Revamp role-config

 - Move role-config service and script in to role/ directory
 - role-config now writes or deletes files to/from /etc/sonic/role/
   directory
 - Services which are role-dependent use 'ConditionPathExists=' to
   determine whether or not to start

Author: jleveque

files/build_templates/dhcp_relay.service.j2

@@ -3,6 +3,7 @@ Description=DHCP relay container
 Requires=docker.service
 After=role-config.service
 After=interfaces-config.service
+ConditionPathExists=/etc/sonic/role/dhcp_relay
 
 [Service]
 User={{ sonicadmin_user }}

files/build_templates/sonic_debian_extension.j2

@@ -130,10 +130,12 @@ sudo cp $IMAGE_CONFIGS/platform/platform-init.service  $FILESYSTEM_ROOT/etc/syst
 sudo LANG=C chroot $FILESYSTEM_ROOT systemctl enable platform-init.service
 sudo cp $IMAGE_CONFIGS/platform/platform-init.sh $FILESYSTEM_ROOT/usr/bin/
 
-# Copy role-config script and service unit file, enable service
-sudo cp $IMAGE_CONFIGS/platform/role-config.service  $FILESYSTEM_ROOT/etc/systemd/system/
+# Copy role-config script and service unit file, enable service and create dir to
+# house files that will be used to conditionally start services based on device role
+sudo cp $IMAGE_CONFIGS/role/role-config.service  $FILESYSTEM_ROOT/etc/systemd/system/
 sudo LANG=C chroot $FILESYSTEM_ROOT systemctl enable role-config.service
-sudo cp $IMAGE_CONFIGS/platform/role-config.sh $FILESYSTEM_ROOT/usr/bin/
+sudo cp $IMAGE_CONFIGS/role/role-config.sh $FILESYSTEM_ROOT/usr/bin/
+sudo mkdir -p $FILESYSTEM_ROOT/etc/sonic/role/
 
 # Copy sudoers configuration file
 sudo cp $IMAGE_CONFIGS/sudoers/sudoers $FILESYSTEM_ROOT/etc/

files/build_templates/teamd.service.j2

@@ -3,6 +3,7 @@ Description=TEAMD container
 Requires=database.service
 After=role-config.service
 After=database.service
+ConditionPathExists=/etc/sonic/role/teamd
 
 [Service]
 User={{ sonicadmin_user }}

files/image_config/platform/role-config.service renamed to files/image_config/role/role-config.service

@@ -7,25 +7,27 @@
 #
 
 # Disable DHCP relay service if device does not require it
+DHCP_RELAY_SERVICE_START_FILE=/etc/sonic/role/dhcp_relay
 DEVICE_ROLE=`sonic-cfggen -m /etc/sonic/minigraph.xml -v "minigraph_devices[minigraph_hostname]['type']"`
 
 if [ $DEVICE_ROLE == "ToRRouter" ]; then
-    echo "Device requires DHCP relay. Enabling DHCP relay service..."
-    systemctl enable dhcp_relay.service
+    echo "Device requires DHCP relay service. Ensuring start file exists..."
+    touch $DHCP_RELAY_SERVICE_START_FILE
 else
-    echo "Device does not require DHCP relay. Disabling DHCP relay service..."
-    systemctl disable dhcp_relay.service
+    echo "Device does not require DHCP relay service. Deleting start file..."
+    rm -f $DHCP_RELAY_SERVICE_START_FILE
 fi
 
 
 # Disable teamd service if device does not require it
+TEAMD_SERVICE_START_FILE=/etc/sonic/role/teamd
 NUM_PORTCHANNELS=`sonic-cfggen -m /etc/sonic/minigraph.xml -v "minigraph_portchannels.keys() | count"`
 
 if [ $NUM_PORTCHANNELS -gt 0 ]; then
-    echo "Device requires teamd. Enabling teamd service..."
-    systemctl enable teamd.service
+    echo "Device requires teamd service. Ensuring start file exists..."
+    touch $TEAMD_SERVICE_START_FILE
 else
-    echo "Device does not require teamd. Disabling teamd service..."
-    systemctl disable teamd.service
+    echo "Device does not require teamd service. Deleting start file..."
+    rm -f $TEAMD_SERVICE_START_FILE
 fi