feat(Dind): Test dind containers

documentation/chapters/templates/container/docker-in-docker.adoc

@@ -0,0 +1,12 @@
+:sourcedir: ../../../../templates/
+
+= Docker in Docker
+
+This template helps to start jobs, that need a docker environment to run.
+Simply expand from this Template.
+
+.container scan template
+[source,yaml]
+----
+include::{sourcedir}container/docker-in-docker.gitlab-ci.yml[]
+----

templates/container/docker-in-docker.gitlab-ci.yml

@@ -0,0 +1,22 @@
+.docker-in-docker:
+  services:
+    - name: docker:20.10.17-dind
+      command:
+        - "--registry-mirror"
+        - "https://nexus.corp.exxcellent.de:18000"
+        - "--insecure-registry"
+        - "nexus.corp.exxcellent.de:18000"
+        - "--insecure-registry"
+        - "gitlab.exxcellent.de:4567"
+        # explicitly disable tls to avoid docker startup interruption
+        - "--tls=false"
+      alias: docker
+  variables:
+    # Instruct Testcontainers to use the daemon of DinD.
+    DOCKER_HOST: "tcp://docker:2375"
+    # Instruct Docker not to start over TLS.
+    DOCKER_TLS_CERTDIR: ""
+    # Improve performance with overlayfs.
+    DOCKER_DRIVER: overlay2
+    # Needed by testcontainers https://www.testcontainers.org/supported_docker_environment/continuous_integration/gitlab_ci/
+    TESTCONTAINERS_HOST_OVERRIDE: "host.docker.internal"

test/docker/test-dind.gitlab-ci.yml

@@ -1,22 +1,12 @@
+include:
+  local: "templates/container/docker-in-docker.gitlab-ci.yml"
+
 stages:
   - verify
 
-services:
-  - name: docker:dind
-    # explicitly disable tls to avoid docker startup interruption
-    command: [ "--tls=false" ]
-    alias: docker
-
-variables:
-  # Instruct Testcontainers to use the daemon of DinD.
-  DOCKER_HOST: "tcp://docker:2375"
-  # Instruct Docker not to start over TLS.
-  DOCKER_TLS_CERTDIR: ""
-  # Improve performance with overlayfs.
-  DOCKER_DRIVER: overlay2
-
 Test-Simple-Dind:
   image: docker:stable
+  extends: .docker-in-docker
   stage: verify
   script:
     - docker run -t alpine echo test