Docker mounting different path with same config on 2 different machines - docker

Question

My docker compose entry for the service is:
api:
restart: always
build: ./project/api
volumes:
- ./:/usr/src/app:ro
- ~/data:/root/data:ro # /root is the ~ in container
I run my containers using
sudo docker-compose down && sudo docker-compose up --build -d
I have 2 different machines, both with admin user. On inspection of the containers created:
sudo docker inspect project_api_1 | grep Mounts -A20
On machine 1, admin user is admin:x:1005:1001:Admin User,,,:/home/admin:/bin/zsh and admin:x:1000:1000:Debian:/home/admin:/bin/zsh on machine 2
Output on machine 1
"Mounts": [
{
"Type": "bind",
"Source": "/home/admin/project",
"Destination": "/usr/src/app",
"Mode": "ro",
"RW": false,
"Propagation": "rprivate"
},
{
"Type": "bind",
"Source": "/home/admin/data",
"Destination": "/root/data",
"Mode": "ro",
"RW": false,
"Propagation": "rprivate"
}
],
Output on machine 2
"Mounts": [
{
"Type": "bind",
"Source": "/home/admin/project",
"Destination": "/usr/src/app",
"Mode": "ro",
"RW": false,
"Propagation": "rprivate"
},
{
"Type": "bind",
"Source": "/root/data",
"Destination": "/root/data",
"Mode": "ro",
"RW": false,
"Propagation": "rprivate"
}
],
On machine 1, /root/data points to /home/admin/data which is the desired behavior, but on machine 2 it points to /root/data. I can fix this by using either relative path ./data (which symlinks to ~/data) or by using absolute path /home/admin/data. My docker version is same on both machines - Docker version 17.06.0-ce, build 02c1d87
I'm curious about why is this different?

Answer 1

On your yaml file, you're using ~/data, where ~ is the shorthand for the home directory of the user you used to run docker. From that, I guess you're running docker on machine 1 as admin, while you're running docker on machine 2 as root.
You should remember that the source directory is a directory on your host machine (not the container), so the user relevant to ~ is the user on your host machine.