add subPath to volumeMount postgres-data

[xring]

Summary

• What changed?

add subPath to postgres-data volumeMount

• Why is this needed?

Full Deployment (with PostgreSQL + Redis) may fail because of lost+found:

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.

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

Validation

• Backend tests passed
• Frontend typecheck/build passed
• OpenAPI SDK regenerated or checked when API contracts changed
• Smoke test run when relevant

Commands run:

kubectl apply -k deploy/k8s/overlays/with-infra/

Risk

• User-facing impact:
• Deployment or migration impact:
• Rollback approach:

Notes

• Related issue:
• Follow-up work:
• Docs or operator runbooks updated when behavior changed:

[CLAassistant]

All committers have signed the CLA.

[XiaoSeS]

Review: subPath 对已有部署的兼容性

代码本身 LGTM，subPath: pgdata 是解决 lost+found 问题的标准做法。

潜在风险

对于已有数据的部署，加上 subPath 后 PG 会看到一个空的 pgdata/ 子目录，触发重新 initdb，老数据（在 PV 根目录）从容器视角"消失"。

建议：添加 init container 自动迁移

可以加一个 init container，在 PG 启动前检测并自动迁移数据：

initContainers:
  - name: migrate-pgdata
    image: busybox:1.36
    command:
      - sh
      - -c
      - |
        # If PG_VERSION exists at root but not in subPath, migrate
        if [ -f /data/PG_VERSION ] && [ ! -f /data/pgdata/PG_VERSION ]; then
          echo "Migrating existing data to pgdata/ subdirectory..."
          mkdir -p /data/pgdata
          # Move everything except pgdata/ and lost+found/
          for item in /data/*; do
            base=$(basename "$item")
            if [ "$base" != "pgdata" ] && [ "$base" != "lost+found" ]; then
              mv "$item" /data/pgdata/
            fi
          done
          echo "Migration complete."
        else
          echo "No migration needed."
        fi
    volumeMounts:
      - name: postgres-data
        mountPath: /data

这样：

• 全新部署：/data 为空（或只有 lost+found），init container 跳过，PG 正常 initdb 到 /data/pgdata/
• 已有部署升级：init container 检测到 PG_VERSION 在根目录，自动把数据移到 pgdata/ 子目录，PG 启动后无缝衔接

如果觉得 init container 过重，也可以在 PR 描述的 Risk 栏里注明"仅适用于全新部署，已有部署需手动迁移数据"即可。