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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 docker, supported values: docker, containerd and crio for litmus and only docker for pumba LIB
SOCKET_PATH Path of the containerd/crio/docker socket file Defaults to `/var/run/docker.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 docker.
  • SOCKET_PATH: It contains path of docker socket file by default(/var/run/docker.sock). For containerd, specify path as /var/containerd/containerd.sock. For crio, speecify 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: "docker"
# path of the socket file
- name: SOCKET_PATH
value: "/var/run/docker.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"