一：Statefulset
StatefulSet是为了解决有状态服务的问题，对应的Deployment和ReplicaSet是为了无状态服务而设计，其应用场景包括：
1.稳定的持久化存储，即Pod重新调度后还是能访问到相同的持久化数据，基于PVC来实现
2.稳定的网络标志，即Pod重新调度后其PodName和HostName不变，基于Headless Service（即没有Cluster IP的Service）来实现
3.有序部署，有序扩展，即Pod是有顺序的，在部署或者扩展的时候要依据定义的顺序依次依次进行（即从0到N-1，在下一个Pod运行之前所有之前的Pod必须都是Running和Ready状态），基于init containers来实现
4.有序收缩，有序删除（即从N-1到0）因为statefulset要求Pod的名称是有顺序的，每一个Pod都不能被随意取代，也就是即使Pod重建之后，名称依然不变。为后端的每一个Pod去命名。
从上面的应用场景可以发现，StatefulSet由以下几部分组成：
1.用于定义网络标志的Headless Service（headless-svc：无头服务。因为没有IP地址，所以它不具备负载均衡的功能了。）
2.用于创建PersistentVolumes的volumeClaimTemplates
3.定义具体应用的StatefulSetStatefulSet：Pod控制器。
RC、RS、Deployment、DS。 无状态的服务。
template（模板）：根据模板创建出来的Pod，它们的状态都是一模一样的（除了名称、IP、域名之外）
可以理解为：任何一个Pod，都可以被删除，然后用新生成的Pod进行替换。有状态的服务：需要记录前一次或者多次通信中的相关时间，以作为下一次通信的分类标准。比如：MySQL等数据库服务。（Pod的名称，不能随意变化。数据持久化的目录也是不一样，每一个Pod都有自己独有的数据持久化存储目录。）
每一个Pod-----对应一个PVC-----每一个PVC对应一个PV。
测试：要求
二、以自己的名称创建一个名称空间，以下所有资源都运行在此空间中。
用statefuset资源运行一个httpd web服务，要求3个Pod，但是每个Pod的主界面内容不一样，并且都要做专有的数据持久化，尝试删除其中一个Pod，查看新生成的Pod，是否数据与之前一致。
1.基于NFS服务，创建NFS服务。
1.[[email protected]?~]#?yum?-y?install?nfs-utils?rpcbind??br/>2.[[email protected]?~]#?mkdir?/nfsdata??
3.[[email protected]?~]#?vim?/etc/exports??br/>4./nfsdata??*(rw,sync,no_root_squash)??
5.[[email protected]?~]#?systemctl?start?nfs-server.service???
6.[[email protected]?~]#?systemctl?start?rpcbind??br/>7.[[email protected]?~]#?showmount?-e??
8.Export?list?for?master:??
9./nfsdata?*??
2.创建RBAC权限
vim rbac-rolebind.yaml
apiVersion: v1
kind: Namespace
metadata:
name: lbs-test
apiVersion: v1
kind: ServiceAccount 创建rbac授权用户。及定义权限
metadata:
name: nfs-provisioner
name：lbs-test
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: nfs-provisioner-runner
name：lbs-test
rules:
- apiGroups: [""]
resources: ["persistentvolumes"]
verbs: ["get", "list", "watch", "create", "delete"]
- apiGroups: [""]
resources: ["persistentvolumeclaims"]
verbs: ["get", "list", "watch", "update"]
- apiGroups: ["storage.k8s.io"]
resources: ["storageclasses"]
verbs: ["get", "list", "watch"]
- apiGroups: [""]
resources: ["events"]
verbs: ["watch", "create", "update", "patch"]
- apiGroups: [""]
resources: ["services", "endpoints"]
verbs: ["get","create","list", "watch","update"]
- apiGroups: ["extensions"]
resources: ["podsecuritypolicies"]
resourceNames: ["nfs-provisioner"]
verbs: ["use"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: run-nfs-provisioner
subjects:
- kind: ServiceAccount
name: nfs-provisioner
namespace: lbs-test 如没有名称空间需要添加这个default默认否则报错
roleRef:
kind: ClusterRole
name: nfs-provisioner-runner
apiGroup: rbac.authorization.k8s.io执行yaml文件：
1.[[email protected]?yaml]#?kubectl?apply?-f?rbac-rolebind.yaml???
2.namespace/lbh-test?created??
3.serviceaccount/nfs-provisioner?created??
4.clusterrole.rbac.authorization.k8s.io/nfs-provisioner-runner?created??
5.clusterrolebinding.rbac.authorization.k8s.io/run-nfs-provisioner?created??
3.创建Deployment资源对象。
[[email protected] yaml]# vim nfs-deployment.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: nfs-client-provisioner
name：lbs-test
spec:
replicas: 1#副本数量为1
strategy:
type: Recreate#重置
template:
metadata:
labels:
app: nfs-client-provisioner
spec:
serviceAccount: nfs-provisioner#指定账户
containers:
- name: nfs-client-provisioner
image: registry.cn-hangzhou.aliyuncs.com/open-ali/nfs-client-provisioner使用的是这个镜像。
volumeMounts:
- name: nfs-client-root
mountPath: /persistentvolumes#指定容器内的挂载目录
env:
- name: PROVISIONER_NAME#容器内置变量
value: bdqn#这是变量的名字
- name: NFS_SERVER
value: 192.168.1.1
- name: NFS_PATH#指定Nfs的共享目录
value: /nfsdata
volumes:#指定挂载到容器内的nfs路径与IP
- name: nfs-client-root
nfs:
server: 192.168.1.1
path: /nfsdata执行yaml文件，查看Pod：br/>1.[[email protected]?yaml]#?kubectl?apply?-f?nfs-deployment.yaml???
2.deployment.extensions/nfs-client-provisioner?created???br/>3.[[email protected]?yaml]#?kubectl?get?pod?-n?lbs-test???
4.NAME??????????????????????????????????????READY???STATUS????RESTARTS???AGE??
5.nfs-client-provisioner-5d88975f6d-wdbnc???1/1?????Running???0??????????13s??
4.创建Storageclass资源对象（sc）：
[email protected] yaml]# vim sc.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: sc-nfs
namespace：lbs-test #名称空间 名
provisioner: lbs-test#与deployment资源的env环境变量value值相同
reclaimPolicy: Retain #回收策略执行yaml文件，查看SC：br/>1.[[email protected]?yaml]#?kubectl?apply?-f?sc.yaml???
2.storageclass.storage.k8s.io/sc-nfs?created??br/>3.[[email protected]?yaml]#?kubectl?get?sc?-n?lbs-test???
4.NAME?????PROVISIONER???AGE??
5.sc-nfs???lbs-test??????8s??
5.创建StatefulSet资源对象，自动创建PVC：
vim statefulset.yaml
apiVersion: v1
kind: Service
metadata:
name: headless-svc
namespace: lbs-test
labels:
app: headless-svc
spec:
ports:
- port: 80
name: myweb
selector:
app: headless-pod
clusterIP: None
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: statefulset-test
namespace: lbs-test
spec:
serviceName: headless-svc
replicas: 3
selector:
matchLabels:
app: headless-pod
template:
metadata:
labels:
app: headless-pod
spec:
containers:
- image: httpd
name: myhttpd
ports:
- containerPort: 80
name: httpd
volumeMounts:
- mountPath: /mnt
name: test
volumeClaimTemplates: 这个字段：自动创建PVC
- metadata:
name: test
annotations: //这是指定storageclass，名称要一致
volume.beta.kubernetes.io/storage-class: sc-nfs
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 100Mi执行yaml文件，查看Pod：br/>1.[[email protected]?yaml]#?kubectl?apply?-f?statefulset.yaml???
2.service/headless-svc?created??br/>3.statefulset.apps/statefulset-test?created??
4.[[email protected]?yaml]#?kubectl?get?pod?-n?lbs-test???
5.NAME??????????????????????????????????????READY???STATUS????RESTARTS???AGE??
6.nfs-client-provisioner-5d88975f6d-wdbnc???1/1?????Running???0??????????22m??
7.statefulset-test-0????????????????????????1/1?????Running???0??????????8m59s??
8.statefulset-test-1????????????????????????1/1?????Running???0??????????2m30s??
9.statefulset-test-2????????????????????????1/1?????Running???0??????????109s??
**查看是否自动创建PV及PVC**
PV：
1.[[email protected]?yaml]#?kubectl?get?pv?-n?lbs-test???
2.NAME???????????????????????????????????????CAPACITY???ACCESS?MODES???RECLAIM?POLICY???STATUS???CLAIM??????????????????????????????STORAGECLASS???REASON???AGE??
3.pvc-0454e9ad-892f-4e39-8dcb-79664f65d1e5???100Mi??????RWO????????????Delete???????????Bound????lbh-test/test-statefulset-test-2???sc-nfs??????????????????4m23s??
4.pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5???100Mi??????RWO????????????Delete???????????Bound????lbh-test/test-statefulset-test-0???sc-nfs??????????????????11m??
5.pvc-99137753-ccd0-4524-bf40-f3576fc97eba???100Mi??????RWO????????????Delete???????????Bound????lbh-test/test-statefulset-test-1???sc-nfs??????????????????5m4s??
PVC：
1.[[email protected]?yaml]#?kubectl?get?pvc?-n?lbs-test???
2.NAME??????????????????????STATUS???VOLUME?????????????????????????????????????CAPACITY???ACCESS?MODES???STORAGECLASS???AGE??
3.test-statefulset-test-0???Bound????pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5???100Mi??????RWO????????????sc-nfs?????????13m??
4.test-statefulset-test-1???Bound????pvc-99137753-ccd0-4524-bf40-f3576fc97eba???100Mi??????RWO????????????sc-nfs?????????6m42s??
5.test-statefulset-test-2???Bound????pvc-0454e9ad-892f-4e39-8dcb-79664f65d1e5???100Mi??????RWO????????????sc-nfs?????????6m1s??
查看是否创建持久化目录：
1.[[email protected]?yaml]#?ls?/nfsdata/??
2.lbh-test-test-statefulset-test-0-pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5??
3.lbh-test-test-statefulset-test-1-pvc-99137753-ccd0-4524-bf40-f3576fc97eba??
4.lbh-test-test-statefulset-test-2-pvc-0454e9ad-892f-4e39-8dcb-79664f65d1e5??
6.在pod资源内创建数据。并访问测试。
1.[[email protected]?yaml]#?cd?/nfsdata/??
2.[[email protected]?nfsdata]#?echo?111?>?lbs-test-test-statefulset-test-0-pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5/index.html??
3.[[email protected]?nfsdata]#?echo?222?>?lbs-test-test-statefulset-test-1-pvc-99137753-ccd0-4524-bf40-f3576fc97eba/index.html??
4.[[email protected]?nfsdata]#?echo?333?>?lbs-test-test-statefulset-test-2-pvc-0454e9ad-892f-4e39-8dcb-79664f65d1e5/index.html??
5.[[email protected]?nfsdata]#?kubectl?get?pod?-o?wide?-n?lbs-test???
6.NAME??????????????????????????????????????READY???STATUS????RESTARTS???AGE?????IP???????????NODE?????NOMINATED?NODE???READINESS?GATES??
7.nfs-client-provisioner-5d88975f6d-wdbnc???1/1?????Running???0??????????30m?????10.244.2.2???node02???<none>???????????<none>??
8.statefulset-test-0????????????????????????1/1?????Running???0??????????17m?????10.244.1.2???node01???<none>???????????<none>??
9.statefulset-test-1????????????????????????1/1?????Running???0??????????10m?????10.244.2.3???node02???<none>???????????<none>??
10.statefulset-test-2????????????????????????1/1?????Running???0??????????9m57s???10.244.1.3???node01???<none>???????????<none>??
11.[[email protected]?nfsdata]#?curl?10.244.1.2??
12.111??
13.[[email protected]?nfsdata]#?curl?10.244.2.3??
14.222??
15.[[email protected]?nfsdata]#?curl?10.244.1.3??
16.333??7.删除其中一个pod，查看该pod资源的数据是否会**重新创建并存在。**
1.[[email protected]?~]#?kubectl?get?pod?-n?lbs-test???
2.NAME??????????????????????????????????????READY???STATUS????RESTARTS???AGE??
3.nfs-client-provisioner-5d88975f6d-wdbnc???1/1?????Running???0??????????33m??
4.statefulset-test-0????????????????????????1/1?????Running???0??????????20m??
5.statefulset-test-1????????????????????????1/1?????Running???0??????????13m??
6.statefulset-test-2????????????????????????1/1?????Running???0??????????13m??
7.[[email protected]?~]#?kubectl?delete?pod?-n?lbs-test?statefulset-test-0???
8.pod?"statefulset-test-0"?deleted??
**9.??删除后会重新创建pod资源**
10.[[email protected]?~]#?kubectl?get?pod?-n?lbs-test?-o?wide??
11.NAME??????????????????????????????????????READY???STATUS????RESTARTS???AGE???IP???????????NODE?????NOMINATED?NODE???READINESS?GATES??
12.nfs-client-provisioner-5d88975f6d-wdbnc???1/1?????Running???0??????????35m???10.244.2.2???node02???<none>???????????<none>??
13.statefulset-test-0????????????????????????1/1?????Running???0??????????51s???10.244.1.4???node01???<none>???????????<none>??
14.statefulset-test-1????????????????????????1/1?????Running???0??????????15m???10.244.2.3???node02???<none>???????????<none>??
15.statefulset-test-2????????????????????????1/1?????Running???0??????????14m???10.244.1.3???node01???<none>???????????<none>??
**数据依旧存在。**
16.[[email protected]?~]#?curl?10.244.1.4??
17.111??
18.[[email protected]?~]#?cat?/nfsdata/lbs-test-test-statefulset-test-0-pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5/index.html???
19.111??StatefulSet资源对象，针对有状态的服务的数据持久化测试完成。
通过测试，即使删除Pod，重新生成调度后，依旧能访问到之前的持久化数据。
k8s数据持久化之statefulset的数据持久化，并自动创建PV与PVC
原文地址：https://blog.51cto.com/13911055/2473402