library/roles/docker: Install and customize /etc/default/docker.

docker/defaults/main.yml

@@ -13,3 +13,7 @@ docker_packages:
 
 docker_run_as_docker_user: True
 docker_user_home: /home/docker
+docker_defaults_file: /etc/default/docker
+docker_enable_tcp_socket: False
+docker_tcp_socket_port: 2375
+docker_tcp_socket_host: 127.0.0.1

docker/tasks/pkgs.yml

@@ -14,6 +14,10 @@
       apt: pkg={{ item }} state={{ docker_pkg_status }} update_cache=yes cache_valid_time=3600
       with_items: '{{ docker_packages }}'
 
+    - name: Install the Docker default options
+      template: src=docker-default.j2 dest={{ docker_defaults_file }} owner=root group=root mode=0644
+      notify: Restart docker
+
     - name: Ensure that the service is started and enabled
       service: name=docker state=started enabled=yes
 

docker/templates/docker-default.j2

@@ -0,0 +1,15 @@
+# Customize location of Docker binary (especially for development testing).
+#DOCKERD="/usr/local/bin/dockerd"
+
+
+CUSTOM_DOCKER_SOCKET="-H tcp://{{ docker_tcp_socket_host }}:{{ docker_tcp_socket_port }} -H unix:///var/run/docker.sock"
+#CUSTOM_DOCKER_DNS_SERVERS="--dns 8.8.8.8 --dns 8.8.4.4"
+
+# Use DOCKER_OPTS to modify the daemon startup options.
+DOCKER_OPTS="{% if docker_enable_tcp_socket %}$CUSTOM_DOCKER_SOCKET {% endif %}"
+
+# If you need Docker to use an HTTP proxy, it can also be specified here.
+#export http_proxy="http://127.0.0.1:3128/"
+
+# This is also a handy place to tweak where Docker's temporary files go.
+#export DOCKER_TMPDIR="/mnt/bigdrive/docker-tmp"