Can't set volume value right when running owncloud docker container - docker

Question

I followed this guide to install owncloud server on my VPS, it works. However there is an issue when I was trying to mount the file volume to host server. Below is the docker-compose.yml file I use. If I run the docker image with the yml file directly, I can't find there is any owncloud data under the directory /mnt/data of my VPS even I created /mnt/data manually.
version: '2.1'
volumes:
files:
driver: local
mysql:
driver: local
backup:
driver: local
redis:
driver: local
services:
owncloud:
image: owncloud/server:${OWNCLOUD_VERSION}
restart: always
ports:
- ${HTTPS_PORT}:443
- ${HTTP_PORT}:80
depends_on:
- db
- redis
environment:
- OWNCLOUD_DOMAIN=${OWNCLOUD_DOMAIN}
- OWNCLOUD_DB_TYPE=mysql
- OWNCLOUD_DB_NAME=owncloud
- OWNCLOUD_DB_USERNAME=owncloud
- OWNCLOUD_DB_PASSWORD=owncloud
- OWNCLOUD_DB_HOST=db
- OWNCLOUD_ADMIN_USERNAME=${ADMIN_USERNAME}
- OWNCLOUD_ADMIN_PASSWORD=${ADMIN_PASSWORD}
- OWNCLOUD_UTF8MB4_ENABLED=true
- OWNCLOUD_REDIS_ENABLED=true
- OWNCLOUD_REDIS_HOST=redis
healthcheck:
test: ["CMD", "/usr/bin/healthcheck"]
interval: 30s
timeout: 10s
retries: 5
volumes:
- files:/mnt/data
db:
image: webhippie/mariadb:latest
restart: always
environment:
- MARIADB_ROOT_PASSWORD=owncloud
- MARIADB_USERNAME=owncloud
- MARIADB_PASSWORD=owncloud
- MARIADB_DATABASE=owncloud
- MARIADB_MAX_ALLOWED_PACKET=128M
- MARIADB_INNODB_LOG_FILE_SIZE=64M
- MARIADB_INNODB_LARGE_PREFIX=ON
- MARIADB_INNODB_FILE_FORMAT=Barracuda
healthcheck:
test: ["CMD", "/usr/bin/healthcheck"]
interval: 30s
timeout: 10s
retries: 5
volumes:
- mysql:/var/lib/mysql
- backup:/var/lib/backup
redis:
image: webhippie/redis:latest
restart: always
environment:
- REDIS_DATABASES=1
healthcheck:
test: ["CMD", "/usr/bin/healthcheck"]
interval: 30s
timeout: 10s
retries: 5
volumes:
- redis:/var/lib/redis
So I tried modifying line files:/mnt/data to files:/mnt/data:/mnt/data, then it prompted me with following error.
ERROR: for ownclouddockerserver_owncloud_1 Cannot create container for service owncloud: invalid bind mount spec "ownclouddockerserver_files:/mnt/data:/mnt/data": invalid mode: /mnt/data
ERROR: for owncloud Cannot create container for service owncloud: invalid bind mount spec "ownclouddockerserver_files:/mnt/data:/mnt/data": invalid mode: /mnt/data
Can anyone help me out to figure out the right way of mounting external directory to container's? Much appreciated.

Answer 1

The /mnt/data directory exists only inside your docker container.
It is mapped to a generated (virtual) drive called files.
In order to map the /mnt/data directory to a local directory, you use:
/my/local/directory:/mnt/data