [""]
    resources: ["replicationcontrollers"]
    verbs: ["get","list"]
  # deriving the parent/owner details of the pod(if parent is argo-rollouts)
  - apiGroups: ["argoproj.io"]
    resources: ["rollouts"]
    verbs: ["list","get"]
  # for configuring and monitor the experiment job by the chaos-runner pod
  - apiGroups: ["batch"]
    resources: ["jobs"]
    verbs: ["create","list","get","delete","deletecollection"]
  # for creation, status polling and deletion of litmus chaos resources used within a chaos workflow
  - apiGroups: ["litmuschaos.io"]
    resources: ["chaosengines","chaosexperiments","chaosresults"]
    verbs: ["create","list","get","patch","update","delete"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: pod-network-rate-limit-sa
  namespace: default
  labels:
    name: pod-network-rate-limit-sa
    app.kubernetes.io/part-of: litmus
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: pod-network-rate-limit-sa
subjects:
- kind: ServiceAccount
  name: pod-network-rate-limit-sa
  namespace: default

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.

Experiment tunables

check the experiment tunables

Optional Fields

Variables	Description	Notes
NETWORK_INTERFACE	Name of ethernet interface considered for shaping traffic
TARGET_CONTAINER	Name of container which is subjected to network rate limit	Optional	If the value is not provided, it injects chaos on the first container of the pod
NETWORK_BANDWIDTH	Specify the network bandwidth rate limit	For more information, go to rate limit.
BURST	Specify the burst for the size of bucket, maximum amount of bytes that tokens can be available for instantaneously	For more information, go to rate limit.
LIMIT	Specify the limit for the number of bytes that can be queued waiting for tokens to become available	For more information, go to rate limit.
MIN_BURST	Specify the size of the peakrate bucket
PEAK_RATE	Specify the maximum depletion rate of the bucket
CONTAINER_RUNTIME	container runtime interface for the cluster	Defaults to containerd, supported values: docker, containerd and crio
SOCKET_PATH	Path of the containerd/crio/docker socket file	Defaults to /run/containerd/containerd.sock
TOTAL_CHAOS_DURATION	The time duration for chaos insertion (seconds)	Default (60s)
TARGET_PODS	Comma separated list of application pod name subjected to pod network corruption chaos	If not provided, it will select target pods randomly based on provided appLabels
DESTINATION_IPS	IP addresses of the services or pods or the CIDR blocks(range of IPs), the accessibility to which is impacted	comma separated IP(S) or CIDR(S) can be provided. if not provided, it will induce network chaos for all ips/destinations
DESTINATION_HOSTS	DNS Names/FQDN names of the services, the accessibility to which, is impacted	if not provided, it will induce network chaos for all ips/destinations or DESTINATION_IPS if already defined
SOURCE_PORTS	ports of the target application, the accessibility to which is impacted	comma separated port(s) can be provided. If not provided, it will induce network chaos for all ports
DESTINATION_PORTS	ports of the destination services or pods or the CIDR blocks(range of IPs), the accessibility to which is impacted	comma separated port(s) can be provided. If not provided, it will induce network chaos for all ports
PODS_AFFECTED_PERC	The Percentage of total pods to target	Defaults to 0 (corresponds to 1 replica), provide numeric value only
LIB_IMAGE	Image used to run the netem command	Defaults to litmuschaos/go-runner:latest
RAMP_TIME	Period to wait before and after injection of chaos in sec
SEQUENCE	It defines sequence of chaos execution for multiple target pods	Default value: parallel. Supported: serial, parallel

Experiment Examples

Common and Pod specific tunables

Refer the common attributes and Pod specific tunable to tune the common tunables for all experiments and pod specific tunables.

Rate Limit

It defines the network bandwidth rate limit to be applied to the targeted application. It can be tuned via NETWORK_BANDWIDTH ENV along with BURST and LIMIT parameters.

• NETWORK_BANDWIDTH: Specify the network bandwidth rate limit (e.g., '1mbit', '100kbit')
• BURST: Specify the burst for the size of bucket, maximum amount of bytes that tokens can be available for instantaneously
• LIMIT: Specify the limit for the number of bytes that can be queued waiting for tokens to become available

Use the following example to tune this:

# it applies rate limiting to the egress traffic
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-network-rate-limit-sa
  experiments:
  - name: pod-network-rate-limit
    spec:
      components:
        env:
        # network bandwidth rate limit
        - name: NETWORK_BANDWIDTH
          value: '1mbit'
        # burst size for the bucket
        - name: BURST
          value: '32kbit'
        # limit for bytes that can be queued
        - name: LIMIT
          value: '1600'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Destination IPs And Destination Hosts

The network experiments interrupt traffic for all the IPs/hosts by default. The interruption of specific IPs/Hosts can be tuned via DESTINATION_IPS and DESTINATION_HOSTS ENV.

• DESTINATION_IPS: It contains the IP addresses of the services or pods or the CIDR blocks(range of IPs), the accessibility to which is impacted.
• DESTINATION_HOSTS: It contains the DNS Names/FQDN names of the services, the accessibility to which, is impacted.

Use the following example to tune this:

# it inject the chaos for the egress traffic for specific ips/hosts
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-network-rate-limit-sa
  experiments:
  - name: pod-network-rate-limit
    spec:
      components:
        env:
        # supports comma separated destination ips
        - name: DESTINATION_IPS
          value: '8.8.8.8,192.168.5.6'
        # supports comma separated destination hosts
        - name: DESTINATION_HOSTS
          value: 'nginx.default.svc.cluster.local,google.com'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Source And Destination Ports

The network experiments interrupt traffic for all the source & destination ports by default. The interruption of specific port(s) can be tuned via SOURCE_PORTS and DESTINATION_PORTS ENV.

• SOURCE_PORTS: It contains ports of the target application, the accessibility to which is impacted
• DESTINATION_PORTS: It contains the ports of the destination services or pods or the CIDR blocks(range of IPs), the accessibility to which is impacted

Use the following example to tune this:

# it inject the chaos for the ingrees and egress traffic for specific ports
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-network-rate-limit-sa
  experiments:
  - name: pod-network-rate-limit
    spec:
      components:
        env:
        # supports comma separated source ports
        - name: SOURCE_PORTS
          value: '80'
        # supports comma separated destination ports
        - name: DESTINATION_PORTS
          value: '8080,9000'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Blacklist Source and Destination Ports

By default, the network experiments disrupt traffic for all the source and destination ports. The specific ports can be blacklisted via SOURCE_PORTS and DESTINATION_PORTS ENV.

• SOURCE_PORTS: Provide the comma separated source ports preceded by !, that you'd like to blacklist from the chaos.
• DESTINATION_PORTS: Provide the comma separated destination ports preceded by ! , that you'd like to blacklist from the chaos.

Use the following example to tune this:

# blacklist the source and destination ports
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-network-rate-limit-sa
  experiments:
  - name: pod-network-rate-limit
    spec:
      components:
        env:
        # it will blacklist 80 and 8080 source ports
        - name: SOURCE_PORTS
          value: '!80,8080'
        # it will blacklist 8080 and 9000 destination ports
        - name: DESTINATION_PORTS
          value: '!8080,9000'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Network Interface

The defined name of the ethernet interface, which is considered for shaping traffic. It can be tuned via NETWORK_INTERFACE ENV. Its default value is eth0.

Use the following example to tune this:

# provide the network interface
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-network-rate-limit-sa
  experiments:
  - name: pod-network-rate-limit
    spec:
      components:
        env:
        # name of the network interface
        - name: NETWORK_INTERFACE
          value: 'eth0'
        - name: TOTAL_CHAOS_DURATION
          value: '60'

Container Runtime Socket Path

It defines the CONTAINER_RUNTIME and SOCKET_PATH ENV to set the container runtime and socket file path.

• CONTAINER_RUNTIME: It supports docker, containerd, and crio runtimes. The default value is docker.
• SOCKET_PATH: It contains path of docker socket file by default(/run/containerd/containerd.sock). For other runtimes provide the appropriate path.

Use the following example to tune this:

## provide the container runtime and socket file path
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: pod-network-rate-limit-sa
  experiments:
  - name: pod-network-rate-limit
    spec:
      components:
        env:
        # runtime for the container
        # supports docker, containerd, crio
        - name: CONTAINER_RUNTIME
          value: 'containerd'
        # path of the socket file
        - name: SOCKET_PATH
          value: '/run/containerd/containerd.sock'
        - name: TOTAL_CHAOS_DURATION
          value: '60'