diff --git a/nixos/lib/build-vms.nix b/nixos/lib/build-vms.nix
index d20fbc1cc66..498c0a37783 100644
--- a/nixos/lib/build-vms.nix
+++ b/nixos/lib/build-vms.nix
@@ -68,8 +68,8 @@ rec {
                   # the first interface (i.e. the first network in its
                   # virtualisation.vlans option).
                   networking.extraHosts = flip concatMapStrings machines
-                    (m: let config = (getAttr m nodes).config; in
-                      optionalString (config.networking.primaryIPAddress != "")
+                    (m': let config = (getAttr m' nodes).config; in
+                      optionalString (m.first != m' && config.networking.primaryIPAddress != "")
                         ("${config.networking.primaryIPAddress} " +
                          "${config.networking.hostName}\n"));
 
diff --git a/nixos/tests/misc.nix b/nixos/tests/misc.nix
index 12ac6f6f9a6..d355d705a24 100644
--- a/nixos/tests/misc.nix
+++ b/nixos/tests/misc.nix
@@ -59,6 +59,12 @@
       subtest "override-env-var", sub {
           $machine->succeed('[ "$EDITOR" = emacs ]');
       };
+
+      # Test whether hostname (and by extension nss_myhostname) works.
+      subtest "hostname", sub {
+          $machine->succeed('[ "`hostname`" = machine ]');
+          $machine->succeed('[ "`hostname -s`" = machine ]');
+      };
     '';
 
 }