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Pod network duplication

Pod network duplication is a Kubernetes pod-level chaos fault that injects chaos to disrupt the network connectivity to Kubernetes pods.

  • It injects chaos on the specific container by starting a traffic control (tc) process with netem rules to add egress delays.
  • It determines the application's resilience to duplicate network.

Pod Network Duplication

Usage​

View fault usage
It determines the application's resilience to duplicate network. It simulates degraded network with varied percentages of dropped packets between microservices (dropped at the destination).

Prerequisites​

  • Kubernetes> 1.16.

Default validations​

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

Fault tunables​

Fault 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 latency Optional Applicable for containerd & CRI-O runtime only. Even with these runtimes, if the value is not provided, it injects chaos on the first container of the pod
NETWORK_PACKET_DUPLICATION_PERCENTAGE The packet duplication in percentage Optional Default to 100 percentage
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 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
PODS_AFFECTED_PERC The Percentage of total pods to target Defaults to 0 (corresponds to 1 replica), provide numeric value only
TC_IMAGE Image used for traffic control in linux default value is `gaiadocker/iproute2`
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.

Network packet duplication​

It defines the network packet duplication percentage to be injected in the targeted application. It can be tuned via NETWORK_PACKET_DUPLICATION_PERCENTAGE ENV.

Use the following example to tune this:

# it injects network-duplication for 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: litmus-admin
  experiments:
    - name: pod-network-duplication
      spec:
        components:
          env:
            # network packet duplication percentage
            - name: NETWORK_PACKET_DUPLICATION_PERCENTAGE
              value: "100"
            - name: TOTAL_CHAOS_DURATION
              value: "60"

Destination IPs and destination hosts​

The network faults 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 injects 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: litmus-admin
  experiments:
    - name: pod-network-duplication
      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"

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: litmus-admin
  experiments:
    - name: pod-network-duplication
      spec:
        components:
          env:
            # name of the network interface
            - name: NETWORK_INTERFACE
              value: "eth0"
            - name: TOTAL_CHAOS_DURATION
              value: "60"

Container runtime and 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(/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 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: litmus-admin
  experiments:
    - name: pod-network-duplication
      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"
            - name: TOTAL_CHAOS_DURATION
              VALUE: "60"