locust

Trial Job - Locust

The Locust job uses Locust, based on the public locustio/locust image, to launch a load test and collect the metrics at the end of the job. The metrics are then pushed to the Prometheus Pushgateway.

Configuration

Environment Variable	Description	Default Value
LOCUSTFILE	Location of the locustfile to run	/mnt/locust/locustfile.py
HOST	Host to load test in the following format: "http://10.21.32.33"	http://localhost:8000
NUM_USERS	Number of concurrent locust users	200
SPAWN_RATE	The rate per second in which users are spawned	20
RUN_TIME	Duration of the load test in seconds	180
PUSHGATEWAY_URL	The URL used to push Locust test run metrics.

Metrics

The metrics below are exported from the result of the Locust test via the parse_metrics.py script, if a PUSHGATEWAY_URL environment variable is configured. Users can either setup their own Prometheus Pushgateway or use the prometheus setupTask in their experiment to provision a Pushgateway automatically.

Name
request_count
failure_count
average_response_time
min_response_time
max_response_time
average_content_size
requests_per_s
failures_per_s
p50
p66
p75
p80
p90
p95
p98
p99
p99_9
p99_99
p100

Example Kubernetes Manifest

The following Kubernetes Job manifest illustrates how you might leverage this trial job container. The environment variables are the arguments to the Locust CLI and the Prometheus Pushgateway URL. The locustfile is passed via a ConfigMap.

apiVersion: v1
kind: ConfigMap
metadata:
  name: locustconfig
data:
  locustfile.py: |
    from locust import HttpUser, task, between
    class MyUser(HttpUser):
        wait_time = between(1, 5)
        @task(1)
        def index(self):
            self.client.get("/api-url/endpoint/")
---
apiVersion: batch/v1
kind: Job
metadata:
  name: locust-1
spec:
  backoffLimit: 0
  template:
    spec:
      restartPolicy: Never
      containers:
      - name: minimal-load
        image: thestormforge/optimize-trials:latest-locust
        env:
        - name: HOST
          value: "http://api-endpoint:port-number"
        - name: NUM_USERS
          value: "200"
        - name: SPAWN_RATE
          value: "20"
        - name: RUN_TIME
          value: "180"
        - name: PUSHGATEWAY_URL
          value: "http://prometheus:9091/metrics/job/trialRun/instance/locust-1"
        volumeMounts:
          - name: locustconfig
            mountPath: /mnt/locust
      volumes:
      - name: locustconfig
        configMap:
          name: locustconfig
      - name: podinfo
        downwardAPI:
          items:
          - path: labels
            fieldRef:
              fieldPath: metadata.labels

NOTE: If you are using this in an experiment, keep in mind that some values are set automatically. In particular, the backoffLimit, restartPolicy, and PUSHGATEWAY_URL environment variable are all introduced when evaluating a trial's job template.