dockerd: Add "log-driver" option

Signed-off-by: Nicola Corna <nicola@corna.info>

utils/dockerd/files/dockerd.init

@@ -175,6 +175,7 @@ process_config() {
 
 	# Don't add these options by default
 	# omission == docker defaults
+	config_get log_driver globals log_driver ""
 	config_get bip globals bip ""
 	config_get registry_mirrors globals registry_mirrors ""
 	config_get hosts globals hosts ""
@@ -189,6 +190,7 @@ process_config() {
 	json_add_string "data-root" "${data_root}"
 	json_add_string "log-level" "${log_level}"
 	json_add_boolean "iptables" "${iptables}"
+	[ -z "${log_driver}" ] || json_add_string "log-driver" "${log_driver}"
 	[ -z "${bip}" ] || json_add_string "bip" "${bip}"
 	[ -z "${registry_mirrors}" ] || json_add_array "registry-mirrors"
 	[ -z "${registry_mirrors}" ] || config_list_foreach globals registry_mirrors json_add_array_string

utils/dockerd/files/etc/config/dockerd

@@ -1,4 +1,5 @@
 # The following settings require a restart of docker to take full effect, A reload will only have partial or no effect:
+# log_driver
 # bip
 # blocked_interfaces
 # extra_iptables_args
@@ -7,6 +8,7 @@
 config globals 'globals'
 #	option alt_config_file '/etc/docker/daemon.json'
 	option data_root '/opt/docker/'
+#	option log_driver 'local'
 	option log_level 'warn'
 	option iptables '1'
 #	list hosts 'unix:///var/run/docker.sock'