选择用 postgress 作为实例，因为它需要一个持久化存储来运行

1.创建 local storage class

新建 local-storage.yaml 文件，内容如下：

yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: local-storage
provisioner: kubernetes.io/no-provisioner
volumeBindingMode: WaitForFirstConsumer

2.在某一个 worker node 上创建一个文件夹

shell
$ ssh [email protected]

shell
$ [email protected]: mkdir -p /data/volumes/postgres
$ [email protected]: chmod 777 /data/volumes/postgres

3.创建一个 PersistentVolume 关联刚才的 worker node 和对应的文件夹

yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: postgres-local-pv
spec:
  capacity:
    storage: 8Gi
  accessModes:
  - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: local-storage
  local:
    path: /data/volumes/postgres
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values:
          - kube-worker-1

4.创建一个 PersistentVolumeClaim 关联刚才的 PersistentVolume

yaml
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: postgres-pvc
spec:
  accessModes:
  - ReadWriteOnce
  storageClassName: local-storage
  resources:
    requests:
      storage: 8Gi

以上 4 个步骤执行完毕之后，需要查看 postgres-local-pv 是否处于 Available 状态

shell
$ kubectl get persistentvolumes
NAME                CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS    REASON   AGE
postgres-local-pv   8Gi        RWO            Retain           Available           local-storage            4m3s

另外 postgres-pvc 应该是处于 pending 状态，因为它并没有被任意一个 pod 去使用

shell
$ kubectl get persistentvolumeclaims
NAME           STATUS    VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS    AGE
postgres-pvc   Pending                                      local-storage   5m44s

接下来，我们需要启动一个 postgres 实例，让他去使用我们刚才创建的 postgres-pvc

使用 helm 拉取 postgress 到本地

shell
$ helm repo add bitnami https://charts.bitnami.com/bitnami
$ helm pull bitnami/postgresql --untar

修改配置文件

修改 values.yaml 里面的关键内容：

yaml
primary:
  service:
    type: LoadBalancer
  persistence:
    existingClaim: "postgres-pvc"
    storageClass: "local-storage"

安装 postgres

执行安装

shell
$ helm install postgres ./postgresql

接下来你会看到如下输出

shell
NAME: postgres
LAST DEPLOYED: Thu Nov 17 05:49:43 2022
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
CHART NAME: postgresql
CHART VERSION: 12.1.2
APP VERSION: 15.1.0

** Please be patient while the chart is being deployed **

PostgreSQL can be accessed via port 5432 on the following DNS names from within your cluster:

    postgres-postgresql.default.svc.cluster.local - Read/Write connection

To get the password for "postgres" run:

    export POSTGRES_PASSWORD=$(kubectl get secret --namespace default postgres-postgresql -o jsonpath="{.data.postgres-password}" | base64 -d)

To connect to your database run the following command:

    kubectl run postgres-postgresql-client --rm --tty -i --restart='Never' --namespace default --image docker.io/bitnami/postgresql:15.1.0-debian-11-r0 --env="PGPASSWORD=$POSTGRES_PASSWORD" \
      --command -- psql --host postgres-postgresql -U postgres -d postgres -p 5432

    > NOTE: If you access the container using bash, make sure that you execute "/opt/bitnami/scripts/postgresql/entrypoint.sh /bin/bash" in order to avoid the error "psql: local user with ID 1001} does not exist"

To connect to your database from outside the cluster execute the following commands:

  NOTE: It may take a few minutes for the LoadBalancer IP to be available.
        Watch the status with: 'kubectl get svc --namespace default -w postgres-postgresql'

    export SERVICE_IP=$(kubectl get svc --namespace default postgres-postgresql --template "{{ range (index .status.loadBalancer.ingress 0) }}{{ . }}{{ end }}")
    PGPASSWORD="$POSTGRES_PASSWORD" psql --host $SERVICE_IP --port 5432 -U postgres -d postgres

校验 postgres 成功运行

查看 pod 是否成功启动：

shell
$ kubectl get pod postgres-postgresql-0 
NAME                    READY   STATUS    RESTARTS   AGE
postgres-postgresql-0   1/1     Running   0          2m52s

重新查看

shell
$ kubectl get persistentvolumeclaims
NAME           STATUS   VOLUME              CAPACITY   ACCESS MODES   STORAGECLASS    AGE
postgres-pvc   Bound    postgres-local-pv   8Gi        RWO            local-storage   12m

此时它已经处于 Bound 状态，就说明它已经成功挂在到 pod 上了。

使用客户端链接到数据库

首先下载并且安装 DBeaver -> https://dbeaver.io/

然后执行如下命令获取 LoadBalancer 给 postgres 分配的 IP

shell
$ kubectl get svc postgres-postgresql
NAME                  TYPE           CLUSTER-IP       EXTERNAL-IP       PORT(S)          AGE
postgres-postgresql   LoadBalancer   10.100.241.128   192.168.137.121   5432:30356/TCP   34m

通过命令行获取安装 postgres 时系统随机生成的链接字符串密码

shell
$ kubectl get secret --namespace default postgres-postgresql -o jsonpath="{.data.postgres-password}" | base64 -d
$ 2rPcHK0DOE

配置链接

完成。