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Pod HTTP modify body

Pod HTTP modify body is a Kubernetes pod-level chaos fault that injects chaos on the service whose port is provided using the TARGET_SERVICE_PORT environment variable.

This is done by starting the proxy server and redirecting the traffic through the proxy server.
Can be used to overwrite the HTTP response body by providing the new body value as RESPONSE_BODY.
It can test the application's resilience to error or incorrect HTTP response body.

Pod HTTP Modify Body

Usage

View fault usage

It can test the application's resilience to erroneous or incorrect HTTP response body.

Prerequisites

Kubernetes> 1.17.

Default validations

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

Fault tunables

Fault tunables

Mandatory Fields

Variables	Description	Notes
TARGET_SERVICE_PORT	Port of the service to target	Defaults to port 80
RESPONSE_BODY	Body string to overwrite the http response body	If no value is provided, response will be an empty body. Defaults to empty body

Optional fields

Variables	Description	Notes
CONTENT_ENCODING	Encoding type to compress/encodde the response body	Accepted values are: gzip, deflate, br, identity. Defaults to none (no encoding)
CONTENT_TYPE	Content type of the response body	Defaults to text/plain
PROXY_PORT	Port where the proxy will be listening for requests	Defaults to 20000
NETWORK_INTERFACE	Network interface to be used for the proxy	Defaults to `eth0`
TOXICITY	Percentage of HTTP requests to be affected	Defaults to 100
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 duration of chaos injection (seconds)	Default (60s)
TARGET_PODS	Comma separated list of application pod name subjected to pod http modify body chaos	If not provided, it will select target pods randomly based on provided appLabels
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	For example, 30
SEQUENCE	It defines sequence of chaos execution for multiple target pods	Default value: parallel. Supported: serial, parallel

Fault examples

Common and pod-specific tunables

Refer to the common attributes and pod-specific tunables to tune the common tunables for all fault and pod specific tunables.

Target service port

It defines the port of the targeted service that is being targeted. You can tune it using the TARGET_SERVICE_PORT ENV.

Use the following example to tune it:

## provide the port of the targeted service
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: litmus-admin
  experiments:
    - name: pod-http-modify-body
      spec:
        components:
          env:
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"
            # provide the body string to overwrite the response body
            - name: RESPONSE_BODY
              value: "2000"

Proxy port

It defines the port on which the proxy server will listen for requests. You can tune it using the PROXY_PORT ENV.

Use the following example to tune it:

## provide the port for proxy server
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: litmus-admin
  experiments:
    - name: pod-http-modify-body
      spec:
        components:
          env:
            # provide the port for proxy server
            - name: PROXY_PORT
              value: "8080"
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"

Response body

It defines the body string that will overwrite the http response body. You can tune it using the RESPONSE_BODY ENV.

Use the following example to tune it:

## provide the response body value
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: litmus-admin
  experiments:
    - name: pod-http-modify-body
      spec:
        components:
          env:
            # provide the body string to overwrite the response body
            - name: RESPONSE_BODY
              value: "2000"
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"

Toxicity

It defines the toxicity value to be added to the http request. You can tune it using the TOXICITY ENV. Toxicity value defines the percentage of the total number of http requests to be affected.

Use the following example to tune it:

## provide the toxicity
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: litmus-admin
  experiments:
    - name: pod-http-modify-body
      spec:
        components:
          env:
            # toxicity is the probability of the request to be affected
            # provide the percentage value in the range of 0-100
            # 0 means no request will be affected and 100 means all request will be affected
            - name: TOXICITY
              value: "100"
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"

Content encoding and content type

It defines the content encoding and content type of the response body. You can tune it using the CONTENT_ENCODING and CONTENT_TYPE ENV.

Use the following example to tune it:

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: litmus-admin
  experiments:
    - name: pod-http-modify-body
      spec:
        components:
          env:
            # provide the encoding type for the response body
            # currently supported value are gzip, deflate
            # if empty no encoding will be applied
            - name: CONTENT_ENCODING
              value: "gzip"
            # provide the content type for the response body
            - name: CONTENT_TYPE
              value: "text/html"
            # provide the body string to overwrite the response body
            - name: RESPONSE_BODY
              value: "2000"
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"

Network interface

It defines the network interface to be used for the proxy. You can tune it using the NETWORK_INTERFACE environment variable.

Use the following example to tune it:

## provide the network interface for proxy
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  annotationCheck: "false"
  appinfo:
    appns: "default"
    applabel: "app=nginx"
    appkind: "deployment"
  chaosServiceAccount: litmus-admin
  experiments:
    - name: pod-http-modify-body
      spec:
        components:
          env:
            # provide the network interface for proxy
            - name: NETWORK_INTERFACE
              value: "eth0"
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"
            # provide the body string to overwrite the response body
            - name: RESPONSE_BODY
              value: "2000"

Container runtime and socket path

It defines the CONTAINER_RUNTIME and SOCKET_PATH environment variable to set the container runtime and socket file path, respectively.

CONTAINER_RUNTIME: It supports docker, containerd, and crio runtimes. The default value is containerd.
SOCKET_PATH: It contains path of containerd socket file by default(/run/containerd/containerd.sock). For docker, specify path as /var/run/docker.sock. For crio, specify path as /var/run/crio/crio.sock.

Use the following example to tune it:

## 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: litmus-admin
  experiments:
    - name: pod-http-modify-body
      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"
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"
            # provide the body string to overwrite the response body
            - name: RESPONSE_BODY
              value: "2000"

Usage
Prerequisites
Default validations
Fault tunables
Fault examples