Skip to main content

VMware network loss

VMware network loss injects network packet loss from the VMware VM(s) into the application (or service).

  • This results in flaky access to the application.
  • It checks the performance of the application (or process) running on the VMware VM(s).

VMware Network Loss

Use cases​

  • VMware network loss simulates issues within the VM network (or microservice) communication across services in different hosts.
  • It determines the impact of degradation while accessing a microservice.
  • The VM may stall or get corrupted while waiting endlessly for a packet. The fault limits the impact (blast radius) to the traffic that you wish to test by specifying the IP addresses.
  • It simulates degraded network with varied percentages of dropped packets between microservices.
  • It simulates loss of access to specific third party (or dependent) services (or components).
  • It simulates blackhole against traffic to a given availability zone, that is, failure simulation of availability zones.
  • It simulates network partitions (split-brain) between peer replicas for a stateful application.
note
  • Kubernetes > 1.16 is required to execute this fault.
  • Appropriate vCenter permissions should be provided to start and stop the VMs.
  • The VM should be in a healthy state before and after injecting chaos.
  • Kubernetes secret has to be created that has the Vcenter credentials in the CHAOS_NAMESPACE. VM credentials can be passed as secrets or as a ChaosEngine environment variable. Below is a sample secret file:
apiVersion: v1
kind: Secret
metadata:
  name: vcenter-secret
  namespace: litmus
type: Opaque
stringData:
    VCENTERSERVER: XXXXXXXXXXX
    VCENTERUSER: XXXXXXXXXXXXX
    VCENTERPASS: XXXXXXXXXXXXX

Fault tunables​

Mandatory fields

Variables Description Notes
VM_NAMES Names of the target VMs as comma-separated values. For example, vm-1,vm-2.
VM_USER_NAME Username of the target VM(s). Multiple usernames can be provided as comma-separated values which corresponds to more than one VM under chaos. It is used to run the govc command.
VM_PASSWORD Password for the target VM(s). It is used to run the govc command.

Optional fields

Variables Description Notes
TOTAL_CHAOS_DURATION Duration that you specify, through which chaos is injected into the target resource (in seconds). Defaults to 30s. For more information, go to duration of the chaos.
CHAOS_INTERVAL Time interval between two successive instance terminations (in seconds). Defaults to 30s. For more information, go to chaos interval.
NETWORK_PACKET_LOSS_PERCENTAGE Packets lost during transmission (in percent). Defaults to 100 %. For more information, go to network packet loss.
DESTINATION_IPS IP addresses of the services or pods whose accessibility you want to affect. You can also specify a CIDR block. Comma-separated IPs (or CIDRs) can be provided. If it has not been provided, network chaos is induced on all IPs (or destinations). For more information, go to run with destination IPs.
DESTINATION_HOSTS DNS names (or FQDN names) of the services whose accessibility is affected. If it has not been provided, network chaos is induced on all IPs (or destinations). For more information, go to run with destination hosts.
SEQUENCE Sequence of chaos execution for multiple instances. Defaults to parallel. Supports serial sequence as well. For more information, go to sequence of chaos execution.
RAMP_TIME Period to wait before and after injecting chaos (in seconds). For example, 30s. For more information, go to ramp time.

Secret fields

Variables Description Notes
GOVC_URL vCenter server URL used to perform API calls using the govc command. It is derived from a secret.
GOVC_USERNAME Username of the vCenter server used for authentication purposes. It can be set up using a secret.
GOVC_PASSWORD Password of the vCenter server used for authentication purposes. It can be set up using a secret.
GOVC_INSECURE Runs the govc command in insecure mode. It is set to true. It can be set up using a secret.

Network packet loss​

It specifies the network packet loss (in percentage) that is injected to the VM. Tune it by using the NETWORK_PACKET_LOSS_PERCENTAGE environment variable.

Use the following example to tune it:

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: VMware-engine
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: VMware-network-loss
    spec:
      components:
        env:
        # network packet loss percentage
        - name: NETWORK_PACKET_LOSS_PERCENTAGE
          value: '100'
        - name: VM_NAME
          value: 'vm-1,vm-2'
        - name: VM_USER_NAME
          value: 'ubuntu,debian'
        - name: VM_PASSWORD
          value: '123,123'

Run with destination IPs and destination hosts​

It specifies the IPs/hosts that interrupt traffic by default. You can tune this using the DESTINATION_IPS and DESTINATION_HOSTS environment variables, respectively.

DESTINATION_IPS: It contains the IP addresses of the services or the CIDR blocks (range of IPs) that impacts its accessibility. DESTINATION_HOSTS: It contains the DNS names of the services that impact its accessibility.

Use the following example to tune it:

## it injects the chaos for the egress traffic for specific ips/hosts
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: VMware-engine
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: VMware-network-loss
    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: 'google.com'
        - name: VM_NAME
          value: 'vm-1,vm-2'
        - name: VM_USER_NAME
          value: 'ubuntu,debian'
        - name: VM_PASSWORD
          value: '123,123'

Network interface​

It specifies the name of the ethernet interface that shapes the traffic. Tune it by using the NETWORK_INTERFACE environment variable. Its default value is eth0.

Use the following example to tune it:

## it injects the chaos for the egress traffic for specific ips/hosts
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: VMware-engine
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: VMware-network-loss
    spec:
      components:
        env:
        # name of the network interface
        - name: NETWORK_INTERFACE
          value: 'eth0'
        - name: VM_NAME
          value: 'vm-1,vm-2'
        - name: VM_USER_NAME
          value: 'ubuntu,debian'
        - name: VM_PASSWORD
          value: '123,123'