postgresql - 如何使用 NFS 卷在 Kubernetes 上部署 Postgresql

Question

我正在使用以下 list 在 NFS 持久卷内的 kubernetes 上部署 postgresql:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs2
spec:
  capacity:
    storage: 6Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  nfs:
    server: 10.139.82.123
    path:  /nfsfileshare/postgres
---

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: nfs2
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 6Gi
---
apiVersion: v1
kind: Service
metadata:
  name: db

  labels:
    app: aiflow-db
spec:
  selector:
    app: aiflow-db
  clusterIP: None
  ports:
  - port: 5432
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: db
  namespace: test-aiflow
  labels:
    app: aiflow-db
spec:
  selector:
    matchLabels:
      app: aiflow-db
  template:
    metadata:
      labels:
        app: aiflow-db
    spec:
      containers:
      - name: db
        image: postgresql:10
        ports:
        - containerPort: 5432
        env:
        - name: PGDATA
          value: /var/lib/postgresql/data/pgdata
        volumeMounts:
        - mountPath: /var/lib/postgresql/data/pgdata
          name: nfs2
      volumes:
        - name: nfs2
          persistentVolumeClaim:
            claimName: nfs2
      restartPolicy: Always

pg数据可以挂载到nfs服务器(/nfsfileshare/postgres *(rw,async,no_subtree_check,no_root_squash)):

total 124
drwx------ 19  999 root    4096 Aug  7 11:10 ./
drwxrwxrwx  5 root root    4096 Aug  7 10:28 ../
drwx------  3  999 docker  4096 Aug  7 11:02 base/
drwx------  2  999 docker  4096 Aug  7 11:10 global/
drwx------  2  999 docker  4096 Aug  7 11:01 pg_commit_ts/
drwx------  2  999 docker  4096 Aug  7 11:01 pg_dynshmem/
-rw-------  1  999 docker  4513 Aug  7 11:02 pg_hba.conf
-rw-------  1  999 docker  1636 Aug  7 11:02 pg_ident.conf
drwx------  4  999 docker  4096 Aug  7 11:09 pg_logical/
drwx------  4  999 docker  4096 Aug  7 11:01 pg_multixact/
drwx------  2  999 docker  4096 Aug  7 11:10 pg_notify/
drwx------  2  999 docker  4096 Aug  7 11:02 pg_replslot/
drwx------  2  999 docker  4096 Aug  7 11:01 pg_serial/
drwx------  2  999 docker  4096 Aug  7 11:01 pg_snapshots/
drwx------  2  999 docker  4096 Aug  7 11:02 pg_stat/
drwx------  2  999 docker  4096 Aug  7 11:02 pg_stat_tmp/
drwx------  2  999 docker  4096 Aug  7 11:02 pg_subtrans/
drwx------  2  999 docker  4096 Aug  7 11:02 pg_tblspc/
drwx------  2  999 docker  4096 Aug  7 11:01 pg_twophase/
-rw-------  1  999 docker     3 Aug  7 11:02 PG_VERSION
drwx------  3  999 docker  4096 Aug  7 11:02 pg_wal/
drwx------  2  999 docker  4096 Aug  7 11:02 pg_xact/
-rw-------  1  999 docker    88 Aug  7 11:02 postgresql.auto.conf
-rw-------  1  999 docker 22729 Aug  7 11:02 postgresql.conf
-rw-------  1  999 docker    74 Aug  7 11:10 postmaster.pid

但是容器卡在下面的日志中:

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.

fixing permissions on existing directory /var/lib/postgresql/data/pgdata ... ok creating subdirectories ... ok selecting default max_connections ... 100 selecting default shared_buffers ... 128MB selecting dynamic shared memory implementation ... posix creating configuration files ... ok running bootstrap script ... ok

它似乎卡在了引导后初始化。

它仅在我不使用 nfs 卷(通过使用 hostPath 卷工作)时有效，这是为什么？

Answer 1

NFS 不支持 fsync 内核 vfs 调用，这是确保在磁盘上写出重做日志所需的事务日志。所以当你需要使用RDBMS时，你应该使用 block 存储，比如PostgreSQL和MySQL。尽管您可以在 NFS 上运行，但您可能会失去数据一致性。