반응형
StatefulSet 이란?
- Pod의 상태를 유지해주는 컨트롤러
. Pod 이름
. Pod의 볼륨(스토리지)
rc-nginx.yaml
apiVersion: v1
kind: ReplicationController
metadata:
name: rc-nginx
spec:
replicas: 3
selector:
app: webui
template:
metadata:
name: nginx-pod
labels:
app: webui
spec:
containers:
- name: nginx-container
image: nginx:1.14
pod의 이름은 random hash 값으로 지정(fv24x, st9h1, xmvns)
# kubectl create -f rc-nginx.yaml
replicationcontroller/rc-nginx created
# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
rc-nginx-fv24x 1/1 Running 0 2m44s 10.44.0.2 node2.example.com <none> <none>
rc-nginx-st9hl 1/1 Running 0 2m44s 10.44.0.1 node2.example.com <none> <none>
rc-nginx-xmvns 1/1 Running 0 2m44s 10.36.0.1 node1.example.com <none> <none>
ReplicationController는 delete명령으로 pod 삭제시 pod의 개수를 보장하고 이름을 보장하지는 않음
# kubectl delete pod rc-nginx-fv24x
pod "rc-nginx-fv24x" deleted
# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
rc-nginx-pgjhj 1/1 Running 0 12s 10.36.0.2 node1.example.com <none> <none>
rc-nginx-st9hl 1/1 Running 0 3m30s 10.44.0.1 node2.example.com <none> <none>
rc-nginx-xmvns 1/1 Running 0 3m30s 10.36.0.1 node1.example.com <none> <none>
statefulset-exam.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: sf-nginx
spec:
replicas: 3
serviceName: sf-service
# podManagementPolicy: OrderedReady
podManagementPolicy: Parallel
selector:
matchLabels:
app: webui
template:
metadata:
name: nginx-pod
labels:
app: webui
spec:
containers:
- name: nginx-container
image: nginx:1.14statefulset은 serviceName을 꼭 명시해야함
podManagementPolicy: OrderedReady (pod를 순차적으로 실행)
podManagementPolicy: Parallel (pod를 병렬로 실행)
statefulset 의 경우 NAME을 보면 0,1,2 이름을 보장함
# kubectl create -f statefulset-exam.yaml
statefulset.apps/sf-nginx created
# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
rc-nginx-pgjhj 1/1 Running 0 13m 10.36.0.2 node1.example.com <none> <none>
rc-nginx-st9hl 1/1 Running 0 16m 10.44.0.1 node2.example.com <none> <none>
rc-nginx-xmvns 1/1 Running 0 16m 10.36.0.1 node1.example.com <none> <none>
sf-nginx-0 1/1 Running 0 17s 10.44.0.2 node2.example.com <none> <none>
sf-nginx-1 1/1 Running 0 17s 10.44.0.3 node2.example.com <none> <none>
sf-nginx-2 1/1 Running 0 17s 10.36.0.3 node1.example.com <none> <none>
sf-nginx-1 을 삭제할 경우 sf-nginx-1 이름으로 다시 생성됨
# kubectl delete pod sf-nginx-1
pod "sf-nginx-1" deleted
# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
rc-nginx-pgjhj 1/1 Running 0 14m 10.36.0.2 node1.example.com <none> <none>
rc-nginx-st9hl 1/1 Running 0 18m 10.44.0.1 node2.example.com <none> <none>
rc-nginx-xmvns 1/1 Running 0 18m 10.36.0.1 node1.example.com <none> <none>
sf-nginx-0 1/1 Running 0 106s 10.44.0.2 node2.example.com <none> <none>
sf-nginx-1 1/1 Running 0 25s 10.44.0.3 node2.example.com <none> <none>
sf-nginx-2 1/1 Running 0 106s 10.36.0.3 node1.example.com <none> <none>
kubectl scale [object] [pod명] --replicas : object의 replicas 수를 scale하는 명령어
# kubectl scale statefulset sf-nginx --replicas=4
statefulset.apps/sf-nginx scaled
# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
rc-nginx-pgjhj 1/1 Running 0 16m 10.36.0.2 node1.example.com <none> <none>
rc-nginx-st9hl 1/1 Running 0 19m 10.44.0.1 node2.example.com <none> <none>
rc-nginx-xmvns 1/1 Running 0 19m 10.36.0.1 node1.example.com <none> <none>
sf-nginx-0 1/1 Running 0 3m28s 10.44.0.2 node2.example.com <none> <none>
sf-nginx-1 1/1 Running 0 2m7s 10.44.0.3 node2.example.com <none> <none>
sf-nginx-2 1/1 Running 0 3m28s 10.36.0.3 node1.example.com <none> <none>
sf-nginx-3 1/1 Running 0 3s 10.36.0.4 node1.example.com <none> <none>
# kubectl scale statefulset sf-nginx --replicas=2
statefulset.apps/sf-nginx scaled
# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
rc-nginx-pgjhj 1/1 Running 0 16m 10.36.0.2 node1.example.com <none> <none>
rc-nginx-st9hl 1/1 Running 0 20m 10.44.0.1 node2.example.com <none> <none>
rc-nginx-xmvns 1/1 Running 0 20m 10.36.0.1 node1.example.com <none> <none>
sf-nginx-0 1/1 Running 0 3m55s 10.44.0.2 node2.example.com <none> <none>
sf-nginx-1 1/1 Running 0 2m34s 10.44.0.3 node2.example.com <none> <none>
edit 명령어를 이용하여 nginx:1.14 → 1.15 버전 변경
# kubectl edit statefulsets.apps sf-nginx
# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: apps/v1
kind: StatefulSet
metadata:
creationTimestamp: "2022-12-12T12:50:19Z"
generation: 4
name: sf-nginx
namespace: default
resourceVersion: "82038"
uid: 45664fcd-4d16-4d7b-a1ed-3a32cb20c2bb
spec:
podManagementPolicy: Parallel
replicas: 2
revisionHistoryLimit: 10
selector:
matchLabels:
app: webui
serviceName: sf-service
template:
metadata:
creationTimestamp: null
labels:
app: webui
name: nginx-pod
spec:
containers:
- image: nginx:1.15
imagePullPolicy: IfNotPresent
name: nginx-container
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
롤링 업데이트를 진행하여 nginx 버전 업그레이드
# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
rc-nginx-pgjhj 1/1 Running 0 21m 10.36.0.2 node1.example.com <none> <none>
rc-nginx-st9hl 1/1 Running 0 24m 10.44.0.1 node2.example.com <none> <none>
rc-nginx-xmvns 1/1 Running 0 24m 10.36.0.1 node1.example.com <none> <none>
sf-nginx-0 1/1 Running 0 3m6s 10.44.0.2 node2.example.com <none> <none>
sf-nginx-1 1/1 Running 0 3m9s 10.36.0.3 node1.example.com <none> <none>
# kubectl describe pod sf-nginx-0
Name: sf-nginx-0
Namespace: default
Priority: 0
Service Account: default
Node: node2.example.com/10.100.0.102
Start Time: Mon, 12 Dec 2022 21:55:44 +0900
Labels: app=webui
controller-revision-hash=sf-nginx-7c9755b47
statefulset.kubernetes.io/pod-name=sf-nginx-0
Annotations: <none>
Status: Running
IP: 10.44.0.2
IPs:
IP: 10.44.0.2
Controlled By: StatefulSet/sf-nginx
Containers:
nginx-container:
Container ID: containerd://83b5c7e5c4ac31cae16671c63dbc4951cf31a0615b8af90fd5527ba9d99332a5
Image: nginx:1.15
Image ID: docker.io/library/nginx@sha256:23b4dcdf0d34d4a129755fc6f52e1c6e23bb34ea011b315d87e193033bcd1b68
Port: <none>
Host Port: <none>
State: Running
Started: Mon, 12 Dec 2022 21:55:45 +0900
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-xrfrg (ro)
롤백도 가능
# kubectl rollout undo statefulset sf-nginx
statefulset.apps/sf-nginx rolled back
[참고]
- https://www.youtube.com/watch?v=Mx3y9un1KeI
반응형
'Kubernetes' 카테고리의 다른 글
| [Kubernetes] CronJob (0) | 2022.12.13 |
|---|---|
| [Kubernetes] Job Controller (0) | 2022.12.12 |
| [Kubernetes] DaemonSet + RollingUpdate (1) | 2022.12.12 |
| [Kubernetes] RollingUpdate를 위한 Deployment (0) | 2022.12.11 |
| [Kubernetes] ReplicaSet(ReplicationController와의 차이점은?) 쿠버네티스 pod 개수 보장 (0) | 2022.12.05 |