Node Network Chaos

Injects network degradation (latency, packet loss, bandwidth) into a target node’s network interfaces using Linux tc rules.

Injects network degradation (latency, packet loss, bandwidth restriction) into a target node’s network interfaces using Linux tc (traffic control) rules. Unlike node-network-filter which blocks specific ports via iptables, this module shapes traffic at the interface level. Includes safety checks for existing tc rules on the node.

How to Run Node Network Chaos Scenarios

Choose your preferred method to run node network chaos scenarios:

Configuration

- id: node_network_chaos
  image: "quay.io/krkn-chaos/krkn-network-chaos:latest"
  wait_duration: 1
  test_duration: 60
  label_selector: ""
  service_account: ""
  instance_count: 1
  execution: parallel
  namespace: default
  # scenario specific settings
  target: "<node_name>"
  interfaces: []
  ingress: true
  egress: true
  latency: ""         # empty string to skip; or e.g. 100ms (units: us, ms, s)
  loss: 10           # percentage (no % symbol)
  bandwidth: 1gbit   # supported units: bit, kbit, mbit, gbit, tbit
  force: false
  taints: []

For the common module settings please refer to the documentation.

latency: network latency to inject. Format: integer followed by us (microseconds), ms (milliseconds), or s (seconds). Example: 100ms. Set to empty string to skip.
loss: packet loss percentage as a plain integer (no % symbol). Example: 10 means 10% packet loss. Set to empty string to skip.
bandwidth: bandwidth limit. Format: integer followed by bit, kbit, mbit, gbit, or tbit. Example: 100mbit. Set to empty string to skip.
interfaces: list of network interface names to target. Leave empty to auto-detect the node’s default interface.
ingress: apply rules to incoming traffic (default: true)
egress: apply rules to outgoing traffic (default: true)
target: the node name to target (used when label_selector is not set)
force: by default (false), if the target node already has tc rules configured, the scenario aborts with a warning to avoid damaging cluster networking. Set to true to override existing rules. A 10-second warning delay is inserted before proceeding. Use with caution.

Usage

To enable node network chaos scenarios edit the kraken config file, go to the section kraken -> chaos_scenarios of the yaml structure and add a new element to the list named network_chaos_ng_scenarios then add the desired scenario pointing to the scenario yaml file.

kraken:
    ...
    chaos_scenarios:
        - network_chaos_ng_scenarios:
            - scenarios/kube/node-network-chaos.yml

Note

You can specify multiple scenario files of the same type by adding additional paths to the list:

kraken:
    chaos_scenarios:
        - network_chaos_ng_scenarios:
            - scenarios/kube/node-network-chaos-1.yml
            - scenarios/kube/node-network-chaos-2.yml

You can also combine multiple different scenario types in the same config.yaml file. Scenario types can be specified in any order, and you can include the same scenario type multiple times:

kraken:
    chaos_scenarios:
        - network_chaos_ng_scenarios:
            - scenarios/kube/node-network-chaos.yml
        - pod_disruption_scenarios:
            - scenarios/pod-kill.yaml
        - node_scenarios:
            - scenarios/node-reboot.yaml

Warning

When force is set to false (default), the scenario will check if the target node already has complex tc queueing disciplines configured. If existing rules are detected, the scenario aborts to prevent damaging cluster networking. Only set force: true if you understand the implications of overriding existing traffic control rules.

Run

python run_kraken.py --config config/config.yaml

Not yet supported

node_network_chaos is not currently available as a krkn-hub container image. Use the Krkn tab to run this scenario directly.

Not yet supported

node_network_chaos is not currently available via krknctl. Use the Krkn tab to run this scenario directly.

Example scenario file: node-network-chaos.yml