Topology Aware
對於雲盤這種存儲卷類型,只能在相同zone的ecs上進行掛載,在多可用區的集羣環境中,就需要對pv、pvc和pod進行一致性zone調度;
1. 傳統使用方式:
通過PV、PVC所在zoneid信息,把pod調度到相應zone;
即在PV中定義相應的zoneid信息,當一個pod使用這個pv的時候,scheduler會根據pv的zoneid把pod調度到相應可用區;
具體配置:
apiVersion: v1
kind: PersistentVolume
metadata:
labels:
failure-domain.beta.kubernetes.io/region: cn-beijing
failure-domain.beta.kubernetes.io/zone: cn-beijing-e
name: d-2ze6wbcvihjeaw5bae0c
spec:
accessModes:
- ReadWriteOnce
capacity:
storage: 20Gi
csi:
driver: diskplugin.csi.alibabacloud.com
volumeHandle: d-bp1fqy1enb2rtymx5g5y
persistentVolumeReclaimPolicy: Delete
storageClassName: alicloud-disk-ssd
通過在PV中添加下面label來完成調度:
labels:
failure-domain.beta.kubernetes.io/region: cn-beijing
failure-domain.beta.kubernetes.io/zone: cn-beijing-e
2. 通過Topology Aware方式
上述方式需要先確定雲盤的可用區,然後與pod進行關聯調度。
而Topology Aware方式是雲盤根據pod所在的zone進行創建。
使用下面storageclass,WaitForFirstConsumer配置會使pv controller在pod啓動的時候去創建pv,並通過pod所在的zone信息來確定pv所在的zone。
kind: StorageClass
apiVersion: storage.k8s.io/v1beta1
metadata:
name: alicloud-disk-aware
provisioner: diskplugin.csi.alibabacloud.com
volumeBindingMode: WaitForFirstConsumer
parameters:
type: cloud_ssd
環境準備
集羣創建、依賴配置、CSI插件部署等請參考:CSI部署詳解
創建StorageClass
WaitForFirstConsumer:表示只有pod消費這個pvc的時候才驅動Provisioner進行pv創建;
kind: StorageClass
apiVersion: storage.k8s.io/v1beta1
metadata:
name: alicloud-disk-aware
provisioner: diskplugin.csi.alibabacloud.com
volumeBindingMode: WaitForFirstConsumer
parameters:
type: cloud_ssd
創建動態PVC PV
通過下面模板創建動態卷PV:
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: disk-pvc
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 25Gi
storageClassName: alicloud-disk-aware
# kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
disk-pvc Pending alicloud-disk-aware 23m
創建應用
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-disk
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.7.9
ports:
- containerPort: 80
volumeMounts:
- name: disk-pvc
mountPath: "/data"
volumes:
- name: disk-pvc
persistentVolumeClaim:
claimName: disk-pvc
驗證掛載、高可用
查看pvc已經綁定完成
# kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
disk-pvc Bound pvc-bf7732a6-a7cf-11e9-8dec-00163e0a6ecc 25Gi RWO alicloud-disk-aware 18s
# kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-bf7732a6-a7cf-11e9-8dec-00163e0a6ecc 25Gi RWO Delete Bound default/disk-pvc alicloud-disk-aware 7s
查看pvc詳情,volume.kubernetes.io/selected-node即爲pv的調度信息:
# kubectl describe pvc disk-pvc
Name: disk-pvc
Namespace: default
StorageClass: alicloud-disk-aware
Status: Bound
Volume: pvc-bf7732a6-a7cf-11e9-8dec-00163e0a6ecc
Labels: <none>
Annotations: pv.kubernetes.io/bind-completed: yes
pv.kubernetes.io/bound-by-controller: yes
volume.beta.kubernetes.io/storage-provisioner: diskplugin.csi.alibabacloud.com
volume.kubernetes.io/selected-node: cn-hangzhou.192.168.6.149
Finalizers: [kubernetes.io/pvc-protection]
Capacity: 25Gi
Access Modes: RWO
VolumeMode: Filesystem
查看pod,驗證雲盤掛載成功,創建測試文件;
# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-disk-6d5659d745-2ts26 1/1 Running 0 2m1s
# kubectl exec nginx-disk-6d5659d745-2ts26 ls /data
lost+found
# kubectl exec nginx-disk-6d5659d745-2ts26 touch /data/test
# kubectl exec nginx-disk-6d5659d745-2ts26 ls /data
lost+found
test
刪除Pod,查看重建Pod是否數據穩定;
# kubectl delete pod nginx-disk-6d5659d745-2ts26
pod "nginx-disk-6d5659d745-2ts26" deleted
# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-disk-6d5659d745-m5z9p 1/1 Running 0 11s
# kubectl exec nginx-disk-6d5659d745-m5z9p ls /data
lost+found
test