operator:
statefulset:有状态副本集
特点
运行在: 1,稳定且唯一的网络标识符
2，稳定且持久的存储
3，有序，平滑地部署和扩展
4，有序，平滑地删除和终止
5，有序的滚动更新
三个组件:headless service(无头服务), statefuleset,volumeClaimTemplate(存储卷申请模板)
先准备pv
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv001
labels:
name: pv001
polity: fast
spec:
nfs:
path: /data/volumes/v1
server: node2
accessModes: ["ReadWriteMany","ReadWriteOnce"]
capacity:
storage: 5Gi
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv002
labels:
name: pv002
polity: fast
spec:
nfs:
path: /data/volumes/v2
server: node2
accessModes: ["ReadWriteOnce"]
capacity:
storage: 5Gi
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv003
labels:
name: pv003
polity: fast
spec:
nfs:
path: /data/volumes/v3
server: node2
accessModes: ["ReadWriteMany","ReadWriteOnce"]
capacity:
storage: 5Gi
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv004
labels:
name: pv004
polity: fast
spec:
nfs:
path: /data/volumes/v4
server: node2
accessModes: ["ReadWriteMany","ReadWriteOnce"]
capacity:
storage: 10Gi
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv005
labels:
name: pv005
polity: fast
spec:
nfs:
path: /data/volumes/v5
server: node2
accessModes: ["ReadWriteMany","ReadWriteOnce"]
capacity:
storage: 10Gi
kubectl apply -f pv-demo.yaml
kubectl get pv
实例
apiVersion: v1
kind: Service
metadata:
name: myapp-svc service名
labels:
app: myapp
spec:
ports:
- port: 80 service端口
name: web service端口名
clusterIP: None statefulset要求无头服务
selector: 与pod关联的标签
app: myapp-pod
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: myapp statefulset控制器名 创建的pod名也为这个
spec:
serviceName: myapp-svc 关联的service服务名，必须是无头服务
replicas: 2
selector: 管理哪些pod,关联pod的label
matchLabels:
app: myapp-pod
template: 定义pod模板
metadata:
labels: 定义的pod的标签label
app: myapp-pod
spec:
containers:
- name: myapp pod中容器名
image: ikubernetes/myapp:v1
ports:
- containerPort: 80
name: web
volumeMounts:
- name: myappdata 挂载myappdata存储卷
mountPath: /usr/share/nginx/html 容器中挂载的路径
volumeClaimTemplates: pvc模板 为每个pod定义volume 自动创建pvc
- metadata:
name: myappdata 定义的pvc名
spec:
accessModes: ["ReadWriteOnce"] 单路读写
resources: 资源
requests: 请求
storage: 5Gi 大小5Gi存储空间
创建
kubectl explain sts
kubectl apply -f stateful-demo.yaml
验证：
kubectl get sts
kubectl get pvc
kubectl get svc
kubectl get pv
kubectl get pods
删除sts时
逆向删除pod
kubectl delete -f stateful-demo.yaml
删除时pvc还在，且一直保留给固定的pod
statefulset支持滚动更新，规模扩展
逆向更新
dns解析
kubectl exec -it myapp-0 -- /bin/sh
nslookup myapp-3.myapp-svc.default.svc.cluster.local
域名构成 pod名 service名 命名空间 集群域名svc.cluster.local
域名 pod_name.service_name.namaspace_name.svc.cluster.local
nslookup myapp-3.myapp-svc
扩容宿容
kubectl scale sts myapp --replicas=3
kubectl patch sts myapp -p '{"spec":{"replicas":2}}'
更新策略
kubectl explain sts.spec.updateStrategy
kubectl explain sts.spec.updateStrategy.rollingUpdate
分区更新
kubectl explain sts.spec.updateStrategy.rollingUpdate.partition
myapp-0
myapp-1
myapp-2
myapp-3
myapp-4
partition:N
N>=3
即更新3和4，即myapp-3,myapp-4 这叫金丝雀发布
验证
方法一
kubectl patch sts myapp -p '{"spec":{"replicas":5}}'
kubectl patch sts myapp -p '{"spec":{"updateStrategy":{"rollingUpdate":{"partition":4}}}}' 打上补丁 partition>=4
kubectl describe sts myapp 查看更新策略
kubectl set image sts/myapp myapp=ikubernetes/myapp:v2 改变镜像就会更新了
kubectl get sts -o wide
方法二
vim stateful-demo.yaml
kind: StatefulSet
...
spec:
updateStrategy:
rollingUpdate:
partition: 3
kubectl apply -f stateful-demo.yaml
如果版本没问题，就全部更新
vim stateful-demo.yaml
kind: StatefulSet
...
spec:
updateStrategy:
rollingUpdate:
partition: 0
kubectl apply -f stateful-demo.yaml