12.kubernetes笔记 Volume存储卷(三) Longhorn Storageclass 动态预配存储空间
Bigyong -
前面介绍的PV、PVC完成了存储类型和Pod挂载的解耦，开发人员直接使用PVC，而Volume存储系统的PV由管理员维护，但随之带来的问题，开发人员使用PVC之前，需要系统管理员提前手动创建PV，而随着pod的不断增多，系统管理员的工作会变得重复和繁琐，静态供给方式这并不符合自动化运维的趋势，随之应运而生的Storageclass 动态预配存储空间，它的作用就是创建PV的模板,解决了PV的自动创建，备份等扩展功能.
Storageclass简介简称SC;PV和PVC都可属于某个特定的SC;
创建PV的模板:可以将某个存储服务与SC关联起来，并且将该存储服务的管理接口提供给SC，从而让SC能够在存储服务上CRUD(create、Read.Update和Delete)存储单元;因而，在同一个SC上声明PVC时，若无现存可匹配的PV，则SC能够调用管理接口直接创建出一个符合PVC声明的需求的PV来。这种PV的提供机制，就称为Dynamic Provision.
具体来说，StorageClass会定义一下两部分：
PV的属性 ，比如存储的大小、类型等；创建这种PV需要使用到的存储插件，比如Ceph等；有了这两部分信息，Kubernetes就能够根据用户提交的PVC，找到对应的StorageClass，然后Kubernetes就会调用 StorageClass声明的存储插件，创建出需要的PV。
这里需要注意的是这么多种存储系统并不是所有的存储系统都支持StorageClass,它需要你的存储系统提供某种接口来让controller可以调用并传递进去PVC的参数去创建PV
常用字段:StorageClass资源的期望状态直接与apiversion、kind和metadata定义于同一级别而无须嵌套于spec字段中，它支持使用的字段包括如下几个
allowVolumeExpansion <boolean>:是否支持存储卷空间扩展功能;allowedTopologies <[]0bject>:定义可以动态配置存储卷的节点拓扑，仅启用了卷调度功能的服务器才会用到该字段;每个卷插件都有自己支持的拓扑规范，空的拓扑选择器表示无拓扑限制;provisioner <strinp>:必选字段，用于指定存储服务方(provisioner，或称为预备器)，存储类要依赖该字段值来判定要使用的存储插件以便适配到目标存储系统;kubernetes内建支持许多的Provisioner，它们的名字都以kubernetes.io/为前缀，例如kubernetes.io/glusterfs等;parameters <map[string]stringp: 定义连接至指定的Provisioner类别下的某特定存储时需要使用的各相关参数;不同Provisioner的可用的参数各不相同;reclaimPolicy <strinp:由当前存储类动态创建约PV资源的默认回收策路，可用值为Delete(默认)和Retain两个;但那些静态FV的回收策略则取决于它们自身的定义;volumeBindingMlode <string>:定义如何为PVC完成预配和绑定，默认值为VolumeBindingImmediate;该字段仅在启用了存储卷调度功能时才能生效;mountoptions<[]string>:由当前类动态创建的PV资源的默认挂载选项列表。模板示例:[root@k8s-master storage]# cat Storageclass-rdb-demo.yaml
apiversion: storage.k8s.io/v1
kind: Storageclass
metadata:
name: fast-rbd
provisioner: kubernetes.io/rbd #不同的存储后端 parameters模板各不一样 需要查阅官方文档 这里是ceph的 也不是所有的存储类型都是支持Storageclass
parameters:
monitors: ceph01.ilinux.io:6789,ceph02.ilinux.io:6789,ceph03.ilinux.io:6789
adminId: admin
adminSecretName: ceph-admin-secret
adminSecretNamespace: kube-system
pool: kube
userId: kube
userSecretName: ceph-kube-secret
userSecretNamespace: kube-system
fsType: ext4
imageFormat: "2"
imageFeatures: "layering"
reclaimPolicy: Retain #回收策略官方文档: https://longhorn.io
Longhorn极大地提升了开发人员和ITOps的效率，仅需点击一下鼠标，即可轻松实现持久化存储，并且无需为专有解决方案支付昂贵的费用。除此之外，Longhorn减少了管理数据及操作环境所需的资源，从而帮助企业更加专注且快速地交付代码及应用程序。
Longhorn依旧秉承Rancher 100%开源的产品理念，它是一个使用微服务构建的分布式块存储项目。2019年，Longhorn发布Beta版本，并于同年10月作为沙箱（Sandbox）项目捐献给CNCF。Longhorn受到了开发者们的广泛关注，成千上万名用户对其进行了压力测试，并提供了极为宝贵的反馈意见。
Longhorn的GA版本提供了一系列功能丰富的企业级存储功能，包括：
自动配置，快照，备份和恢复零中断卷扩容具有定义的RTO和RPO的跨集群灾难恢复卷在不影响卷的情况下实时升级全功能的Kubernetes CLI集成和独立的用户界面
安装准备:节点数至少为3台 要选择leader
[root@k8s-master storage]# yum -y install iscsi-initiator-utils #安装前需要安装ISCSI
[root@k8s-master storage]# kubectl apply -f https://raw.githubusercontent.com/longhorn/longhorn/v1.1.2/deploy/longhorn.yaml #安装 因为要下载镜像 需要等待一些时间
[root@k8s-master storage]# kubectl get pods -n longhorn-system --watch #等待所有pod就绪
[root@k8s-master storage]# kubectl get pods --namespace longhorn-system -o wide #所有pod就绪
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
csi-attacher-54c7586574-fvv4p 1/1 Running 0 37m 10.244.3.16 k8s-node3 <none> <none>
csi-attacher-54c7586574-swdsr 1/1 Running 0 43m 10.244.2.111 k8s-node2 <none> <none>
csi-attacher-54c7586574-zkzrg 1/1 Running 0 43m 10.244.3.10 k8s-node3 <none> <none>
csi-provisioner-5ff5bd6b88-bs687 1/1 Running 0 37m 10.244.3.17 k8s-node3 <none> <none>
csi-provisioner-5ff5bd6b88-gl4xn 1/1 Running 0 43m 10.244.2.112 k8s-node2 <none> <none>
csi-provisioner-5ff5bd6b88-qkzt4 1/1 Running 0 43m 10.244.3.11 k8s-node3 <none> <none>
csi-resizer-7699cdfc4-4w49w 1/1 Running 0 37m 10.244.3.15 k8s-node3 <none> <none>
csi-resizer-7699cdfc4-l2j49 1/1 Running 0 43m 10.244.3.12 k8s-node3 <none> <none>
csi-resizer-7699cdfc4-sndlm 1/1 Running 0 43m 10.244.2.113 k8s-node2 <none> <none>
csi-snapshotter-8f58f46b4-6s89m 1/1 Running 0 37m 10.244.2.119 k8s-node2 <none> <none>
csi-snapshotter-8f58f46b4-qgv5r 1/1 Running 0 43m 10.244.3.13 k8s-node3 <none> <none>
csi-snapshotter-8f58f46b4-tf5ls 1/1 Running 0 43m 10.244.2.115 k8s-node2 <none> <none>
engine-image-ei-a5a44787-5ntlm 1/1 Running 0 44m 10.244.1.146 k8s-node1 <none> <none>
engine-image-ei-a5a44787-h45hr 1/1 Running 0 44m 10.244.3.6 k8s-node3 <none> <none>
engine-image-ei-a5a44787-phnjf 1/1 Running 0 44m 10.244.2.108 k8s-node2 <none> <none>
instance-manager-e-4384d6f1 1/1 Running 0 44m 10.244.2.110 k8s-node2 <none> <none>
instance-manager-e-54f46256 1/1 Running 0 34m 10.244.1.148 k8s-node1 <none> <none>
instance-manager-e-e008dd8a 1/1 Running 0 44m 10.244.3.7 k8s-node3 <none> <none>
instance-manager-r-0ad3175d 1/1 Running 0 44m 10.244.3.8 k8s-node3 <none> <none>
instance-manager-r-61277092 1/1 Running 0 44m 10.244.2.109 k8s-node2 <none> <none>
instance-manager-r-d8a9eb0e 1/1 Running 0 34m 10.244.1.149 k8s-node1 <none> <none>
longhorn-csi-plugin-5htsd 2/2 Running 0 7m41s 10.244.2.123 k8s-node2 <none> <none>
longhorn-csi-plugin-hpjgl 2/2 Running 0 16s 10.244.1.151 k8s-node1 <none> <none>
longhorn-csi-plugin-wtkcj 2/2 Running 0 43m 10.244.3.14 k8s-node3 <none> <none>
longhorn-driver-deployer-5479f45d86-l4fpq 1/1 Running 0 57m 10.244.3.4 k8s-node3 <none> <none>
longhorn-manager-dgk4d 1/1 Running 1 57m 10.244.1.145 k8s-node1 <none> <none>
longhorn-manager-hb7cl 1/1 Running 0 57m 10.244.2.107 k8s-node2 <none> <none>
longhorn-manager-xrxll 1/1 Running 0 57m 10.244.3.3 k8s-node3 <none> <none>
longhorn-ui-79f8976fbf-sb79r 1/1 Running 0 57m 10.244.3.5 k8s-node3 <none> <none>[root@k8s-master storage]# cat pvc-dyn-longhorn-demo.yaml
apiVersion: v1
kind: PersistentVolumeClaim #资源类型
metadata:
name: pvc-dyn-longhorn-demo
namespace: default
spec:
accessModes: ["ReadWriteOnce"]
volumeMode: Filesystem
resources:
requests:
storage: 2Gi #新的PV会以最低容量创建PV
limits:
storage: 10Gi
storageClassName: longhorn #选择longhorn创造
[root@k8s-master storage]# kubectl apply -f longhorn.yaml 修改回收策略及副本数 非必要操作 根据实际需要修改
[root@k8s-master storage]# kubectl get sc
NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE
longhorn driver.longhorn.io Delete(注意回收策略 是删除会有风险) Immediate true 48s
[root@k8s-master storage]# vim longhorn.yaml #修改回收策略 修改yaml文件
---
apiVersion: v1
kind: ConfigMap
metadata:
name: longhorn-storageclass
namespace: longhorn-system
data:
storageclass.yaml: |
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: longhorn
provisioner: driver.longhorn.io #这个是longhorn自定义的provisioner 存储在本地,如果有网络存储按自己需求修改
allowVolumeExpansion: true
reclaimPolicy: Delete
volumeBindingMode: Immediate
parameters:
numberOfReplicas: "3" #数据副本数 副本数越多数据当然会越安全,但同时的磁盘容量和性能要求也会更高
staleReplicaTimeout: "2880"
fromBackup: ""
reclaimPolicy: Retain #添加字段 修改回收策略
...
---
[root@k8s-master storage]# kubectl apply -f longhorn.yaml #重新应用配置
[root@k8s-master storage]# kubectl delete -f pvc-dyn-longhorn-demo.yaml
[root@k8s-master storage]# kubectl apply -f pvc-dyn-longhorn-demo.yaml #重启创建Pod
[root@k8s-master storage]# kubectl get sc #修改成功
NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE
longhorn driver.longhorn.io Retain Immediate true 10m
[root@k8s-master storage]# kubectl get pv #自动创建PV
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pv-nfs-demo002 10Gi RWX Retain Available 2d5h
pv-nfs-demo003 1Gi RWO Retain Available 2d5h
pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58 2Gi RWO Retain Bound default/pvc-dyn-longhorn-demo longhorn 118s
[root@k8s-master storage]# kubectl get pvc #自动创建PVC
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
pvc-dyn-longhorn-demo Bound pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58 2Gi RWO longhorn 2m19s[root@k8s-master ~]# kubectl get svc --namespace longhorn-system -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
csi-attacher ClusterIP 10.102.194.8 <none> 12345/TCP 17h app=csi-attacher
csi-provisioner ClusterIP 10.99.37.10 <none> 12345/TCP 17h app=csi-provisioner
csi-resizer ClusterIP 10.111.56.226 <none> 12345/TCP 17h app=csi-resizer
csi-snapshotter ClusterIP 10.110.198.133 <none> 12345/TCP 17h app=csi-snapshotter
longhorn-backend ClusterIP 10.106.163.23 <none> 9500/TCP 17h app=longhorn-manager
longhorn-frontend ClusterIP 10.111.219.113 <none> 80/TCP 17h app=longhorn-ui #修改SVC为NodePort
[root@k8s-master ~]# kubectl edit svc longhorn-frontend --namespace longhorn-system
service/longhorn-frontend edited
[root@k8s-master ~]# kubectl get svc --namespace longhorn-system -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
csi-attacher ClusterIP 10.102.194.8 <none> 12345/TCP 17h app=csi-attacher
csi-provisioner ClusterIP 10.99.37.10 <none> 12345/TCP 17h app=csi-provisioner
csi-resizer ClusterIP 10.111.56.226 <none> 12345/TCP 17h app=csi-resizer
csi-snapshotter ClusterIP 10.110.198.133 <none> 12345/TCP 17h app=csi-snapshotter
longhorn-backend ClusterIP 10.106.163.23 <none> 9500/TCP 17h app=longhorn-manager
longhorn-frontend NodePort 10.111.219.113 <none> 80:30745/TCP 17h app=longhorn-ui #使用节点IP打开 节点:30745
可以打开UI 查看到现有的卷、创建新卷、查看节点信息、备份等
[root@k8s-master storage]# cat volumes-pvc-longhorn-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: volumes-pvc-longhorn-demo
namespace: default
spec:
containers:
- name: redis
image: redis:alpine
imagePullPolicy: IfNotPresent
ports:
- containerPort: 6379
name: redisport
volumeMounts:
- mountPath: /data
name: redis-data-vol
volumes:
- name: redis-data-vol
persistentVolumeClaim:
claimName: pvc-dyn-longhorn-demo #使用sc创建的pvc
[root@k8s-master storage]# kubectl apply -f volumes-pvc-longhorn-demo.yaml
[root@k8s-master storage]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
centos-deployment-66d8cd5f8b-95brg 1/1 Running 0 18h 10.244.2.117 k8s-node2 <none> <none>
my-grafana-7d788c5479-bpztz 1/1 Running 0 18h 10.244.2.120 k8s-node2 <none> <none>
volumes-pvc-longhorn-demo 1/1 Running 0 2m30s 10.244.1.172 k8s-node1 <none> <none>
[root@k8s-master storage]# kubectl exec volumes-pvc-longhorn-demo -it -- /bin/sh
/data # redis-cli
127.0.0.1:6379> set mykey www.qq.com
OK
127.0.0.1:6379> bgsabe
(error) ERR unknown command `bgsabe`, with args beginning with:
127.0.0.1:6379> bgsave
Background saving started
127.0.0.1:6379> exit
/data # ls
dump.rdb lost+found
/data # exit
[root@k8s-master storage]# kubectl delete -f volumes-pvc-longhorn-demo.yaml
pod "volumes-pvc-longhorn-demo" deleted
[root@k8s-master storage]# cat volumes-pvc-longhorn-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: volumes-pvc-longhorn-demo
namespace: default
spec:
nodeName: k8s-node2 #指定运行节点
containers:
- name: redis
image: redis:alpine
imagePullPolicy: IfNotPresent
ports:
- containerPort: 6379
name: redisport
volumeMounts:
- mountPath: /data
name: redis-data-vol
volumes:
- name: redis-data-vol
persistentVolumeClaim:
claimName: pvc-dyn-longhorn-demo
[root@k8s-master storage]# kubectl get pod -o wide -w
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
centos-deployment-66d8cd5f8b-95brg 1/1 Running 0 18h 10.244.2.117 k8s-node2 <none> <none>
my-grafana-7d788c5479-bpztz 1/1 Running 0 18h 10.244.2.120 k8s-node2 <none> <none>
volumes-pvc-longhorn-demo 1/1 Running 0 68s 10.244.2.124 k8s-node2 <none> <none>
[root@k8s-master storage]# kubectl exec volumes-pvc-longhorn-demo -it -- /bin/sh #查看pvc数据
/data # redis-cli
127.0.0.1:6379> get mykey
"www.qq.com"
127.0.0.1:6379> exit
/data # exit
[root@k8s-node1 ~]# ls /var/lib/longhorn/replicas/ #默认的数据保存路径
pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-da2330a2
[root@k8s-node1 ~]# ls /var/lib/longhorn/replicas/pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-da2330a2/
revision.counter volume-head-000.img volume-head-000.img.meta volume.meta
[root@k8s-node2 ~]# ls /var/lib/longhorn/replicas/
pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-83f7f58c
[root@k8s-node2 ~]# ls /var/lib/longhorn/replicas/pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-83f7f58c/
revision.counter volume-head-000.img volume-head-000.img.meta volume.meta
[root@k8s-node3 ~]# ls /var/lib/longhorn/replicas/
pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-c90965c0
[root@k8s-node3 ~]# ls /var/lib/longhorn/replicas/pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-c90965c0/
revision.counter volume-head-000.img volume-head-000.img.meta volume.meta
[root@k8s-master storage]# kubectl api-resources --api-group=longhorn.io #longhorn自定义的资源类型
NAME SHORTNAMES APIGROUP NAMESPACED KIND
backingimagemanagers lhbim longhorn.io true BackingImageManager
backingimages lhbi longhorn.io true BackingImage
engineimages lhei longhorn.io true EngineImage
engines lhe longhorn.io true Engine
instancemanagers lhim longhorn.io true InstanceManager
nodes lhn longhorn.io true Node
replicas lhr longhorn.io true Replica
settings lhs longhorn.io true Setting
sharemanagers lhsm longhorn.io true ShareManager
volumes lhv longhorn.io true Volume
[root@k8s-master storage]# kubectl get replicas -n longhorn-system
NAME STATE NODE DISK INSTANCEMANAGER IMAGE AGE
pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-r-08f28c21 running k8s-node3 49846d34-b5a8-4a86-96f4-f0d7ca191f2a instance-manager-r-0ad3175d longhornio/longhorn-engine:v1.1.2 3h54m
pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-r-6694fc48 running k8s-node2 ce1ed80b-43c9-4fc9-8266-cedb736bacaa instance-manager-r-61277092 longhornio/longhorn-engine:v1.1.2 3h54m
pvc-dbcbe588-a088-45b4-9972-74b0e6ca0b58-r-86a35cd3 running k8s-node1 3d40b18a-c0e9-459c-b37e-d878152d1261 instance-manager-r-d8a9eb0e longhornio/longhorn-engine:v1.1.2 3h54m
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