django - 封装 PostgreSQL docker 镜像的 Kubernetes Pod 对象无限循环崩溃

Question

我正在尝试在 Kubernetes Google Cloud 集群上运行我的 Django + PostgreSQL 应用程序。我已成功部署以下文件：

1. Django 应用部署
2. Django 应用服务
3. 用于数据库凭证的 Kubernetes Secret 对象
4. PersistentVolumeClaim

但是在将我的 PostgreSQL 数据库部署到集群时遇到了麻烦。这是我的 .yml 文件的定义：

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: PersistentVolumeClaim
metadata:
  name: postgres-pvc
  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

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

这是我运行kubectl logs postgres-85c56dfb9b-95c74命令时遇到的错误：

initdb: directory "/var/lib/postgresql/data" exists but is not empty
It contains a lost+found directory, perhaps due to it being a mount point.
Using a mount point directly as the data directory is not recommended.
Create a subdirectory under the mount point.
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".

有人可以向我解释这个错误。提前致谢！

*****更新******

当我运行kubectl logs $pod时，我收到以下错误（即使容器在集群上运行）：

Host: 10.52.1.5
Production - Using "POSTGRESQL" Database
/usr/local/lib/python3.6/site-packages/psycopg2/__init__.py:144: UserWarning: The psycopg2 wheel package will be renamed from release 2.8; in order to keep installing from binary please use "pip install psycopg2-binary" instead. For details see: <http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
  """)
Host: 10.52.1.5
Production - Using "POSTGRESQL" Database
/usr/local/lib/python3.6/site-packages/psycopg2/__init__.py:144: UserWarning: The psycopg2 wheel package will be renamed from release 2.8; in order to keep installing from binary please use "pip install psycopg2-binary" instead. For details see: <http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
  """)
Performing system checks...

System check identified no issues (0 silenced).
Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x7f62f4c948c8>
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 216, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 194, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/postgresql/base.py", line 168, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/usr/local/lib/python3.6/site-packages/psycopg2/__init__.py", line 130, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
psycopg2.OperationalError: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/django/utils/autoreload.py", line 225, in wrapper
    fn(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 124, in inner_run
    self.check_migrations()
  File "/usr/local/lib/python3.6/site-packages/django/core/management/base.py", line 427, in check_migrations
    executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/executor.py", line 18, in __init__
    self.loader = MigrationLoader(self.connection)
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/loader.py", line 49, in __init__
    self.build_graph()
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/loader.py", line 206, in build_graph
    self.applied_migrations = recorder.applied_migrations()
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 61, in applied_migrations
    if self.has_table():
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 44, in has_table
    return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 255, in cursor
    return self._cursor()
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 232, in _cursor
    self.ensure_connection()
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 216, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.6/site-packages/django/db/utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 216, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 194, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/postgresql/base.py", line 168, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/usr/local/lib/python3.6/site-packages/psycopg2/__init__.py", line 130, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
django.db.utils.OperationalError: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?

这是来自我的 settings.py 文件：

import socket

print("Host: "+socket.gethostbyname(socket.gethostname()))


if(os.getenv('POSTGRES_DB_HOST')==None):
    print('Development - Using "SQLITE3" Database')
    DATABASES = {
        'default':{
            'ENGINE': 'django.db.backends.sqlite3',
            'NAME': os.path.join(BASE_DIR,'db.sqlite3'),
        }
    }
else:
    print('Production - Using "POSTGRESQL" Database')
    DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'NAME': 'agent_technologies_db',
            'USER': 'stefan_radonjic',
            'PASSWORD': 'cepajecar995',
            'HOST': os.getenv('POSTGRES_HOST'),
            'PORT': os.getenv('POSTGRES_PORT'),
            }
    }

我运行kubectl logs $pod命令时遇到的错误可能是因为 PostgreSQL contianer 没有运行所以它找不到它还是？如果有人对我项目的其他文件感兴趣，这里是 github 链接：https ://github.com/StefanCepa/agent-technologies-bachelor

标签： djangopostgresqldockerkubernetes

Answer 1

对我来说，它看起来不像一个错误，更像是一个警告。PostgreSQL 抱怨你应该为 Postgres 数据文件夹使用一个完全空的目录。应用程序告诉您要做的是在您的卷中创建一个空目录并挂载该特定子目录。这将通过执行以下操作来完成：

• 在你的卷中创建一个子目录，你可以使用例如一个 initContainer 来挂载卷并创建目录。

• 既然你有一个创建目录的卷，那么你可以修改 Postgres 中的 postgres-volume-mount 并将 subPath 添加到新创建的目录中。

      - name: postgres-volume-mount
        mountPath: /var/lib/postgresql/data
        subPath: NAME_OF_YOUR_SUBDIRECTORY