Application Load Balancer (ALB) Ingresses support automatic application scaling based on the QPS values collected by the ALB instances. This ensures the stability of the application and controls resource costs. This topic describes how to use ALB Ingresses to enable automatic application scaling based on QPS.
Step 1: Create an application and a Service
- Create a file named tea.yaml and copy the following content to the file:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment-basic
labels:
app: tea
spec:
replicas: 2
selector:
matchLabels:
app: tea
template:
metadata:
labels:
app: tea
spec:
containers:
- name: tea
image: nginx:1.7.9
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: tea-svc
namespace: default
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: tea
type: NodePort
- Run the following command to create an application and a Service:
kubectl apply -f tea.yaml
Step 2: Create an ALB Ingress
- Create an AlbConfig object.
- Create a file named alb-test-test.yaml and copy the following content to the file:
apiVersion: alibabacloud.com/v1
kind: AlbConfig
metadata:
name: alb-demo
spec:
config:
name: alb-test
addressType: Internet
zoneMappings:
- vSwitchId: vsw-uf6ccg2a9g71hx8go****
- vSwitchId: vsw-uf6nun9tql5t8nh15****
accessLogConfig:
logProject: "****"
logStore: "alb_****"
- zoneMappings: Specify at least two vSwitch IDs for the ALB Ingress. The vSwitches that you specify must be deployed in different zones of the VPC where your cluster resides.
- logProject: Specify the name of the Log Service project that you created.
- logStore: Specify the name of the Logstore that you want to use. The value of logStore must start with alb_. If the Logstore that you specify does not exist, the system automatically creates one with the name that you specified.
- Run the following command to create an AlbConfig object:
kubectl apply -f alb-test.yaml
- Create an IngressClass.
- Create a file named alb.yaml and copy the following content to the file:
apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
name: alb
spec:
controller: ingress.k8s.alibabacloud/alb
parameters:
apiGroup: alibabacloud.com
kind: AlbConfig
name: alb-demo
- Run the following command to create an IngressClass:
kubectl apply -f alb.yaml
- Create an ALB Ingress.
- Create a file named tea-ingress.yaml and copy the following content to the file:
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: tea-ingress
spec:
ingressClassName: alb
rules:
- host: demo.ingress.top
http:
paths:
- path: /tea
pathType: Prefix
backend:
service:
name: tea-svc
port:
number: 80
- Run the following command to create an ALB Ingress:
kubectl apply -f tea-ingress.yaml
- Run the following command to query the
ADDRESS parameter of the ALB Ingress:
Expected output:
NAME CLASS HOSTS ADDRESS PORTS AGE
tea-ingress alb demo.ingress.top alb-110zvs5nhsvfv*****.cn-chengdu.alb.aliyuncs.com 80 7m5s
Step 3: Create an HPA
- Create a file named hpa.yaml and copy the following content to the file:
apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
name: ingress-hpa
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: nginx-deployment-basic
minReplicas: 2
maxReplicas: 10
metrics:
- type: External
external:
metric:
name: sls_alb_ingress_qps
# The sls_alb_ingress_qps metric is used to configure auto scaling based on QPS values.
selector:
matchLabels:
sls.project: "****" # Replace the value of sls.project with the Log Service project that you want to use.
sls.logstore: "alb_****" # Replace the value with the Logstore that you want to use.
sls.ingress.route: "default-tea-svc-80"
# Specify the value of the sls.ingress.route parameter in the <namespace>-<svc>-<port> format. Example: default-nginx-80.
target:
type: AverageValue
# The type parameter is set to AverageValue, which indicates that the average QPS value of each pod is used to determine whether to perform scaling activities.
averageValue: 2
- Run the following command to create an HPA:
kubectl apply -f hpa.yaml
- Run the following command to query information about the HPA:
Expected output:
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
ingress-hpa Deployment/nginx-deployment-basic 0/2 (avg) 2 10 2 4h34m
- Run the following command to query information about the HPA:
kubectl describe hpa ingress-hpa
Expected output:
Name: ingress-hpa
Namespace: default
Labels: <none>
Annotations: <none>
CreationTimestamp: Tue, 31 Jan 2023 11:35:01 +0800
Reference: Deployment/nginx-deployment-basic
Metrics: ( current / target )
"sls_alb_ingress_qps" (target average value): 0 / 2
Min replicas: 2
Max replicas: 10
Deployment pods: 2 current / 2 desired
Step 4: Verify that the application can be automatically scaled based on the QPS value
- Verify that the application can be automatically scaled out based on the QPS value.
- Run the following commands to perform stress tests on the application:
ab -c 5 -n 5000 -H Host:demo.ingress.top http://alb-110zvs5nhsvfv*****.cn-chengdu.alb.aliyuncs.com/tea
- After the stress test is complete, run the following command to check whether the application is scaled out:
Expected output:
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
ingress-hpa Deployment/nginx-deployment-basic 12500m/2 (avg) 2 10 10 15m
The value of the REPLICAS parameter is 10. This indicates that the number of pods created for the application is increased to 10 as the QPS value increases.
- Verify that the application can be automatically scaled in based on the QPS value.
After the stress test is complete, the QPS value is decreased to 0, which is below the scale-in threshold. HPA automatically scales in the application.
After the stress test is complete, run the following command to check whether the application is scaled in:
Expected output:
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
ingress-hpa Deployment/nginx-deployment-basic 0/2 (avg) 2 10 2 60m
The value of the REPLICAS parameter is 2. This indicates that the number of pods created for the application is decreased as the QPS value decreases.
Elastic Compute Service (ECS)
Container Compute Service (ACS)
