Update tests for optimum efficiency.

.travis.yml

@@ -7,11 +7,8 @@ env:
     - ROLE_NAME: kubernetes
   matrix:
     - MOLECULE_DISTRO: centos7
-      MOLECULE_DOCKER_COMMAND: /usr/lib/systemd/systemd
-    - MOLECULE_DISTRO: ubuntu1604
-      MOLECULE_DOCKER_COMMAND: /lib/systemd/systemd
+    - MOLECULE_DISTRO: ubuntu1804
     - MOLECULE_DISTRO: debian9
-      MOLECULE_DOCKER_COMMAND: /lib/systemd/systemd
 
 install:
   # Install test dependencies.

molecule/default/molecule.yml

@@ -9,11 +9,13 @@ lint:
     config-file: molecule/default/yaml-lint.yml
 platforms:
   - name: instance
-    image: geerlingguy/docker-${MOLECULE_DISTRO:-centos7}-ansible
-    command: ${MOLECULE_DOCKER_COMMAND:-"sleep infinity"}
+    image: "geerlingguy/docker-${MOLECULE_DISTRO:-centos7}-ansible:latest"
+    command: ${MOLECULE_DOCKER_COMMAND:-""}
     volumes:
       - /sys/fs/cgroup:/sys/fs/cgroup:ro
       - /var/lib/docker
+    volumes:
+      - /sys/fs/cgroup:/sys/fs/cgroup:ro
     privileged: true
     pre_build_image: true
 provisioner: