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Windows EC2 CPU hog

Introduction​

EC2 windows CPU hog induces CPU stress on the AWS Windows EC2 instances using Amazon SSM Run command. The SSM Run command is executed using SSM documentation that is built into the fault.

Windows EC2 CPU hog

Use cases​

EC2 windows CPU hog:

  • Simulates the situation of a lack of CPU for processes running on the instance, which degrades their performance.
  • Simulates slow application traffic or exhaustion of the resources, leading to degradation in the performance of processes on the instance.
note
  • Kubernetes version 1.17 or later is required to execute this fault.
  • The EC2 instance must be in a healthy state.
  • SSM agent must be installed and running on the target EC2 instance.
  • SSM IAM role must be attached to the target EC2 instance(s).
  • Kubernetes secret must have the AWS Access Key ID and Secret Access Key credentials in the CHAOS_NAMESPACE. Below is a sample secret file:
    apiVersion: v1
    kind: Secret
    metadata:
      name: cloud-secret
    type: Opaque
    stringData:
      cloud_config.yml: |-
        # Add the cloud AWS credentials respectively
        [default]
        aws_access_key_id = XXXXXXXXXXXXXXXXXXX
        aws_secret_access_key = XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  • Harness recommends using the same secret name, that is, cloud-secret. Otherwise, you must update the AWS_SHARED_CREDENTIALS_FILE environment variable in the fault template and you won't be able to use the default health check probes.
  • Go to AWS named profile for chaos to use a different profile for AWS faults.
  • Go to superset permission/policy to execute all AWS faults.

Here is an example AWS policy to execute the fault.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "ssm:GetDocument",
                "ssm:DescribeDocument",
                "ssm:GetParameter",
                "ssm:GetParameters",
                "ssm:SendCommand",
                "ssm:CancelCommand",
                "ssm:CreateDocument",
                "ssm:DeleteDocument",
                "ssm:GetCommandInvocation",          
                "ssm:UpdateInstanceInformation",
                "ssm:DescribeInstanceInformation"
            ],
            "Resource": "*"
        },
        {
            "Effect": "Allow",
            "Action": [
                "ec2messages:AcknowledgeMessage",
                "ec2messages:DeleteMessage",
                "ec2messages:FailMessage",
                "ec2messages:GetEndpoint",
                "ec2messages:GetMessages",
                "ec2messages:SendReply"
            ],
            "Resource": "*"
        },
        {
            "Effect": "Allow",
            "Action": [
                "ec2:DescribeInstanceStatus",
                "ec2:DescribeInstances"
            ],
            "Resource": [
                "*"
            ]
        }
    ]
}

Fault tunables​

Mandatory tunables

Tunable Description Notes
EC2_INSTANCE_ID ID(s) of the target EC2 instances. For example: i-044d3cb4b03b8af1f.
REGION AWS region ID where the EC2 instance has been created. For example: us-east-1.

Optional tunables

Tunable Description Notes
TOTAL_CHAOS_DURATION Duration that you specify, through which chaos is injected into the target resource (in seconds). Default: 30 s
AWS_SHARED_CREDENTIALS_FILE Path to the AWS secret credentials. Default: /tmp/cloud_config.yml.
CPU_CORE Number of CPU cores to consume. Default: 0. This means all available CPU cores are consumed.
SEQUENCE Sequence of chaos execution for multiple instances. Default: parallel. Supports serial and parallel.
RAMP_TIME Period to wait before and after injecting chaos (in seconds). For example, 30 s.

CPU core​

Number of CPU cores utilized on the EC2 instance. Tune it by using the CPU_CORE environment variable. All available CPU cores can be consumed by setting this variable to 0.

The following YAML snippet illustrates the use of this environment variable:

# CPU cores to utilize
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: windows-ec2-cpu-hog
    spec:
      components:
        env:
        - name: CPU_CORE
          VALUE: '2'
        # ID of the EC2 instance
        - name: EC2_INSTANCE_ID
          value: 'instance-1'
        # region for the EC2 instance
        - name: REGION
          value: 'us-east-1'

Multiple EC2 instances​

Multiple EC2 instances specified as comma-separated IDs targeted in one chaos run. Tune it by using the EC2_INSTANCE_ID environment variable.

The following YAML snippet illustrates the use of this environment variable:

# mutilple instance targets
apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: engine-nginx
spec:
  engineState: "active"
  chaosServiceAccount: litmus-admin
  experiments:
  - name: windows-ec2-cpu-hog
    spec:
      components:
        env:
        # ids of the EC2 instances
        - name: EC2_INSTANCE_ID
          value: 'instance-1,instance-2,instance-3'
        # region for the EC2 instance
        - name: REGION
          value: 'us-east-1'