k8s使用localpath为pod动态提供存储

在k8s环境中，我们经常会使用本机路径作为持久化存储。在k8s官方文档中有两种方式使用本机存储，一种是hostPath，另一种是local volume，这两种都不支持动态扩容，并且程序移植改动比较大，而local-path-provisioner很好的弥补了这一缺陷。

使用local-path-provisioner的步骤：
一、创建local-path路径

[root@node1 ~]# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sr0          11:0    1  470K  0 rom  
vda         253:0    0  100G  0 disk 
└─vda1      253:1    0  100G  0 part /
vdb         253:16   0  500G  0 disk 
└─nfs-lvol0 252:0    0  495G  0 lvm  /data
vdc         253:32   0  400G  0 disk        ###添加一块磁盘
[root@node1 ~]# mkdir /local     ####创建目录


[root@node1 ~]# pvcreate /dev/vdc    ####创建pv
WARNING: xfs signature detected on /dev/vdc at offset 0. Wipe it? [y/n]: y
  Wiping xfs signature on /dev/vdc.
  Physical volume "/dev/vdc" successfully created.

[root@node1 ~]# vgcreate local-path /dev/vdc    ####创建vg
  Volume group "local-path" successfully created
[root@node1 ~]# 
[root@node1 ~]# vgs
  VG         #PV #LV #SN Attr   VSize    VFree   
  local-path   1   0   0 wz--n- <400.00g <400.00g
  nfs          1   1   0 wz--n- <500.00g   <5.00g
[root@node1 ~]# 
[root@node1 ~]# lvcreate --size 300G local-path    ####创建lvm
  Logical volume "lvol0" created.
[root@node1 ~]# 
[root@node1 ~]# mkfs.xfs /dev/local-path/lvol0 
meta-data=/dev/local-path/lvol0  isize=512    agcount=4, agsize=19660800 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=78643200, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=38400, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
[root@node1 ~]# 

[root@node1 ~]# mount /dev/local-path/lvol0 /local/     ####挂载lvm到local
[root@node1 ~]# 
[root@node1 ~]# cat /etc/fstab 
LABEL=img-rootfs / xfs defaults 0 1
/dev/nfs/lvol0 /data xfs defaults 0 1
/dev/local-path/lvol0 /local xfs defaults 0 1     ####写入fstab，开机可以自动挂载
[root@node1 ~]#

二、启动local-path-provisioner

1:编辑local-path-storage.yaml文件如下：
---
apiVersion: v1
kind: Namespace
metadata:
  name: local-path-storage

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: local-path-provisioner-service-account
  namespace: local-path-storage

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: local-path-provisioner-role
rules:
  - apiGroups: [ "" ]
    resources: [ "nodes", "persistentvolumeclaims", "configmaps" ]
    verbs: [ "get", "list", "watch" ]
  - apiGroups: [ "" ]
    resources: [ "endpoints", "persistentvolumes", "pods" ]
    verbs: [ "*" ]
  - apiGroups: [ "" ]
    resources: [ "events" ]
    verbs: [ "create", "patch" ]
  - apiGroups: [ "storage.k8s.io" ]
    resources: [ "storageclasses" ]
    verbs: [ "get", "list", "watch" ]

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: local-path-provisioner-bind
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: local-path-provisioner-role
subjects:
  - kind: ServiceAccount
    name: local-path-provisioner-service-account
    namespace: local-path-storage

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: local-path-provisioner
  namespace: local-path-storage
spec:
  replicas: 1
  selector:
    matchLabels:
      app: local-path-provisioner
  template:
    metadata:
      labels:
        app: local-path-provisioner
    spec:
      serviceAccountName: local-path-provisioner-service-account
      containers:
        - name: local-path-provisioner
          image: docker.io/rancher/local-path-provisioner:v0.0.22
          imagePullPolicy: IfNotPresent
          command:
            - local-path-provisioner
            - --debug
            - start
            - --config
            - /etc/config/config.json
          volumeMounts:
            - name: config-volume
              mountPath: /etc/config/
          env:
            - name: PROVISIONER_NAME
              value: rancher.io/local-path
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
      volumes:
        - name: config-volume
          configMap:
            name: local-path-config

---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: local-path
provisioner: rancher.io/local-path
volumeBindingMode: WaitForFirstConsumer
reclaimPolicy: Delete

---
kind: ConfigMap
apiVersion: v1
metadata:
  name: local-path-config
  namespace: local-path-storage
data:
  config.json: |-
    {
            "nodePathMap":[
            {
                    "node":"DEFAULT_PATH_FOR_NON_LISTED_NODES",
                    "paths":["/local"]             #####替换实际路径
            }
            ]
    }
  setup: |-
    #!/bin/sh
    set -eu
    mkdir -m 0777 -p "$VOL_DIR"
  teardown: |-
    #!/bin/sh
    set -eu
    rm -rf "$VOL_DIR"
  helperPod.yaml: |-
    apiVersion: v1
    kind: Pod
    metadata:
      name: helper-pod
    spec:
      containers:
      - name: helper-pod
        image: busybox
        imagePullPolicy: IfNotPresent
[root@node1 local]# 
[root@node1 local]#   kubectl apply -f local-path-storage.yaml

####查看pod是否正常启动
[root@node1 ~]# kubectl get po  -n local-path-storage
NAME                                     READY   STATUS    RESTARTS   AGE
local-path-provisioner-c755757b6-5gcr6   1/1     Running   0          23d
[root@node1 ~]# 

####查看日志，已经能够识别到local 路径
[root@node1 ~]# kubectl logs local-path-provisioner-c755757b6-5gcr6 -n local-path-storage
time="2023-04-28T07:28:26Z" level=debug msg="Applied config: {\"nodePathMap\":[{\"node\":\"DEFAULT_PATH_FOR_NON_LISTED_NODES\",\"paths\":[\"/local\"]}]}" 
time="2023-04-28T07:28:26Z" level=debug msg="Provisioner started" 
I0428 07:28:26.478078       1 controller.go:773] Starting provisioner controller rancher.io/local-path_local-path-provisioner-c755757b6-5gcr6_d00cd9cb-89e8-4911-b9c3-f7ed5a89a368!
I0428 07:28:26.578610       1 controller.go:822] Started provisioner controller rancher.io/local-path_local-path-provisioner-c755757b6-5gcr6_d00cd9cb-89e8-4911-b9c3-f7ed5a89a368


2：创建storageclass，如下：
---
apiVersion: storage.k8s.io/v1          
kind: StorageClass                     
metadata:                              
  name: local-path                     
provisioner: rancher.io/local-path    ####上述定义的provisioner 名称
volumeBindingMode: WaitForFirstConsumer
reclaimPolicy: Delete

执行sc.yaml如下：
[root@node1 local]# kubectl apply -f sc.yaml 
[root@node1 ~]# kubectl get sc
NAME         PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
local-path   rancher.io/local-path   Delete          WaitForFirstConsumer   false                  23d
[root@node1 ~]# 

3：local-path的使用
在yaml文件中，直接使用sc name，动态创建pvc即可，local-path适用于单机环境，如果是多个node,要确保每个节点都有local-path才能保证pod正常调度成功