(partially) automate cluster join

Signed-off-by: kayos@tcp.direct <kayos@tcp.direct>

provision.sh

@@ -156,8 +156,11 @@ function user_ops() {
 function lxc_ops() {
 	echo -e "$_SUBUID" >>/etc/subuid || return 1
 	echo -e "$_SUBGID" >>/etc/subgid || return 1
+
 	snap install lxd || return 1
-	lxd init
+
+	# non destructive - if pre-existing it will fail
+	lxd init --auto --storage-backend btrfs --storage-create-device /dev/sda3
 }
 function log() {
 	_date="\e[90m[$(date -u +'%H:%M:%S')]${RESET}"