{ system , # Use a minimal kernel? minimal ? false , # Ignored config ? null , # Nixpkgs, for qemu, lib and more pkgs, lib , # !!! See comment about args in lib/modules.nix specialArgs ? {} , # NixOS configuration to add to the VMs extraConfigurations ? [] }: with lib; rec { inherit pkgs; # Build a virtual network from an attribute set `{ machine1 = # config1; ... machineN = configN; }', where `machineX' is the # hostname and `configX' is a NixOS system configuration. Each # machine is given an arbitrary IP address in the virtual network. buildVirtualNetwork = nodes: let nodesOut = mapAttrs (n: buildVM nodesOut) (assignIPAddresses nodes); in nodesOut; buildVM = nodes: configurations: import ./eval-config.nix { inherit system specialArgs; modules = configurations ++ extraConfigurations; baseModules = (import ../modules/module-list.nix) ++ [ ../modules/virtualisation/qemu-vm.nix ../modules/testing/test-instrumentation.nix # !!! should only get added for automated test runs { key = "no-manual"; documentation.nixos.enable = false; } { key = "no-revision"; # Make the revision metadata constant, in order to avoid needless retesting. # The human version (e.g. 21.05-pre) is left as is, because it is useful # for external modules that test with e.g. testers.nixosTest and rely on that # version number. config.system.nixos.revision = mkForce "constant-nixos-revision"; } { key = "nodes"; _module.args.nodes = nodes; } ] ++ optional minimal ../modules/testing/minimal-kernel.nix; }; # Given an attribute set { machine1 = config1; ... machineN = # configN; }, sequentially assign IP addresses in the 192.168.1.0/24 # range to each machine, and set the hostname to the attribute name. assignIPAddresses = nodes: let machines = attrNames nodes; machinesNumbered = zipLists machines (range 1 254); nodes_ = forEach machinesNumbered (m: nameValuePair m.fst [ ( { config, nodes, ... }: let interfacesNumbered = zipLists config.virtualisation.vlans (range 1 255); interfaces = forEach interfacesNumbered ({ fst, snd }: nameValuePair "eth${toString snd}" { ipv4.addresses = [ { address = "192.168.${toString fst}.${toString m.snd}"; prefixLength = 24; } ]; }); networkConfig = { networking.hostName = mkDefault m.fst; networking.interfaces = listToAttrs interfaces; networking.primaryIPAddress = optionalString (interfaces != []) (head (head interfaces).value.ipv4.addresses).address; # Put the IP addresses of all VMs in this machine's # /etc/hosts file. If a machine has multiple # interfaces, use the IP address corresponding to # the first interface (i.e. the first network in its # virtualisation.vlans option). networking.extraHosts = flip concatMapStrings machines (m': let config = (getAttr m' nodes).config; in optionalString (config.networking.primaryIPAddress != "") ("${config.networking.primaryIPAddress} " + optionalString (config.networking.domain != null) "${config.networking.hostName}.${config.networking.domain} " + "${config.networking.hostName}\n")); virtualisation.qemu.options = let qemu-common = import ../lib/qemu-common.nix { inherit lib pkgs; }; in flip concatMap interfacesNumbered ({ fst, snd }: qemu-common.qemuNICFlags snd fst m.snd); }; in { key = "ip-address"; config = networkConfig // { # Expose the networkConfig items for tests like nixops # that need to recreate the network config. system.build.networkConfig = networkConfig; }; } ) (getAttr m.fst nodes) ] ); in listToAttrs nodes_; }