Lambda delete function concurrency

Lambda delete function concurrency is an AWS fault that deletes the Lambda function's reserved concurrency, thereby ensuring that the function has adequate unreserved concurrency to run.

Use cases

Lambda delete function concurrency examines the performance of the running Lambda application, if the Lambda function lacks sufficient concurrency.

Prerequisites

• Kubernetes >= 1.17
• Reserved concurrency must be set on the target Lambda function.
• Lambda function must be up and running.
• Kubernetes secret must have the AWS access configuration (key) 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 = XXXXXXXXXXXXXXX

tip

HCE recommends that you use the same secret name, that is, cloud-secret. Otherwise, you will need to update the AWS_SHARED_CREDENTIALS_FILE environment variable in the fault template with the new secret name and you won't be able to use the default health check probes.

Below is an example AWS policy to execute the fault.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "lambda:UpdateFunctionConfiguration",
                "lambda:GetFunctionConcurrency",
                "lambda:GetFunction",
                "lambda:DeleteFunctionConcurrency",
                "lambda:PutFunctionConcurrency"
            ],
            "Resource": "*"
        }
    ]
}

note

• Go to AWS named profile for chaos to use a different profile for AWS faults.
• Go to the superset permission/policy to execute all AWS faults.
• Go to common tunables and AWS-specific tunables to tune the common tunables for all faults and AWS-specific tunables.

Mandatory tunables

Tunable	Description	Notes
FUNCTION_NAME	Name of the target Lambda function. It supports a single function name.	For example, test-function.
FUNCTION_VERSION	Specifies the version of the function.	Default: $LATEST.
REGION	Region name of the target Lambda function.	For example, us-east-2.

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. For more information, go to duration of the chaos.
AWS_SHARED_CREDENTIALS_FILE	Path to the AWS secret credentials.	Default: /tmp/cloud_config.yml.
CHAOS_INTERVAL	Time interval between two successive deletions of reserved concurrency (in seconds).	Default: 30 s. For more information, go to chaos interval.
RAMP_TIME	Period to wait before and after injecting chaos (in seconds).	For example, 30 s. For more information, go to ramp time.