Kubernetes - 封装 DB 的 Pod 崩溃

Question

我在尝试将 Django 应用程序部署到 Kubernetes 集群时遇到问题。更具体地说，当我尝试部署 PostgreSQL 时。

这是我的 .YML 部署文件的样子：

apiVersion: v1
kind: Service
metadata:
  name: postgres-service
spec:
  selector:
    app: postgres-container
    tier: backend
  ports:
    - protocol: TCP
      port: 5432
      targetPort: 5432
  type: ClusterIP
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: postgres-pv
  labels:
      type: local
spec:
  accessModes:
    - ReadWriteOnce
  capacity:
    storage: 2Gi
  hostPath:
    path: /tmp/data/persistent-volume-1 #U okviru cvora n
  persistentVolumeReclaimPolicy: Retain
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres-pv-claim
  labels:
    type: local
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi
---
apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: postgres
spec:
  replicas: 1
  selector:
    matchLabels:
      app: postgres-container
      tier: backend
  template:
    metadata:
      labels:
        app: postgres-container
        tier: backend
    spec:
      containers:
        - name: postgres-container
          image: postgres:9.6.6
          env:
            - name: POSTGRES_USER
              valueFrom:
                secretKeyRef:
                  name: postgres-credentials
                  key: user

            - name: POSTGRES_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: postgres-credentials
                  key: password

            - name: POSTGRES_DB
              value: agent_technologies_db
          ports:
            - containerPort: 5432
          volumeMounts:
            - name: postgres-volume-mount
              mountPath: /var/lib/postgresql/data/db-files

      volumes:
        - name: postgres-volume-mount
          persistentVolumeClaim:
            claimName: postgres-pv-claim
        - name: postgres-credentials
          secret:
            secretName: postgres-credentials

这是我运行 kubectl get pods 命令时得到的结果：

NAME                                             READY     STATUS             RESTARTS   AGE
agent-technologies-deployment-7c7c6676ff-8p49r   1/1       Running            0          2m
agent-technologies-deployment-7c7c6676ff-dht5h   1/1       Running            0          2m
agent-technologies-deployment-7c7c6676ff-gn8lp   1/1       Running            0          2m
agent-technologies-deployment-7c7c6676ff-n9qql   1/1       Running            0          2m
postgres-8676b745bf-8f7jv                        0/1       CrashLoopBackOff   4          3m

当我尝试使用 kubectl logs $pod_name 检查 PostgreSQL 部署的情况时，我得到了以下结果：

initdb: directory "/var/lib/postgresql/data" exists but is not empty
If you want to create a new database system, either remove or empty
the directory "/var/lib/postgresql/data" or run initdb
with an argument other than "/var/lib/postgresql/data".
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.utf8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

注意：我使用 Google Cloud 作为提供商。

Answer 1

您不能在/var/lib/postgres/data/whatever 中拥有您的数据库。

通过/var/lib/postgres/whatever 更改该路径，它将起作用。

17.2.1。使用辅助文件系统

许多安装在计算机的“根”卷之外的文件系统（卷）上创建它们的数据库集群。如果您选择这样做，建议不要尝试使用辅助卷的最顶层目录（安装点）作为数据目录。最佳实践是在 PostgreSQL 用户拥有的挂载点目录中创建一个目录，然后在其中创建数据目录。这样可以避免权限问题，尤其是对于 pg_upgrade 等操作，并且还可以确保在辅助卷脱机时彻底失败。

顺便说一句，我必须创建一个秘密，因为它不在帖子中：

apiVersion: v1
kind: Secret
metadata:
  name: postgres-credentials
type: Opaque
data:
  user: cG9zdGdyZXM=            #postgres
  password: cGFzc3dvcmQ=        #password

请注意，用户名必须是“postgres”。我不知道你是否在报道这个......