diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8c9b2adda3fdea532fadf76cd7afea661c3761ea..a040a4a58b374c268d202e3ef7ade8d97dd1805b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -4,6 +4,7 @@
 #
 # Copyright (C) 2018 Research Group Biomedical Physics,
 # Max-Planck-Institute for Dynamics and Self-Organization Göttingen
+# Copyright (C) 2019 Henrik tom Wörden
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as
@@ -22,63 +23,58 @@
 #
 
 variables:
-   CI_REGISTRY_IMAGE: $CI_REGISTRY/caosdb-server-testenv:latest
-   # When using dind service we need to instruct docker, to talk with the
-   # daemon started inside of the service. The daemon is available with
-   # a network connection instead of the default /var/run/docker.sock socket.
-   #
-   # The 'docker' hostname is the alias of the service container as described at
-   # https://docs.gitlab.com/ee/ci/docker/using_docker_images.html#accessing-the-services
-   #
-   # Note that if you're using the Kubernetes executor, the variable should be set to
-   # tcp://localhost:2375/ because of how the Kubernetes executor connects services
-   # to the job container
-   # DOCKER_HOST: tcp://localhost:2375/
-   #
-   # For non-Kubernetes executors, we use tcp://docker:2375/
-   DOCKER_HOST: tcp://docker:2375/
-   # When using dind, it's wise to use the overlayfs driver for
-   # improved performance.
-   DOCKER_DRIVER: overlay2
+  CI_REGISTRY_IMAGE: $CI_REGISTRY/caosdb-server-testenv:latest
+  # With dind the docker deamon is available on the network
+  DOCKER_HOST: tcp://docker:2375/
+  # When using dind, it's wise to use the overlayfs driver for
+  # improved performance.
+  DOCKER_DRIVER: overlay2
 
 services:
-   - docker:dind
+  - docker:dind
 
 image: $CI_REGISTRY_IMAGE
 stages:
-    - setup
-    - test
-    - deploy
+  - setup
+  - test
+  - deploy
 
+# run unit tests of the server
 test:
-    stage: test
-    script:
-        - make easy-units
-        - mvn dependency:purge-local-repository
-        - mvn antlr4:antlr4
-        - mvn compile
-        - echo "defaultRealm = CaosDB" > conf/ext/usersources.ini
-        - mvn test
+  tags: [ docker ]
+  stage: test
+  script:
+    - make easy-units
+    - mvn dependency:purge-local-repository
+    - mvn antlr4:antlr4
+    - mvn compile
+    - echo "defaultRealm = CaosDB" > conf/ext/usersources.ini
+    - mvn test
 
+# Trigger building of server image and integration tests
 trigger_build:
+  tags: [ docker ]
   stage: deploy
   script:
     - /usr/bin/curl -X POST
-       -F token=8f29e5eeb7db2123d9c2bb84634da2
-       -F "variables[SERVER]=$CI_COMMIT_REF_NAME"
-       -F "variables[TriggerdBy]=SERVER"
-       -F ref=master https://gitlab.indiscale.com/api/v4/projects/14/trigger/pipeline
+      -F token=8f29e5eeb7db2123d9c2bb84634da2
+      -F "variables[SERVER]=$CI_COMMIT_REF_NAME"
+      -F "variables[TriggerdBy]=SERVER"
+       -F "variables[TriggerdByHash]=$CI_COMMIT_SHORT_SHA"
+      -F ref=master https://gitlab.indiscale.com/api/v4/projects/14/trigger/pipeline
 
+# Build a docker image in which tests for this repository can run
 build-testenv:
-    image: docker:latest
-    stage: setup
-    script: 
-        - cd src/test/docker
-        - docker login -u testuser -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
-          # use here general latest or specific branch latest...
-        - docker pull $CI_REGISTRY_IMAGE || true
-        - docker build 
-          --pull
-          --cache-from $CI_REGISTRY_IMAGE 
-          -t $CI_REGISTRY_IMAGE .
-        - docker push $CI_REGISTRY_IMAGE
+  tags: [ docker ]
+  image: docker:latest
+  stage: setup
+  script:
+    - cd src/test/docker
+    - docker login -u testuser -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+      # use here general latest or specific branch latest...
+    - docker pull $CI_REGISTRY_IMAGE || true
+    - docker build
+      --pull
+      --cache-from $CI_REGISTRY_IMAGE
+      -t $CI_REGISTRY_IMAGE .
+    - docker push $CI_REGISTRY_IMAGE