Pod HTTP modify header

Pod HTTP modify header 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.
• It can cause modification of headers of requests and responses of the service. This can be used to test service resilience towards incorrect or incomplete headers.

Usage

View fault usage

This can be used to test service resilience towards incorrect or incomplete headers.

Prerequisites

• Kubernetes> 1.16.

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
HEADERS_MAP	Map of headers to modify/add	For example, {"X-Litmus-Test-Header": "X-Litmus-Test-Value"}. To remove a header, just set the value to ""; For example, {"X-Litmus-Test-Header": ""}
HEADER_MODE	Whether to modify response headers or request headers. Accepted values: request, response	Defaults to response

Optional fields

Variables	Description	Notes
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 header 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. It can be tuned via TARGET_SERVICE_PORT ENV.

Use the following example to tune this:

## 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-chaos
      spec:
        components:
          env:
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"
            # map of headers to modify/add
            - name: HEADERS_MAP
              value: '{"X-Litmus-Test-Header": "X-Litmus-Test-Value"}'

Proxy port

It defines the port on which the proxy server will listen for requests. It can be tuned via PROXY_PORT

Use the following example to tune this:

## 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-chaos
      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"
            # map of headers to modify/add
            - name: HEADERS_MAP
              value: '{"X-Litmus-Test-Header": "X-Litmus-Test-Value"}'

Headers map

It is the map of headers that are to be modified or added to the Http request/response. It can be tuned via HEADERS_MAP ENV.

Use the following example to tune this:

## provide the headers as a map
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-chaos
      spec:
        components:
          env:
            # map of headers to modify/add; Eg: {"X-Litmus-Test-Header": "X-Litmus-Test-Value"}
            # to remove a header, just set the value to ""; Eg: {"X-Litmus-Test-Header": ""}
            - name: HEADERS_MAP
              value: '{"X-Litmus-Test-Header": "X-Litmus-Test-Value"}'
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"

Header mode

It defined whether the request or the response header has to be modified. It can be tuned via HEADER_MODE ENV.

Use the following example to tune this:

## provide the mode of the header modification; request/response
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-chaos
      spec:
        components:
          env:
            # whether to modify response headers or request headers. Accepted values: request, response
            - name: HEADER_MODE
              value: "response"
            # provide the port of the targeted service
            - name: TARGET_SERVICE_PORT
              value: "80"
            # map of headers to modify/add
            - name: HEADERS_MAP
              value: '{"X-Litmus-Test-Header": "X-Litmus-Test-Value"}'

Toxicity

It defines the toxicity value to be added to the http request. It can be tuned via TOXICITY environment variable. Toxicity value defines the percentage of the total number of http requests to be affected.

Use the following example to tune this:

## 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-header
      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"

Network interface

It defines the network interface to be used for the proxy. It can be tuned via NETWORK_INTERFACE environment variable.

Use the following example to tune this:

## 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-chaos
      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"
            # map of headers to modify/add
            - name: HEADERS_MAP
              value: '{"X-Litmus-Test-Header": "X-Litmus-Test-Value"}'

Container runtime and socket path

It defines the CONTAINER_RUNTIME and SOCKET_PATH environment variables 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-chaos
      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"
            # map of headers to modify/add
            - name: HEADERS_MAP
              value: '{"X-Litmus-Test-Header": "X-Litmus-Test-Value"}'