Properly update profile when not rebooting microvm

packages.nix

@@ -232,6 +232,10 @@ lib.attrsets.mapAttrs
                 echo "hostname of ${target} was expected to be ${name} but is \$hostname. Aborting to be safe..."
                 exit 2
               fi
+
+              # refresh nix db which is required for nix-env -p ... --set
+              ${discardStringCtx hostConfig.nix.package}/bin/nix-store --load-db < ${discardStringCtx (pkgs.closureInfo { rootPaths = [ hostConfig.system.build.toplevel.outPath ]; })}
+              ${discardStringCtx hostConfig.nix.package}/bin/nix-env -p /nix/var/nix/profiles/system --set ${toplevelOutPath}
               ${toplevelOutPath}/bin/switch-to-configuration "''${@:-switch}"
             END
             # ^ yes, this is required to be like this
@@ -253,6 +257,12 @@ lib.attrsets.mapAttrs
 
           ${hostConfig.system.build.runOnServer} bash -e <<END
           set -eou pipefail
+          hostname=\$(cat /etc/hostname)
+          if [[ "\$hostname" != ${name} ]]; then
+            echo "hostname of ${target} was expected to be ${name} but is \$hostname. Aborting to be safe..."
+            exit 2
+          fi
+
           ${createDirsCopyCurrent name}
 
           ln -sfT ${hostConfig.microvm.declaredRunner} current