Add Dockerfile for CI image

.gitlab-ci.yml

+ci_test_image:
+  stage: build
+  variables:
+    DOCKER_DRIVER: overlay2
+  image: docker:stable
+  services:
+    - docker:dind
+  before_script:
+    - docker info
+  script:
+    - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
+    - docker build -t openappstack/bootstrap/bootstrap-ci test/
+    - docker tag openappstack/bootstrap/bootstrap-ci docker.greenhost.net/openappstack/bootstrap/bootstrap-ci
+    - docker push docker.greenhost.net/openappstack/bootstrap/bootstrap-ci
+  only:
+    changes:
+      - test/Dockerfile
+
 control_image:
   stage: build
   variables:
@@ -18,16 +36,12 @@ control_image:
 
 bootstrap:
   stage: deploy
-  image: alpine
+  image: docker.greenhost.net/openappstack/bootstrap/bootstrap-ci
   script:
     # Ensure test/ is not world-writable otherwise ansible-playbook refuses to run, see
     # https://docs.ansible.com/ansible/devel/reference_appendices/config.html#cfg-in-world-writable-dir
     - chmod 755 test/
     - cd test/
-    - apk --no-cache add ansible musl-dev linux-headers gcc py3-psutil py3-requests openssh-client chromium chromium-chromedriver
-    # p3-tabulate is not installable, see https://code.greenhost.net/openappstack/bootstrap/issues/54
-    # There is no alpine package for testinfra and behave(-webdriver)
-    - pip3 install behave-webdriver tabulate testinfra
     - eval $(ssh-agent -s)
     - echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add - > /dev/null
     - ANSIBLE_HOST_KEY_CHECKING=False python3 -u ./ci-bootstrap.py --create_droplet

test/Dockerfile

+FROM alpine
+
+LABEL Name="Openappstack bootstrap CI test image"
+LABEL version="0.0.2"
+LABEL vendor1="Greenhost"
+
+RUN apk --no-cache add \
+  ansible \
+  musl-dev \
+  linux-headers \
+  gcc \
+  py3-psutil \
+  py3-requests \
+  openssh-client \
+  chromium \
+  chromium-chromedriver
+
+# p3-tabulate is not installable via pip3,
+# see https://code.greenhost.net/openappstack/bootstrap/issues/54
+# There is no alpine package for testinfra and behave(-webdriver)
+RUN pip3 install behave-webdriver tabulate testinfra