Add runner that can run docker inside a container

docker-compose.yml

@@ -143,10 +143,10 @@ services:
     restart: always
 
   # ---------------------------------------------------------------------------
-  # Gitlab runner for CI.
+  # Gitlab runners for CI.
   # ---------------------------------------------------------------------------
 
-  runner:
+  runner-main:
     container_name: runner-main
     build: runner
     image: gitlab.wojciechkozlowski.eu:8443/wojtek/loki/runner
@@ -155,3 +155,17 @@ services:
       - runner_main_home:/home/gitlab-runner
       - /var/run/docker.sock:/var/run/docker.sock
     restart: always
+
+  docker-dind:
+    container_name: docker-dind
+    image: docker:dind
+    privileged: true
+    restart: always
+
+  runner-docker:
+    container_name: runner-docker
+    build: runner
+    image: gitlab.wojciechkozlowski.eu:8443/wojtek/loki/runner
+    links:
+      - docker-dind:docker
+    restart: always

runner/Dockerfile

@@ -9,14 +9,36 @@ ENV DEBIAN_FRONTEND noninteractive
 RUN apt update && apt upgrade -y
 
 # Install gitlab-runner
-RUN apt install -y gnupg && bash /tmp/script.deb.sh
+RUN apt install -y gnupg2 && bash /tmp/script.deb.sh
 RUN apt install -y gitlab-runner
 
 # Install pre-requisites for running tests
-RUN apt install -y build-essential \
-                   python \
+
+# Common
+RUN apt install -y build-essential
+
+# Python
+RUN apt install -y python \
                    python-pip
 
+# Docker
+RUN apt install -y apt-transport-https \
+                   ca-certificates \
+                   curl \
+                   gnupg2 \
+                   software-properties-common
+
+RUN curl -fsSL https://download.docker.com/linux/$(. /etc/os-release; echo "$ID")/gpg | apt-key add -
+
+RUN add-apt-repository \
+    "deb [arch=amd64] https://download.docker.com/linux/$(. /etc/os-release; echo "$ID") \
+    $(lsb_release -cs) \
+    stable"
+
+RUN apt update && apt install -y docker-ce
+
+ENV DOCKER_HOST "tcp://docker:2375"
+
 # Preserve runner's data
 VOLUME ["/etc/gitlab-runner", "/home/gitlab-runner"]