Receiving an error from a docker-compose that the user must own the data directory - postgresql

Question

Every time I try to build my image, I get the following error:
The server must be started by the user that owns the data directory.
The following is my docker file:
version: "3.7"
services:
db:
image: postgres
container_name: xxxxxxxxxxxx
volumes:
- ./postgres-data:/var/lib/postgresql/data
environment:
POSTGRES_DB: $POSTGRES_DB
POSTGRES_USER: $POSTGRES_USER
POSTGRES_PASSWORD: $POSTGRES_PASSWORD
nginx:
image: nginx:latest
restart: always
container_name: xxxxxxxxxxxx-nginx
volumes:
- ./deployment/nginx:/etc/nginx
logging:
driver: none
depends_on: ["radio"]
ports:
- 8080:80
- 8081:443
radio:
build:
context: .
dockerfile: "./deployment/Dockerfile"
image: test-radio
command: './manage.py runserver 0:3000'
container_name: xxxxxxxxxxxxxxx
restart: always
depends_on: ["db"]
volumes:
- type: bind
source: ./api
target: /app/api
- type: bind
source: ./xxxxxx
target: /app/xxxxx
environment:
POSTGRES_DB: $POSTGRES_DB
POSTGRES_USER: $POSTGRES_USER
POSTGRES_PASSWORD: $POSTGRES_PASSWORD
POSTGRES_HOST: $POSTGRES_HOST
AWS_KEY_ID: $AWS_KEY_ID
AWS_ACCESS_KEY: $AWS_ACCESS_KEY
AWS_S3_BUCKET_NAME: $AWS_S3_BUCKET_NAME
networks:
default:
The image is built with the following run.sh file:
#!/usr/bin/env sh
if [ ! -f .pass ]; then
openssl rand -base64 32 > .pass
fi
#export POSTGRES_DB="xxxxxxxxxxxxxxxxx"
#export POSTGRES_USER="xxxxxxxxxxxxxx"
#export POSTGRES_PASSWORD="xxxxxxxxxxxxxxxxxxxx"
#export POSTGRES_HOST="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
export POSTGRES_DB="xxxxxxxxxxxxxxxxxx"
export POSTGRES_USER="xxxxxxxxxxxxxxxxxxxx"
export POSTGRES_PASSWORD="`cat .pass`"
export POSTGRES_HOST="db"
export AWS_KEY_ID="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
export AWS_ACCESS_KEY="xxxxxxxxxxxxxxxxxxxxxxxxx"
export AWS_S3_BUCKET_NAME=""
echo "Your psql password is in .pass do not commit this file."
echo "The app will be available on localhost:8080 shortly"
if [ -z "$1" ]; then
docker-compose up
else
docker-compose up $1
fi
I'm wondering if my error is being caused by attempting to use a bash script to deploy the service on a Windows machine?

Answer 1

Details on the issue
The behavior observed by the OP definetely comes from a UID/GID mismatch, given that the specification
volumes:
- ./postgres-data:/var/lib/postgresql/data
(which can be viewed as a docker-compose equivalent of docker run -v "$PWD/postgres-data:/var/lib/postgresql/data" …) bind-mounts the $PWD/postgres-data folder inside the container, giving access to its files as is (including owner/group metadata).
Also, note that the handling of owner/group metadata between host and containers only relies on the numeric UID and GID, not on the owner and group names.
For more information about UIDs and GIDs in a Docker context, see also that article on Medium.
Workarounds if the bind-mount is necessary
For completeness, several possible solutions to workaround the bind-mount UID-mismatch issue (including the most straightforward one that consists in changing the files' UID :) are described in this answer on StackOverflow:
How to have host and container read/write the same files with Docker?
Other solutions
Following #ParanoidPenguin's comment, you may want to use a named volume, which mainly consists in using:
the docker volume command
and/or the docker run option -v …:….
Remarks:
docker run -v PATH1:PATH2 … triggers a bind-mount of PATH1 (host) to PATH2 (container) if and only if PATH1 is absolute (i.e., starts with a /) (e.g., -v "$PWD:$PWD" is a common idiom)
docker run -v NAME:PATH2 … mounts volume NAME to PATH2 (container) if and only if NAME does not contain any / (i.e., matches regexp [a-zA-Z0-9][a-zA-Z0-9_.-]).
even if we don't run docker volume create foo beforehand by hand, docker run -v foo:/data --rm -it debian will create the named volume foo if need be.
in order to populate the files of a named volume (or respectively, backup them) you can use an ephemeral container of image debian, ubuntu or so, combining at the same time a bind-mount and a volume mount:
Add a file /home/user/bar.txt in a new volume foo
file1=/home/user/bar.txt # initial file
uid=2000 # target User-ID in the volume
gid=2000 # target Group-ID in the volume
docker pull debian
docker run -v "$file1:$file1:ro" -v foo:/data \
-e file1="$file1" -e uid="$uid" -e gid="$gid" \
--rm -it debian bash -exc \
'cp -v -- "$file1" /data/bar.txt && chown -v $uid:$gid /data/bar.txt'
docker volume ls
Backup the foo volume in a tarball
date=$(date +'%Y%m%d_%H%M%S')
back="backup_$date.tar.gz"
destdir=/home/user/backup
mkdir -p "$destdir"
docker run -v foo:/data -v "$destdir:/backup" -e back="$back" \
--rm -it debian bash -exc 'tar cvzf "/backup/$back" /data'