add: implement basic server

README.md

@@ -12,8 +12,30 @@ tier N1 VM. That extra hop doesn't matter.
 ## Config
 
 Configure nginx to do what you want, test it. Use any Node IP for your testing.
-This tool accepts an argument (rewrite_string) which will be replaced using these rules:
+This will become the 'template_dir' in the argument to the LB.
 
-1. For each line that contains rewrite string:
+Move that directory to somewhere new, i.e. `/etc/nginx-template/`. Make
-2. Copy the line once per node IP, replacing the string with host IPs
+a symlink from that new directory to the old one (i.e.,
+`ln -s /etc/nginx-template /etc/nginx/`).
 
+Make a workspace directory for this tool; it will write configs to this folder
+before updating the symlink you created above. It needs to be persistent so on
+server reboot the service starts ok (i.e., `mkdir /var/skubelb/`).
+
+Make sure the user running the tool has read access to the template folder, read-write
+access to the workspace folder and config symlink.
+
+Run the server with a command like:
+
+```sh
+skubelb --needle some_node_ip \
+    --workspace_dir /var/skubelb \
+    --config_symlink /etc/nginx \
+    --template_dir /etc/nginx-template
+    --listen 0.0.0.0:8080
+```
+
+Replacing `some_node_ip` with the node IP you used during the initial setup.
+
+Next, configure the Kubernetes nodes to POST `http://loadbalancer:8080/register` when
+they started, and DELETE `http://loadbalancer:8080/register` when they shutdown.