DNS in declarative container

I was able to fix this using hte bindMounts container option, like:

  containers.flx_web =
  { autoStart = true;
    privateNetwork = true;
    hostAddress = "192.168.100.10";
    localAddress = "192.168.100.11";
    bindMounts = {
      "/etc/resolv.conf" = {
        hostPath = "/etc/resolv.conf";
        isReadOnly = true;
      };  
    };