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nixpkgs/nixos/lib/build-vms.nix
2021-10-17 23:56:52 +02:00

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4.3 KiB
Nix

{ 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. 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_;
}