VEGAS/nix: move to cluster/services/attic and adapt for migration

cluster/services/attic/binary-cache.nix

@@ -8,18 +8,34 @@ let
   port = builtins.head (builtins.tail addrSplit);
 in
 {
-  services.nginx.upstreams.nar-serve.extraConfig = ''
+  services.nginx.upstreams = {
+      nar-serve.extraConfig = ''
       random;
       server ${config.links.nar-serve-self.tuple} fail_timeout=0;
       server ${config.links.nar-serve-nixos-org.tuple} fail_timeout=0;
     '';
+    nix-store.servers = {
+      "${config.links.atticServer.tuple}" = {
+        fail_timeout = 0;
+      };
+      "${host}:${port}" = {
+        fail_timeout = 0;
+        backup = true;
+      };
+    };
+  };
   services.nginx.appendHttpConfig = ''
     proxy_cache_path /var/cache/nginx/nixstore levels=1:2 keys_zone=nixstore:10m max_size=10g inactive=24h use_temp_path=off;
   '';
   services.nginx.virtualHosts."cache.${tools.meta.domain}" = vhosts.basic // {
     locations = {
       "= /".return = "302 /404";
-      "/".proxyPass = "http://${host}:${port}/nix-store$request_uri";
+      "/" = {
+        proxyPass = "http://nix-store/nix-store$request_uri";
+        extraConfig = ''
+          proxy_next_upstream error http_500 http_404;
+        '';
+      };
       "/nix/store" = {
         proxyPass = "http://nar-serve";
         extraConfig = ''

cluster/services/attic/default.nix

@@ -4,7 +4,11 @@
       server = [ "VEGAS" ];
     };
     nixos = {
-      server = ./server.nix;
+      server = [
+        ./server.nix
+        ./binary-cache.nix
+        ./nar-serve.nix
+      ];
     };
   };
 }

hosts/VEGAS/system.nix

@@ -24,8 +24,6 @@
       ./services/jokes
       ./services/mail
       ./services/minecraft
-      ./services/nix/binary-cache.nix
-      ./services/nix/nar-serve.nix
       ./services/reflex
       ./services/sso
       ./services/vault