What is the difference between Docker Unix socket on ubuntu vs alpine?-CodePudding

I am running through a problem where I can't mount Unix docker socket to an alpine container but works with ubuntu container.

docker-compose using alpine image

version: '3.8'

services:
  cluster:
    image:  alpine  
    tty: true  
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
      - "/usr/bin/docker:/usr/bin/docker"

running docker command in the alpine container:

/ # docker --version
sh: docker: not found

docker-compose using ubuntu image

version: '3.8'

services:
  cluster:
    image:  ubuntu:20.04
    tty: true  
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
      - "/usr/bin/docker:/usr/bin/docker"

running docker command in the ubuntu container:

root@5f30b4143c43:/# docker --version
Docker version 20.10.12, build e91ed57

I don't get why I can access my host docker env using the ubuntu container but not with the alpine one? is there anything missing in the configuration?

CodePudding user response：

Your error has nothing to do with the socket:

/ # docker --version
sh: docker: not found

You're seeing this because you're trying to run a binary compiled for glibc platform, while Alpine is built using MUSL libc.

You would need to install a version of the docker client built specifically for use under Alpine (or just pick almost any other image).