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Pod HTTP latency

Pod HTTP latency is a Kubernetes pod-level chaos fault that injects HTTP response latency by starting proxy server and redirecting the traffic through it.

  • It injects the latency into the service whose port is specified using the TARGET_SERVICE_PORT environment variable.
  • It evaluates the application's resilience to lossy (or flaky) HTTP responses.

Pod HTTP Latency

Usage

View fault usage
This fault evaluates the application's resilience to lossy (or flaky) HTTP responses. It simulates latency to specific API services for (or from) a given microservice. It also simulates a slow response on specific third party (or dependent) components (or services).

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 targetDefaults to port 80
LATENCY Latency value in ms to be added to requests Defaults to 2000

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 latency 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-latency
spec:
components:
env:
# provide the port of the targeted service
- name: TARGET_SERVICE_PORT
value: "80"

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-latency
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"

Latency

It defines the latency value to be added to the http request. You can tune it using the LATENCY ENV.

Use the following example to tune it:

## provide the latency 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-latency
spec:
components:
env:
# provide the latency value
- name: LATENCY
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-latency
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. You can tune it using the NETWORK_INTERFACE ENV.

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-latency
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"

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-latency
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"