Postgres Docker容器数据无法挂载到本地

Question

I'm trying to do data persistence in postgres. But when I want to mount the data folder into my local file, I get this error.

fixing permissions on existing directory /var/lib/postgresql/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
LOG:  could not link file "pg_xlog/xlogtemp.25" to "pg_xlog/000000010000000000000001": Operation not permitted
FATAL:  could not open file "pg_xlog/000000010000000000000001": No such file or directory
child process exited with exit code 1
initdb: removing contents of data directory "/var/lib/postgresql/data"
running bootstrap script ...

Here's my YAML file

version: '3.1'

services:

  postgres:
    restart: always
    image: postgres:9.6.4-alpine
    ports:
      - 8100:5432
    volumes:
      - ./pgdata:/var/lib/postgresql/data
    environment:
      POSTGRES_PASSWORD: root

I'm using docker toolbox on windows. The docker machine in Virtual Box.

Answer 1

Looks like it has to be /mnt/sda1/var/lib/docker/volumes/psql/_data for windows docker toolbox. This worked for me

docker run -it --name psql -p 5432:5432 -v psql:/var/lib/postgresql/data postgres:9.5-alpine

"Mounts": [
            {
                "Type": "volume",
                "Name": "psql",
                "Source": "/mnt/sda1/var/lib/docker/volumes/psql/_data",
                "Destination": "/var/lib/postgresql/data",
                "Driver": "local",
                "Mode": "z",
                "RW": true,
                "Propagation": ""
            }

docker volume ls

DRIVER              VOLUME NAME
local               65f253d220ad390337daaacf39e4d17000c36616acfe1707e41e92ab26a6a23a
local               761f7eceaed5525b70d75208a1708437e0ddfa3de3e39a6a3c069b0011688a07
local               8a42268e965e6360b230d16477ae78035478f75dc7cb3e789f99b15a066d6812
local               a37e0cf69201665b14813218c6d0441797b50001b70ee51b77cdd7e5ef373d6a
local               psql

Please refer this for more info: bad mount

Answer 2

It looks like you use a shared data directory (host dir shared into the virtual) for database storage.

Only two options make sense:

1) you have a trivial issue with directory permissions

2) you hit a known problem (google!) with some VirtualBox and also VmWare versions that on some Windows versions, you cannot create symlinks in directories shared from the host to virtual machine.

for (2), a workaround is to NOT use shared folder to keep data.

Either way, it's a problem which should be solved by the provider of the docker image itself, or by the provider of virtualizer (vbox, vmware etc).

This is NOT a fault of Windows OS, or PostgreSQL.