NFS server and client setup.

hosts/c1/default.nix

@@ -4,6 +4,11 @@
     ../../common/encrypted-btrfs-layout.nix
     ../../common/global
     ../../common/compute-node.nix
+    ../../common/nfs-services-standby.nix  # NFS standby for /data/services
+    # To promote to NFS server (during failover):
+    # 1. Follow procedure in docs/NFS_FAILOVER.md
+    # 2. Replace above line with: ../../common/nfs-services-server.nix
+    # 3. Add nfsServicesServer.standbys = [ "c2" ]; (or leave empty)
     ./hardware.nix
   ];
 
@@ -15,4 +20,9 @@
 
   networking.hostName = "c1";
   services.tailscaleAutoconnect.authkey = "tskey-auth-k2nQ771YHM11CNTRL-YVpoumL2mgR6nLPG51vNhRpEKMDN7gLAi";
+
+  # NFS standby configuration: accept replication from zippy
+  nfsServicesStandby.replicationKeys = [
+    "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHyTKsMCbwCIlMcC/aopgz5Yfx/Q9QdlWC9jzMLgYFAV root@zippy-replication"
+  ];
 }