Run docker in docker on a dedicated server? - docker

Question

I will run docker on a dedicated sever by a service provider. It is not
possible to install docker on this server. Apache, Git and a lot more is
installed. So I try to run docker in a container. I will pull a docker image
from the gitlab registry and run in a sub domain. I wrote a .gitlab-ci.yml. But
I get an error message.
I found this answer:
You can't (*) run Docker inside Docker containers or images. You can't (*)
start background services inside a Dockerfile. As you say, commands like
systemctl and service don't (*) work inside Docker anywhere. And in any case
you can't use any host-system resources, including the host's Docker socket,
from anywhere in a Dockerfile.
How do I solve this problem?
$ sudo docker run hello-world
docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.
See 'docker run --help'.
ERROR: Job failed: exit code 1
.gitlab-ci.yml
image: ubuntu:latest
before_script:
- apt-get update
- apt-get install -y apt-transport-https ca-certificates curl software-properties-common
- curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add
- apt-key fingerprint 0EBFCD88
- add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
stages:
- test
test:
stage: test
script:
- apt-get update
- apt-cache search docker-ce
- apt-get install -y docker-ce
- docker run -d hello-world

Answer 1

This .gitlab-ci.yml works for me.
image: ubuntu:latest
services:
- docker:dind
variables:
DOCKER_DRIVER: overlay2
DOCKER_HOST: tcp://docker:2375/
before_script:
- apt-get update
- apt-get install -y apt-transport-https ca-certificates curl software-properties-common
- curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add
- apt-key fingerprint 0EBFCD88
- add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
- apt-get update
stages:
- test
test:
stage: test
script:
- apt-get install -y docker-ce
- docker info
- docker pull ...
- docker run -p 8000:8000 -d --name ...

Answer 2

The answer that you found.... is a little old. There are options to run systemd in a container and it is also possible to run some systemctl-replacement script.
However, I am not sure what application you really want to install.