StatefulSet是一种有状态服务，其存储卷的使用有多种方式：
使用共享存储，这时在模板中定义一个volume卷，可以给多个pod共享；
每个pod配置独立的存储卷，使用非共享存储（块存储）时需要这样配置，通过配置volumeClaimTemplates实现；
对于StatefulSet使用localvolume的场景，和上述两种情况都不一样：
通过volumeClaimTemplates自动生成localvolume的controller没有提供；
localvolume本身定义了节点信息，会导致使用这个pv的pod调度到相应节点；
StatefulSet如果多个pod使用同一个localvolume，会导致多个pod调度到相同节点；
本文先通过手动创建pvc、localvolume的方式，并利用statefulset 自动生成pvc的规则，在statefulset中配置localvolume；
场景：
生成一个StatefulSet应用，每个pod定义到特定节点；StatefulSet中定义2个Pod，每个pod使用两个pvc，共需要创建4个pvc和4个localvolume；
如下图所示：
模板：
下面分别给出4个pv、pvc的模板，4个pv分别配置到cn-shenzhen.i-wz9gvy73m4qyk03xzg1y、cn-shenzhen.i-wz9c9m0m4oldr6mt89rd两个节点上；
pv1, pvc1:
apiVersion: v1
kind: PersistentVolume
metadata:
name: local-volume-a-1
labels:
alicloud-pvname: local-volume-a-1
spec:
capacity:
storage: 20Gi
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
storageClassName: local-volume
local:
path: /local1
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- cn-shenzhen.i-wz9c9m0m4oldr6mt89rd
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: local-volume-a-web-0
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 20Gi
storageClassName: local-volume
selector:
matchLabels:
alicloud-pvname: local-volume-a-1pv2, pvc2:
apiVersion: v1
kind: PersistentVolume
metadata:
name: local-volume-a-2
labels:
alicloud-pvname: local-volume-a-2
spec:
capacity:
storage: 20Gi
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
storageClassName: local-volume
local:
path: /local1
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- cn-shenzhen.i-wz9gvy73m4qyk03xzg1y
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: local-volume-a-web-1
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 20Gi
storageClassName: local-volume
selector:
matchLabels:
alicloud-pvname: local-volume-a-2pv3, pvc3:
apiVersion: v1
kind: PersistentVolume
metadata:
name: local-volume-b-1
labels:
alicloud-pvname: local-volume-b-1
spec:
capacity:
storage: 20Gi
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
storageClassName: local-volume
local:
path: /local2
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- cn-shenzhen.i-wz9c9m0m4oldr6mt89rd
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: local-volume-b-web-0
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 20Gi
storageClassName: local-volume
selector:
matchLabels:
alicloud-pvname: local-volume-b-1pv4, pvc4:
apiVersion: v1
kind: PersistentVolume
metadata:
name: local-volume-b-2
labels:
alicloud-pvname: local-volume-b-2
spec:
capacity:
storage: 20Gi
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
storageClassName: local-volume
local:
path: /local2
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- cn-shenzhen.i-wz9gvy73m4qyk03xzg1y
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: local-volume-b-web-1
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 20Gi
storageClassName: local-volume
selector:
matchLabels:
alicloud-pvname: local-volume-b-2创建上述pv pvc后，创建应用：
创建应用：
创建的时候注意pvc的名字的构成：
pvc的名字 = statefulset-name + volume-name + 序号
local-volume-a-web-0 = "local-volume-a" + "-" + "web" + "-" + "0"
apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
app: nginx
spec:
ports:
- port: 80
name: web
clusterIP: None
selector:
app: nginx
---
apiVersion: apps/v1beta2
kind: StatefulSet
metadata:
name: web
spec:
selector:
matchLabels:
app: nginx
serviceName: "nginx"
replicas: 2
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
name: web
volumeMounts:
- name: local-volume-a
mountPath: /data1
- name: local-volume-b
mountPath: /data2
volumeClaimTemplates:
- metadata:
name: local-volume-a
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: "local-volume"
resources:
requests:
storage: 20Gi
- metadata:
name: local-volume-b
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: "local-volume"
resources:
requests:
storage: 20Gi验证：
# kubectl get pod | grep web
web-0 1/1 Running 0 15m
web-1 1/1 Running 0 14m
# kubectl get pvc | grep local
local-volume-a-web-0 Bound local-volume-a-1 20Gi RWO local-volume 15m
local-volume-a-web-1 Bound local-volume-a-2 20Gi RWO local-volume 15m
local-volume-b-web-0 Bound local-volume-b-1 20Gi RWO local-volume 15m
local-volume-b-web-1 Bound local-volume-b-2 20Gi RWO local-volume 15m
# kubectl get pv | grep local
local-volume-a-1 20Gi RWO Retain Bound default/local-volume-a-web-0 local-volume 15m
local-volume-a-2 20Gi RWO Retain Bound default/local-volume-a-web-1 local-volume 17m
local-volume-b-1 20Gi RWO Retain Bound default/local-volume-b-web-0 local-volume 15m
local-volume-b-2 20Gi RWO Retain Bound default/local-volume-b-web-1 local-volume 17m删除pod，验证新建pod调度到相同节点：
# kubectl describe pod web-0 | grep Node
Node: cn-shenzhen.i-wz9c9m0m4oldr6mt89rd/192.168.0.12
Node-Selectors: <none>
# kubectl delete pod web-0
pod "web-0" deleted
# kubectl get pod
NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 10s
web-1 1/1 Running 0 15m
# kubectl describe pod web-0 | grep Node
Node: cn-shenzhen.i-wz9c9m0m4oldr6mt89rd/192.168.0.12
Node-Selectors: <none>
