Merge pull request #3493 from edx/bilalahmad99/discovery-16.04-docker

for discovery 16.04 docker image

docker/build/discovery/Dockerfile

@@ -7,7 +7,7 @@
 # This allows the dockerfile to update /edx/app/edx_ansible/edx_ansible
 # with the currently checked-out configuration repo.
 
-FROM edxops/trusty-common:latest
+FROM edxops/xenial-common:latest
 MAINTAINER edxops
 
 ENV DISCOVERY_VERSION=master

playbooks/roles/discovery/templates/edx/app/discovery/devstack.sh.j2

@@ -7,15 +7,28 @@ COMMAND=$1
 
 case $COMMAND in
     start)
-        {% set discovery_venv_bin = discovery_home + "/venvs/" + discovery_service_name + "/bin" %}
+        {% set discovery_venv_bin = discovery_venv_dir + "/bin" %}
 
         {{ supervisor_venv_bin }}/supervisord --configuration {{ supervisor_cfg }}
 
+	# Needed to run bower as root. See explaination around 'discovery_user=root'
+	echo '{ "allow_root": true }' > /root/.bowerrc
+
         cd /edx/app/edx_ansible/edx_ansible/docker/plays
-        ansible-playbook discovery.yml -c local -i '127.0.0.1,' \
-            -t 'install:app-requirements,assets:gather,devstack,migrate,manage:start' \
+        /edx/app/edx_ansible/venvs/edx_ansible/bin/ansible-playbook discovery.yml -c local -i '127.0.0.1,' \
+            -t 'install:app-requirements,assets:gather,devstack,migrate' \
             --extra-vars="migrate_db=yes" \
-            --extra-vars="@/ansible_overrides.yml"
+            --extra-vars="@/ansible_overrides.yml" \
+	    --extra-vars="discovery_user=root"  # Needed when sharing the volume with the host machine because node/bower drops
+						# everything in the code directory by default.  So we get issues with permissions
+						# on folders owned by the developer.
+
+
+	# Need to start supervisord and nginx manually because systemd is hard to run on docker
+	# http://developers.redhat.com/blog/2014/05/05/running-systemd-within-docker-container/
+	# Both daemon by default
+	nginx
+	/edx/app/supervisor/venvs/supervisor/bin/supervisord --configuration /edx/app/supervisor/supervisord.conf
 
         # Docker requires an active foreground task. Tail the logs to appease Docker and
         # provide useful output for development.