locust-k8s

a Locust on k8s example for scalable load tests.

Preparation

0. Install Docker.
1. Install kubectl.
2. Install Minikube to generate a local cluster.
3. Install the latest Skaffold for easy and repeatable Kubernetes development.

How to play

1. Create a k8s cluster

make cluster

2. Run locust master and workers

skaffold dev  # `ctrl + c` to terminate

3. Run FastAPI Server

make api
curl localhost/random-number  # check the server is running

4. Load Tests

Go to http://localhost:8089, and set the host address and the number of v-users.

k8s will auto-scale pods to make concurrent requests if needed.

$ kubectl get hpa --watch       

NAME                REFERENCE                  TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
locust-worker-hpa   Deployment/locust-worker   <unknown>/50%   1         10        1          21s
locust-worker-hpa   Deployment/locust-worker   73%/50%         1         10        1          45s
locust-worker-hpa   Deployment/locust-worker   73%/50%         1         10        2          60s
locust-worker-hpa   Deployment/locust-worker   91%/50%         1         10        2          75s
locust-worker-hpa   Deployment/locust-worker   81%/50%         1         10        2          90s
locust-worker-hpa   Deployment/locust-worker   78%/50%         1         10        2          105s
locust-worker-hpa   Deployment/locust-worker   85%/50%         1         10        4          2m
locust-worker-hpa   Deployment/locust-worker   63%/50%         1         10        4          2m15s
locust-worker-hpa   Deployment/locust-worker   38%/50%         1         10        4          2m30s

Delete the cluster

make finalize

Change the test scenario

Modify k8s/configmap.yaml. skaffold will instantly apply the changes.

apiVersion: v1
kind: ConfigMap
metadata:
  name: locust-configmap
data:
  locustfile.py: |
    from locust import FastHttpUser, between, task

    class QuickstartUser(FastHttpUser):

        wait_time = between(1, 3)

        @task
        def get_random_number(self):
            self.client.get("/random-number")

• Reference: http://docs.locust.io/en/stable/writing-a-locustfile.html

Change api server

Modify server/main.py.