쿠버1탄-30. 쿠버네티스 - 오토스케일링
다음은 쿠버네티스 스터디 자료를 참고해 정리한 내용입니다.
<1> 오토 스케일링 3가지
<2> 부하 테스트 환경 만들기
<3> 부하 테스트
<4> 다음 과정
<1> 오토 스케일링 3가지
1
HPA - 서버수를 늘리는 것 , Scale-Out
(Horizontal Pod Autoscaling)
2
VPA - 서버 사용을 높이는것, 스케일 업. Scale-UP
(Vertical Pod Autoscaling)
3
CA는 Node 수를 늘리는것
Cluster Autocaler
CA 는 클라우드 사업자가 제공해야 한다.
node 수 자체를 늘려준다.
4
HPA (pod 늘리기)
metrics-server 가 node에 있는 Kubelet 을 통해 pod와 node 정보를 수집한다.
리소스 API를 생성해 정보를 전달한다.
외부에서 kubectl top 으로 Resource API를 호출해 정보 확인이 가능하다.
HPA에 전달해 , ReplicaSet 에 이야기해서 늘린다.
그림 소개 : 출처 - 김태민님 기술 블로그
<2> 부하 테스트 환경 만들기
실습 자료
https://kubernetes.io/ko/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/
CPU 부하를 줘서 늘려보자~
1
모니터링
watch -d 'kubectl get ns,no,po,svc,deploy,rs,ing,ep -o wide'
or
watch -d 'kubectl top pod --use-protocol-buffers=true; echo; kubectl get deploy,pods,svc,ep -o wide'
2
cat << EOF > php-apache.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: php-apache
spec:
selector:
matchLabels:
run: php-apache
replicas: 1
template:
metadata:
labels:
run: php-apache
spec:
containers:
- name: php-apache
image: k8s.gcr.io/hpa-example
ports:
- containerPort: 80
resources:
limits:
cpu: 500m
requests:
cpu: 200m
---
apiVersion: v1
kind: Service
metadata:
name: php-apache
labels:
run: php-apache
spec:
ports:
- port: 80
selector:
run: php-apache
EOF
파일 다운 받으려면
3
kubectl apply -f php-apache.yaml
4
index.html에 접속 하면 CPU 과부하 연산 수행한다.
부하가 발생 된다.
5
kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 100.64.0.1 <none> 443/TCP 21h
php-apache ClusterIP 100.69.138.201 <none> 80/TCP 67s
6
현재 pod 1개
kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
php-apache-d4cf67d68-rh42c 1/1 Running 0 89s 100.112.62.138 ip-172-20-39-212.ap-southeast-1.compute.internal <none> <none>
7
Pod의 shell 실행해보자, 모니터링 하자
kubectl exec -it php-apache-d4cf67d68-rh42c -- bash
서버에 로그온한다.
root@php-apache-d4cf67d68-rh42c:/var/www/html# top
top - 09:50:38 up 21:23, 0 users, load average: 0.11, 0.14, 0.15
Tasks: 8 total, 1 running, 7 sleeping, 0 stopped, 0 zombie
%Cpu(s): 1.6 us, 2.3 sy, 0.0 ni, 94.9 id, 0.0 wa, 0.0 hi, 0.0 si, 1.2 st
KiB Mem: 3969424 total, 3841344 used, 128080 free, 85392 buffers
KiB Swap: 0 total, 0 used, 0 free. 3021380 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1 root 20 0 166260 19256 13984 S 0.0 0.5 0:00.10 apache2
8 www-data 20 0 166284 7132 1848 S 0.0 0.2 0:00.00 apache2
9 www-data 20 0 166284 7132 1848 S 0.0 0.2 0:00.00 apache2
10 www-data 20 0 166284 7132 1848 S 0.0 0.2 0:00.00 apache2
root@php-apache-d4cf67d68-rh42c:/var/www/html# exit
8
Pod가 생성된 node에서 모니터링
htop
<3> 부하 테스트
1
kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/kubernetes ClusterIP 100.64.0.1 <none> 443/TCP 17m <none>
service/php-apache ClusterIP 100.71.163.94 <none> 80/TCP 9m18s run=php-apache
2
SVCIP=<SVC IP>
SVCIP=100.71.163.94
curl $SVCIP;echo
OK!
3
1초에 한번 수행
while true;do curl -s $SVCIP; sleep 1; done
0.1초에 한번 수행
while true;do curl -s $SVCIP; sleep 0.1; done
while true;do curl -s $SVCIP; sleep 0.01; done
4
cat << EOF > php-apache.yaml
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
name: php-apache
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: php-apache
minReplicas: 1
maxReplicas: 10
targetCPUUtilizationPercentage: 50
EOF
리플리카스가 최소 1개, 최대 10개까지
total이 cpu가 50% 넘어가면 늘려줌
kubectl apply -f php-apache.yaml
6
모니터링
watch -d 'kubectl get hpa,deploy,pods,svc,ep -o wide'
while true; do kubectl top pod --use-protocol-buffers=true; sleep 1; done
7
파드가 생성된 노드들에서 모니터링 실행
htop
8
HPA 생성
kubectl apply -f php-apache.yaml
horizontalpodautoscaler.autoscaling/php-apache created
or
kubectl apply -f https://raw.githubusercontent.com/kubernetes/website/main/content/ko/examples/application/hpa/php-apache.yaml
9
모니터링 - 이 명령어는 모니터링이고 과부하 발생 아닙니다!
while true; do kubectl get hpa; sleep 1; done
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
php-apache Deployment/php-apache 0%/50% 1 10 1 52s
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
php-apache Deployment/php-apache 0%/50% 1 10 1 53s
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
php-apache Deployment/php-apache 0%/50% 1 10 1 54s
10
확인
kubectl describe hpa php-apache
Name: php-apache
Namespace: default
Labels: <none>
Annotations: <none>
CreationTimestamp: Mon, 19 Jul 2021 10:02:12 +0000
Reference: Deployment/php-apache
Metrics: ( current / target )
resource cpu on pods (as a percentage of request): 0% (1m) / 50%
Min replicas: 1
Max replicas: 10
Deployment pods: 1 current / 1 desired
Conditions:
Type Status Reason Message
---- ------ ------ -------
AbleToScale True ScaleDownStabilized recent recommendations were higher than current one, applying the highest recent recommendation
ScalingActive True ValidMetricFound the HPA was able to successfully calculate a replica count from cpu resource utilization (percentage of request)
ScalingLimited False DesiredWithinRange the desired count is within the acceptable range
Events: <none>
11
과부하 발생 테스트
kubectl get svc
ubuntu@ip-172-20-40-2:~$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 100.64.0.1 <none> 443/TCP 21h
php-apache ClusterIP 100.69.138.201 <none> 80/TCP 18m
SVCIP=<SVC IP>
SVCIP=100.69.138.201
curl $SVCIP;echo
while true;do curl -s $SVCIP; sleep 1; done
while true;do curl -s $SVCIP; sleep 0.1; done
while true;do curl -s $SVCIP; sleep 0.01; done
12
파드 갯수 증가 확인
1개 -> 2개 -> 5개
watch -d 'kubectl get hpa,deploy,pods,svc,ep -o wide'
kubectl get pod
NAME READY STATUS RESTARTS AGE
php-apache-d4cf67d68-28svt 1/1 Running 0 80s
php-apache-d4cf67d68-jcvlk 1/1 Running 0 16m
php-apache-d4cf67d68-lxxl2 1/1 Running 0 95s
php-apache-d4cf67d68-tv4f2 1/1 Running 0 95s
php-apache-d4cf67d68-vthrd 1/1 Running 0 110s
<4> 다음 과정
https://brunch.co.kr/@topasvga/1744
감사합니다.
