Network Chaos Scenario using Krkn

network_chaos:                                    # Scenario to create an outage by simulating random variations in the network.
  duration: 300                                   # In seconds - duration network chaos will be applied.
  node_name:                                      # Comma separated node names on which scenario has to be injected.
  label_selector: node-role.kubernetes.io/master  # When node_name is not specified, a node with matching label_selector is selected for running the scenario.
  instance_count: 1                               # Number of nodes in which to execute network chaos.
  interfaces:                                     # List of interface on which to apply the network restriction.
  - "ens5"                                        # Interface name would be the Kernel host network interface name.
  execution: serial|parallel                      # Execute each of the egress options as a single scenario(parallel) or as separate scenario(serial).
  egress:
    latency: 500ms
    loss: 50%                                    # percentage
    bandwidth: 10mbit

- id: network_chaos
  config:
    node_interface_name:                            # Dictionary with key as node name(s) and value as a list of its interfaces to test
      ip-10-0-128-153.us-west-2.compute.internal:
        - ens5
        - genev_sys_6081
    label_selector: node-role.kubernetes.io/master  # When node_interface_name is not specified, nodes with matching label_selector is selected for node chaos scenario injection
    instance_count: 1                               # Number of nodes to perform action/select that match the label selector
    kubeconfig_path: ~/.kube/config                 # Path to kubernetes config file. If not specified, it defaults to ~/.kube/config
    execution_type: parallel                        # Execute each of the ingress options as a single scenario(parallel) or as separate scenario(serial).
    network_params:
        latency: 500ms
        loss: '50%'
        bandwidth: 10mbit
    wait_duration: 120
    test_duration: 60
'''

Note: For ingress traffic shaping, ensure that your node doesn't have any [IFB](https://wiki.linuxfoundation.org/networking/ifb) interfaces already present. The scenario relies on creating IFBs to do the shaping, and they are deleted at the end of the scenario.


##### Steps
 - Pick the nodes to introduce the network anomaly either from node_name or label_selector.
 - Verify interface list in one of the nodes or use the interface with a default route, as test interface, if no interface is specified by the user.
 - Set traffic shaping config on node's interface using tc and netem.
 - Wait for the duration time.
 - Remove traffic shaping config on node's interface.
 - Remove the job that spawned the pod.