Join robin to cluster

modules/hosts/robin/configuration.nix

@@ -1,5 +1,5 @@
 { self, inputs, ... }: {
-  flake.nixosModules.robinConfiguration = { pkgs, ... }: {
+  flake.nixosModules.robinConfiguration = { pkgs, config, ... }: {
     imports = [
       self.nixosModules.robinHardware
       self.nixosModules.nest
@@ -17,6 +17,8 @@
       traceroute
       neovim
       wget
+      openiscsi # Required for longhorn
+      nfs-utils
     ];
 
     networking.networkmanager.enable = true;
@@ -24,8 +26,29 @@
 
     services = {
       openssh.enable = true;
+
+      openiscsi.enable = true;
+      openiscsi.name = "iqn.2005-10.nixos:${config.networking.hostName}";
+
+      envfs.enable = true;
     };
 
+    # Enable K3s in Agent Mode
+    services.k3s = {
+      enable = true;
+      role = "agent";
+      
+      serverAddr = "https://192.168.1.122:6443"; 
+      tokenFile = "/var/lib/rancher/k3s/join-token";
+    };
+
+    # Fix non-FHS paths for longhorn
+    # This creates persistent symlinks where Longhorn expects to find them.
+    systemd.tmpfiles.rules = [
+      "L+ /usr/bin/iscsiadm - - - - /run/current-system/sw/bin/iscsiadm"
+      "L+ /sbin/iscsiadm    - - - - /run/current-system/sw/bin/iscsiadm"
+    ];
+
     # RAID
     boot.swraid = {
       enable = true;