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第 4 部分:负载测试与自动扩缩容

难度:中级 预计时间:45 分钟 最后更新:February 22, 2026

学习目标

  • 使用 k6 和 Locust 设计并执行负载测试场景
  • 实时观察 KEDA 驱动的 Pod 自动扩缩容
  • 在负载突增期间监控 Karpenter Node 自动扩缩容
  • 构建用于可视化扩缩容事件的 Grafana 仪表板

前提条件

  • [ ] 已完成第 3 部分:MSA 部署
  • [ ] 正在运行已配置 OTel 插桩的 MSA 服务
  • [ ] 已配置 KEDA 和 Karpenter
  • [ ] 已在本地安装 k6(brew install k6apt install k6

负载测试与扩缩容时间线


练习 1:k6 负载测试场景

步骤

步骤 1.1:创建 k6 负载测试脚本

bash
cat > ~/obs-lab/k6-load-test.js << 'EOF'
import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate, Trend } from 'k6/metrics';

// Custom metrics
const errorRate = new Rate('errors');
const orderLatency = new Trend('order_latency', true);

// Test configuration
export const options = {
  stages: [
    // Phase 1: Ramp-up
    { duration: '2m', target: 50 },   // Warm up
    { duration: '3m', target: 100 },  // Ramp to 100 VUs

    // Phase 2: Sustained load
    { duration: '10m', target: 100 }, // Hold at 100 VUs

    // Phase 3: Spike
    { duration: '2m', target: 300 },  // Spike to 300 VUs
    { duration: '3m', target: 500 },  // Peak at 500 VUs
    { duration: '2m', target: 500 },  // Hold peak

    // Phase 4: Cool-down
    { duration: '3m', target: 100 },  // Ramp down
    { duration: '2m', target: 50 },   // Further down
    { duration: '3m', target: 0 },    // Complete cool-down
  ],
  thresholds: {
    http_req_duration: ['p(95)<500', 'p(99)<1000'],
    errors: ['rate<0.1'],
    order_latency: ['p(95)<800'],
  },
};

const BASE_URL = __ENV.API_URL || 'http://api-gateway.msa.svc.cluster.local:8080';

// Test data
const products = ['PROD-001', 'PROD-002', 'PROD-003', 'PROD-004', 'PROD-005'];
const quantities = [1, 2, 3, 5, 10];

function randomItem(arr) {
  return arr[Math.floor(Math.random() * arr.length)];
}

function generateOrder() {
  return {
    customer_id: `CUST-${Math.floor(Math.random() * 10000)}`,
    product_id: randomItem(products),
    quantity: randomItem(quantities),
    payment_method: Math.random() > 0.5 ? 'credit_card' : 'debit_card',
  };
}

export default function () {
  // Scenario 1: Create Order (60% of traffic)
  if (Math.random() < 0.6) {
    const orderPayload = JSON.stringify(generateOrder());
    const orderStart = Date.now();

    const orderRes = http.post(`${BASE_URL}/api/v1/orders`, orderPayload, {
      headers: {
        'Content-Type': 'application/json',
        'X-Request-ID': `req-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
      },
      tags: { name: 'CreateOrder' },
    });

    orderLatency.add(Date.now() - orderStart);

    const orderSuccess = check(orderRes, {
      'order created': (r) => r.status === 201,
      'order has id': (r) => r.json('order_id') !== undefined,
    });
    errorRate.add(!orderSuccess);
  }

  // Scenario 2: Get Order Status (30% of traffic)
  else if (Math.random() < 0.9) {
    const orderId = `ORD-${Math.floor(Math.random() * 100000)}`;
    const statusRes = http.get(`${BASE_URL}/api/v1/orders/${orderId}`, {
      tags: { name: 'GetOrderStatus' },
    });

    const statusSuccess = check(statusRes, {
      'status retrieved': (r) => r.status === 200 || r.status === 404,
    });
    errorRate.add(!statusSuccess);
  }

  // Scenario 3: List Orders (10% of traffic)
  else {
    const listRes = http.get(`${BASE_URL}/api/v1/orders?limit=10`, {
      tags: { name: 'ListOrders' },
    });

    const listSuccess = check(listRes, {
      'list retrieved': (r) => r.status === 200,
    });
    errorRate.add(!listSuccess);
  }

  // Think time
  sleep(Math.random() * 2 + 0.5);
}

export function handleSummary(data) {
  return {
    'stdout': textSummary(data, { indent: ' ', enableColors: true }),
    '/tmp/k6-summary.json': JSON.stringify(data),
  };
}
EOF

步骤 1.2:负载测试阶段说明

阶段时长VU目的
预热5 分钟10 → 100逐步预热,触发初始扩缩容
持续负载10 分钟100稳态,观察稳定指标
突增7 分钟100 → 500压力测试,触发快速扩缩容
冷却8 分钟500 → 0观察缩容,清理资源

步骤 1.3:获取 API Gateway URL

bash
kubectl config use-context $(kubectl config get-contexts -o name | grep obs-service)

API_URL=$(kubectl -n msa get svc api-gateway \
  -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')

echo "API Gateway URL: http://$API_URL:8080"

步骤 1.4:运行 k6 负载测试

bash
# Run load test
k6 run --env API_URL=http://$API_URL:8080 ~/obs-lab/k6-load-test.js

# Or run with output to Prometheus
k6 run --env API_URL=http://$API_URL:8080 \
  --out experimental-prometheus-rw \
  ~/obs-lab/k6-load-test.js

练习 2:Locust 替代方案(基于 Python)

步骤

步骤 2.1:创建 Locust Deployment

bash
cat <<'EOF' | kubectl apply -f -
apiVersion: v1
kind: ConfigMap
metadata:
  name: locust-script
  namespace: msa
data:
  locustfile.py: |
    from locust import HttpUser, task, between
    import random
    import json

    class OrderUser(HttpUser):
        wait_time = between(0.5, 2)

        products = ['PROD-001', 'PROD-002', 'PROD-003', 'PROD-004', 'PROD-005']

        @task(6)
        def create_order(self):
            order = {
                'customer_id': f'CUST-{random.randint(1, 10000)}',
                'product_id': random.choice(self.products),
                'quantity': random.choice([1, 2, 3, 5, 10]),
                'payment_method': random.choice(['credit_card', 'debit_card']),
            }
            with self.client.post(
                '/api/v1/orders',
                json=order,
                headers={'Content-Type': 'application/json'},
                catch_response=True
            ) as response:
                if response.status_code == 201:
                    response.success()
                else:
                    response.failure(f'Status: {response.status_code}')

        @task(3)
        def get_order_status(self):
            order_id = f'ORD-{random.randint(1, 100000)}'
            self.client.get(f'/api/v1/orders/{order_id}')

        @task(1)
        def list_orders(self):
            self.client.get('/api/v1/orders?limit=10')
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: locust-master
  namespace: msa
spec:
  replicas: 1
  selector:
    matchLabels:
      app: locust
      role: master
  template:
    metadata:
      labels:
        app: locust
        role: master
    spec:
      containers:
        - name: locust
          image: locustio/locust:2.22.0
          ports:
            - containerPort: 8089
            - containerPort: 5557
          command:
            - locust
            - --master
            - --host=http://api-gateway:8080
          volumeMounts:
            - name: locust-script
              mountPath: /home/locust
          resources:
            requests:
              cpu: 100m
              memory: 256Mi
      volumes:
        - name: locust-script
          configMap:
            name: locust-script
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: locust-worker
  namespace: msa
spec:
  replicas: 4
  selector:
    matchLabels:
      app: locust
      role: worker
  template:
    metadata:
      labels:
        app: locust
        role: worker
    spec:
      containers:
        - name: locust
          image: locustio/locust:2.22.0
          command:
            - locust
            - --worker
            - --master-host=locust-master
          volumeMounts:
            - name: locust-script
              mountPath: /home/locust
          resources:
            requests:
              cpu: 500m
              memory: 512Mi
      volumes:
        - name: locust-script
          configMap:
            name: locust-script
---
apiVersion: v1
kind: Service
metadata:
  name: locust-master
  namespace: msa
spec:
  selector:
    app: locust
    role: master
  ports:
    - name: web
      port: 8089
      targetPort: 8089
    - name: master
      port: 5557
      targetPort: 5557
  type: LoadBalancer
EOF

步骤 2.2:访问 Locust Web UI

bash
LOCUST_URL=$(kubectl -n msa get svc locust-master \
  -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')

echo "Locust UI: http://$LOCUST_URL:8089"

练习 3:在负载期间观察自动扩缩容

步骤

步骤 3.1:打开多个用于监控的终端窗口

bash
# Terminal 1: Watch Pod scaling
watch -n 2 'kubectl get pods -n msa -l app=order-service -o wide'

# Terminal 2: Watch HPA status
watch -n 5 'kubectl get hpa -n msa'

# Terminal 3: Watch Node scaling (Karpenter)
watch -n 10 'kubectl get nodes -l workload-type=msa'

# Terminal 4: Watch Karpenter logs
kubectl logs -n karpenter -l app.kubernetes.io/name=karpenter -f

步骤 3.2:负载测试期间的观察要点

指标观察位置预期行为
Pod 数量kubectl get pods -n msa2 → 8 → 30 → 2
HPA 指标kubectl get hpa -n msaCPU/请求速率增加
Node 数量kubectl get nodes配置新的 Node
SQS 队列深度AWS Console / CloudWatch峰值期间突增
Prometheus 指标Grafana Explore请求速率、延迟
TraceTempo / Grafana端到端延迟

步骤 3.3:KEDA 扩缩容事件

bash
# Watch KEDA events
kubectl get events -n msa --field-selector reason=KEDAScaleTargetActivated -w

# Check ScaledObject status
kubectl describe scaledobject -n msa order-service-scaler

步骤 3.4:Karpenter 配置事件

bash
# Watch node provisioning
kubectl get events -A --field-selector reason=Provisioned -w

# Check NodePool status
kubectl describe nodepool msa-workloads

练习 4:冷却与缩容观察

步骤

步骤 4.1:在负载测试完成后监控缩容

bash
# Watch Pod termination
kubectl get pods -n msa -l app=order-service -w

# Watch node consolidation
kubectl get events -A --field-selector reason=Consolidated -w

步骤 4.2:缩容时间线

负载结束后的时间Pod 数量Node 数量说明
0 分钟308+峰值状态
2 分钟208+HPA 冷却开始
5 分钟106Pod 正在终止
10 分钟44Karpenter 正在整合
15 分钟23接近基准状态
20 分钟22已恢复基准状态

步骤 4.3:验证成本优化

bash
# Check spot instance usage
kubectl get nodes -o custom-columns=NAME:.metadata.name,TYPE:.metadata.labels.karpenter\\.sh/capacity-type,INSTANCE:.metadata.labels.node\\.kubernetes\\.io/instance-type

# Expected: Mix of spot and on-demand instances

练习 5:Grafana 扩缩容仪表板

步骤

步骤 5.1:创建扩缩容仪表板面板

面板指标查询可视化
Pod 数量sum(kube_deployment_status_replicas{namespace="msa"}) by (deployment)时间序列
Node 数量count(kube_node_info{node=~".*msa.*"})统计
CPU 使用率sum(rate(container_cpu_usage_seconds_total{namespace="msa"}[5m])) by (pod)时间序列
内存使用率sum(container_memory_working_set_bytes{namespace="msa"}) by (pod)时间序列
SQS 队列深度aws_sqs_approximate_number_of_messages_visible_average{queue_name="obs-lab-orders"}时间序列
请求速率sum(rate(http_server_request_count{namespace="msa"}[1m])) by (service)时间序列
错误率sum(rate(http_server_request_count{namespace="msa",http_status_code=~"5.."}[1m])) / sum(rate(http_server_request_count{namespace="msa"}[1m]))仪表盘
P99 延迟histogram_quantile(0.99, sum(rate(http_server_request_duration_seconds_bucket{namespace="msa"}[5m])) by (le, service))时间序列

步骤 5.2:导入仪表板 JSON

bash
cat > /tmp/scaling-dashboard.json << 'EOF'
{
  "dashboard": {
    "title": "MSA Scaling Dashboard",
    "tags": ["obs-lab", "scaling", "k6"],
    "timezone": "browser",
    "panels": [
      {
        "title": "Pod Replicas by Deployment",
        "type": "timeseries",
        "gridPos": {"h": 8, "w": 12, "x": 0, "y": 0},
        "targets": [{
          "expr": "sum(kube_deployment_status_replicas{namespace=\"msa\"}) by (deployment)",
          "legendFormat": "{{deployment}}"
        }]
      },
      {
        "title": "Node Count",
        "type": "stat",
        "gridPos": {"h": 4, "w": 6, "x": 12, "y": 0},
        "targets": [{
          "expr": "count(kube_node_info)"
        }]
      },
      {
        "title": "Request Rate",
        "type": "timeseries",
        "gridPos": {"h": 8, "w": 12, "x": 0, "y": 8},
        "targets": [{
          "expr": "sum(rate(http_server_request_count{namespace=\"msa\"}[1m])) by (service)",
          "legendFormat": "{{service}}"
        }]
      },
      {
        "title": "P99 Latency (ms)",
        "type": "timeseries",
        "gridPos": {"h": 8, "w": 12, "x": 12, "y": 8},
        "targets": [{
          "expr": "histogram_quantile(0.99, sum(rate(http_server_request_duration_seconds_bucket{namespace=\"msa\"}[5m])) by (le, service)) * 1000",
          "legendFormat": "{{service}}"
        }]
      }
    ]
  }
}
EOF

# Import via Grafana API
curl -X POST -H "Content-Type: application/json" \
  -u admin:ObsLab2026! \
  -d @/tmp/scaling-dashboard.json \
  "http://$GRAFANA_URL/api/dashboards/db"

步骤 5.3:为扩缩容事件创建注释

bash
# Add Prometheus recording rules for scaling events
cat <<'EOF' | kubectl apply -f -
apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  name: scaling-events
  namespace: monitoring
spec:
  groups:
    - name: scaling-events
      rules:
        - record: scaling:pod_scale_up
          expr: |
            changes(kube_deployment_status_replicas{namespace="msa"}[5m]) > 0
            and
            delta(kube_deployment_status_replicas{namespace="msa"}[5m]) > 0

        - record: scaling:pod_scale_down
          expr: |
            changes(kube_deployment_status_replicas{namespace="msa"}[5m]) > 0
            and
            delta(kube_deployment_status_replicas{namespace="msa"}[5m]) < 0

        - record: scaling:node_added
          expr: |
            changes(kube_node_created{node=~".*msa.*"}[10m]) > 0
EOF

验证

bash
# Open Grafana dashboard
echo "Grafana URL: http://$GRAFANA_URL"
echo "Dashboard: MSA Scaling Dashboard"

# Verify metrics are populated
curl -s -u admin:ObsLab2026! \
  "http://$GRAFANA_URL/api/datasources/proxy/1/api/v1/query?query=kube_deployment_status_replicas" | jq

总结

在本实验中,你已完成:

任务状态
k6 负载测试脚本已创建
Locust Deployment已部署
Pod 自动扩缩容(KEDA)已观察
Node 自动扩缩容(Karpenter)已观察
缩容行为已验证
扩缩容仪表板已创建

关键观察结果

指标基准峰值恢复后
Order Service Pod2302
Node 总数38+3
请求速率0500+ RPS0
P99 延迟<100ms<500ms<100ms
错误率0%<1%0%

清理

清理工作将在第 6 部分中执行。

故障排除

k6 无法访问 API Gateway
  • 验证 LoadBalancer 是否具有外部 IP:kubectl get svc -n msa api-gateway
  • 检查安全组是否允许入站流量
  • 测试连通性:curl http://$API_URL:8080/health
Pod 未扩缩容
  • 检查 HPA 状态:kubectl describe hpa -n msa
  • 验证 KEDA ScaledObject:kubectl describe scaledobject -n msa
  • 检查指标是否可用:kubectl top pods -n msa
Node 未配置
  • 检查 Karpenter 日志:kubectl logs -n karpenter -l app.kubernetes.io/name=karpenter
  • 验证 NodePool 限制:kubectl describe nodepool msa-workloads
  • 检查 AWS 账户中的 EC2 实例限制

后续步骤

继续学习第 5 部分:告警与 AIOps,以配置告警和 AI 驱动的事件响应。

参考资料