Modular, context-aware and aspect-oriented dendritic Nix configurations.
Discussions: https://oeiuwq.zulipchat.com/join/nqp26cd4kngon6mo3ncgnuap/
den.oeiuwq.com
configurations
den
dendritic
nix
aspect
oriented
feat(template): MicroVM example integration (#240)
authored by
GitHub
9dd55dc1
a63a4c3b
+9
-25
.github/workflows/test.yml
+9
-25
.github/workflows/test.yml
···
75
75
EOF
76
76
git add templates/noflake/modules/ci-runtime.nix
77
77
- run: cd templates/noflake && nix-build -A flake.nixosConfigurations.igloo.config.system.build.toplevel
78
-
minimal:
79
-
needs: [approved]
80
-
name: minimal
81
-
runs-on: ubuntu-latest
82
-
steps:
83
-
- uses: wimpysworld/nothing-but-nix@main
84
-
- uses: cachix/install-nix-action@v31
85
-
- uses: DeterminateSystems/magic-nix-cache-action@v13
86
-
- uses: actions/checkout@v4
87
-
- run: |
88
-
cat <<-EOF > templates/minimal/modules/ci-runtime.nix
89
-
{
90
-
_module.args.CI = true;
91
-
}
92
-
EOF
93
-
git add templates/minimal/modules/ci-runtime.nix
94
-
- run: nix flake check -L ./templates/minimal --override-input den github:$GITHUB_REPOSITORY/$GITHUB_SHA
95
-
bogus:
78
+
template:
96
79
needs: [approved]
97
80
strategy:
98
81
matrix:
99
-
os: [ubuntu-latest, macos-latest]
100
-
name: Bogus ${{matrix.os}}
82
+
template: [bogus, minimal, microvm]
83
+
os: [ubuntu-latest]
84
+
name: Check template ${{matrix.template}} ${{matrix.os}}
101
85
runs-on: ${{matrix.os}}
102
86
steps:
103
87
- uses: wimpysworld/nothing-but-nix@main
···
105
89
- uses: DeterminateSystems/magic-nix-cache-action@v13
106
90
- uses: actions/checkout@v4
107
91
- run: |
108
-
cat <<-EOF > templates/bogus/modules/ci-runtime.nix
92
+
cat <<-EOF > templates/${{matrix.template}}/modules/ci-runtime.nix
109
93
{
110
94
_module.args.CI = true;
111
95
}
112
96
EOF
113
-
git add templates/bogus/modules/ci-runtime.nix
114
-
- run: nix flake check -L ./templates/bogus --override-input den github:$GITHUB_REPOSITORY/$GITHUB_SHA
115
-
template:
97
+
git add templates/${{matrix.template}}/modules/ci-runtime.nix
98
+
- run: nix flake check -L ./templates/${{matrix.template}} --override-input den github:$GITHUB_REPOSITORY/$GITHUB_SHA
99
+
flake-file-template:
116
100
needs: [approved]
117
101
strategy:
118
102
# max-parallel: 1
119
103
matrix:
120
-
os: [ubuntu-latest, macos-latest]
104
+
os: [ubuntu-latest]
121
105
template: [default, example]
122
106
name: Check template ${{matrix.template}} ${{matrix.os}}
123
107
runs-on: ${{matrix.os}}
+8
-1
modules/config.nix
+8
-1
modules/config.nix
···
9
9
builder: cfg:
10
10
let
11
11
items = map builtins.attrValues (builtins.attrValues cfg);
12
-
buildItem = item: lib.setAttrByPath item.intoAttr (builder item);
12
+
buildItem =
13
+
item:
14
+
if
15
+
item.intoAttr == [ ] # no output requested
16
+
then
17
+
{ }
18
+
else
19
+
lib.setAttrByPath item.intoAttr (builder item);
13
20
built = map buildItem (lib.flatten items);
14
21
in
15
22
built;
+5
-1
nix/ctx-apply.nix
+5
-1
nix/ctx-apply.nix
···
26
26
]
27
27
++ lib.concatLists (
28
28
lib.mapAttrsToList (
29
-
name: into: lib.concatMap (transformAll self den.ctx.${name}) (into ctx)
29
+
name: into:
30
+
if !builtins.hasAttr name den.ctx then
31
+
[ ]
32
+
else
33
+
lib.concatMap (transformAll self den.ctx.${name}) (into ctx)
30
34
) self.into
31
35
);
32
36
+2
nix/default.nix
+2
nix/default.nix
···
17
17
noflake.description = "Den without flake";
18
18
example.path = ../templates/example;
19
19
example.description = "Example";
20
+
microvm.path = ../templates/microvm;
21
+
microvm.description = "MicroVM example";
20
22
ci.path = ../templates/ci;
21
23
ci.description = "Feature Tests";
22
24
bogus.path = ../templates/bogus;
+26
templates/microvm/README.md
+26
templates/microvm/README.md
···
1
+
# MicroVM in Den examples
2
+
3
+
There are two ways to run VMs:
4
+
5
+
## NixOS configuration MicroVM runner as package.
6
+
7
+
- Den example: [runnable-example.nix](./modules/runnable-example.nix)
8
+
- Den support: [microvm-runners.nix](./modules/microvm-runners.nix)
9
+
10
+
```console
11
+
nix run .#runnable-microvm
12
+
```
13
+
14
+
See https://microvm-nix.github.io/microvm.nix/packages.html
15
+
16
+
## MicroVM guests as part of a Host.
17
+
18
+
- Den example: [guests-example.nix](./modules/guests-example.nix)
19
+
- Den support: [microvm-integration.nix](./modules/microvm-integration.nix)
20
+
21
+
```console
22
+
nixos-rebuild build --flake .#server
23
+
```
24
+
25
+
See https://microvm-nix.github.io/microvm.nix/host.html\
26
+
https://microvm-nix.github.io/microvm.nix/declarative.html
+113
templates/microvm/flake.lock
+113
templates/microvm/flake.lock
···
1
+
{
2
+
"nodes": {
3
+
"den": {
4
+
"locked": {
5
+
"lastModified": 1772891845,
6
+
"narHash": "sha256-sh0T1cJt45S8FM1RS0goajFfbQ/oop8XfIU8iG6Ww1k=",
7
+
"owner": "vic",
8
+
"repo": "den",
9
+
"rev": "a63a4c3bb5ea2674cd8b941635e63afbc5a4bc9f",
10
+
"type": "github"
11
+
},
12
+
"original": {
13
+
"owner": "vic",
14
+
"repo": "den",
15
+
"type": "github"
16
+
}
17
+
},
18
+
"flake-aspects": {
19
+
"locked": {
20
+
"lastModified": 1772749648,
21
+
"narHash": "sha256-6QtwbL/R0RhJrHIDc1SdJD0YYfVXG9yteiFkfNl0Rbg=",
22
+
"owner": "vic",
23
+
"repo": "flake-aspects",
24
+
"rev": "ccc25fc1e06b8957e15e6d0c0a0c51e9d7a96b37",
25
+
"type": "github"
26
+
},
27
+
"original": {
28
+
"owner": "vic",
29
+
"repo": "flake-aspects",
30
+
"type": "github"
31
+
}
32
+
},
33
+
"import-tree": {
34
+
"locked": {
35
+
"lastModified": 1772344373,
36
+
"narHash": "sha256-OQQ1MhB9t1J71b2wxRRTdH/Qd8UGG0p+dGspfCf5U1c=",
37
+
"owner": "vic",
38
+
"repo": "import-tree",
39
+
"rev": "10fda59eee7d7970ec443b925f32a1bc7526648c",
40
+
"type": "github"
41
+
},
42
+
"original": {
43
+
"owner": "vic",
44
+
"repo": "import-tree",
45
+
"type": "github"
46
+
}
47
+
},
48
+
"microvm": {
49
+
"inputs": {
50
+
"nixpkgs": [
51
+
"nixpkgs"
52
+
],
53
+
"spectrum": "spectrum"
54
+
},
55
+
"locked": {
56
+
"lastModified": 1772922713,
57
+
"narHash": "sha256-+dn2D7gNrrld3q/AapoZZ6HL8xnBS/pcV4Gye1Nfsg0=",
58
+
"owner": "microvm-nix",
59
+
"repo": "microvm.nix",
60
+
"rev": "6207a74a1ec31d3aa628cb98eb75795a10f49dea",
61
+
"type": "github"
62
+
},
63
+
"original": {
64
+
"owner": "microvm-nix",
65
+
"repo": "microvm.nix",
66
+
"type": "github"
67
+
}
68
+
},
69
+
"nixpkgs": {
70
+
"locked": {
71
+
"lastModified": 1772736753,
72
+
"narHash": "sha256-au/m3+EuBLoSzWUCb64a/MZq6QUtOV8oC0D9tY2scPQ=",
73
+
"owner": "nixos",
74
+
"repo": "nixpkgs",
75
+
"rev": "917fec990948658ef1ccd07cef2a1ef060786846",
76
+
"type": "github"
77
+
},
78
+
"original": {
79
+
"owner": "nixos",
80
+
"ref": "nixpkgs-unstable",
81
+
"repo": "nixpkgs",
82
+
"type": "github"
83
+
}
84
+
},
85
+
"root": {
86
+
"inputs": {
87
+
"den": "den",
88
+
"flake-aspects": "flake-aspects",
89
+
"import-tree": "import-tree",
90
+
"microvm": "microvm",
91
+
"nixpkgs": "nixpkgs"
92
+
}
93
+
},
94
+
"spectrum": {
95
+
"flake": false,
96
+
"locked": {
97
+
"lastModified": 1759482047,
98
+
"narHash": "sha256-H1wiXRQHxxPyMMlP39ce3ROKCwI5/tUn36P8x6dFiiQ=",
99
+
"ref": "refs/heads/main",
100
+
"rev": "c5d5786d3dc938af0b279c542d1e43bce381b4b9",
101
+
"revCount": 996,
102
+
"type": "git",
103
+
"url": "https://spectrum-os.org/git/spectrum"
104
+
},
105
+
"original": {
106
+
"type": "git",
107
+
"url": "https://spectrum-os.org/git/spectrum"
108
+
}
109
+
}
110
+
},
111
+
"root": "root",
112
+
"version": 7
113
+
}
+27
templates/microvm/flake.nix
+27
templates/microvm/flake.nix
···
1
+
{
2
+
# Den adapted from default microvm template.
3
+
description = "NixOS in MicroVMs with Den";
4
+
5
+
nixConfig = {
6
+
extra-substituters = [ "https://microvm.cachix.org" ];
7
+
extra-trusted-public-keys = [ "microvm.cachix.org-1:oXnBc6hRE3eX5rSYdRyMYXnfzcCxC7yKPTbZXALsqys=" ];
8
+
};
9
+
10
+
inputs.den.url = "github:vic/den";
11
+
inputs.flake-aspects.url = "github:vic/flake-aspects";
12
+
inputs.import-tree.url = "github:vic/import-tree";
13
+
14
+
inputs.nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
15
+
16
+
inputs.microvm = {
17
+
url = "github:microvm-nix/microvm.nix";
18
+
inputs.nixpkgs.follows = "nixpkgs";
19
+
};
20
+
21
+
outputs =
22
+
inputs:
23
+
(inputs.nixpkgs.lib.evalModules {
24
+
modules = [ (inputs.import-tree ./modules) ];
25
+
specialArgs = { inherit inputs; };
26
+
}).config.flake;
27
+
}
+21
templates/microvm/modules/den.nix
+21
templates/microvm/modules/den.nix
···
1
+
{ den, inputs, ... }:
2
+
{
3
+
imports = [ inputs.den.flakeModule ];
4
+
5
+
#
6
+
# There are two ways to run VMS:
7
+
#
8
+
# - NixOS configuration MicroVM runner as package.
9
+
# Den example: ./runnable-example.nix (by ./microvm-runners.nix)
10
+
# See https://microvm-nix.github.io/microvm.nix/packages.html
11
+
#
12
+
#
13
+
# - MicroVM guests as part of a Host.
14
+
# Den example: ./guests-example.nix (by ./microvm-integration.nix)
15
+
# See https://microvm-nix.github.io/microvm.nix/host.html
16
+
# https://microvm-nix.github.io/microvm.nix/declarative.html
17
+
#
18
+
19
+
# automatically set hostname on all hosts.
20
+
den.ctx.host.includes = [ den._.hostname ];
21
+
}
+38
templates/microvm/modules/guests-example.nix
+38
templates/microvm/modules/guests-example.nix
···
1
+
{ den, lib, ... }:
2
+
{
3
+
4
+
den.hosts.x86_64-linux.server.microvm.guests = [
5
+
den.hosts.x86_64-linux.guest-microvm
6
+
];
7
+
8
+
den.hosts.x86_64-linux.guest-microvm = {
9
+
intoAttr = [ ]; # dont produce Guest nixosConfiguration at flake output
10
+
};
11
+
12
+
den.aspects.no-boot.nixos = {
13
+
boot.loader.grub.enable = false;
14
+
fileSystems."/".device = "/dev/null";
15
+
};
16
+
17
+
den.aspects.server = {
18
+
# USER TODO: remove this on real bootable server
19
+
includes = [ den.aspects.no-boot ];
20
+
21
+
# NOTE: no microvm class exist for Host, only for Guests
22
+
nixos.microvm.host.startupTimeout = 300;
23
+
};
24
+
25
+
den.aspects.guest-microvm = {
26
+
# resolved with: `(den.ctx.host = { host = guest-microvm }).resolve { class = "nixos" }`
27
+
# resulting nixos-module is set at server: microvm.vms.<name>.config
28
+
nixos =
29
+
{ pkgs, ... }:
30
+
{
31
+
environment.systemPackages = [ pkgs.cowsay ];
32
+
};
33
+
34
+
# microvm class is for Guests!, forwarded into server: nixos.microvm.vms.<name>
35
+
microvm.autostart = true;
36
+
};
37
+
38
+
}
+116
templates/microvm/modules/microvm-integration.nix
+116
templates/microvm/modules/microvm-integration.nix
···
1
+
{
2
+
den,
3
+
lib,
4
+
config,
5
+
inputs,
6
+
...
7
+
}:
8
+
let
9
+
# extends den.schema.host with MicroVM specific options
10
+
extendHostSchema =
11
+
{ host, ... }:
12
+
{
13
+
options.microvm.module = lib.mkOption {
14
+
description = "MicroVM microvm.nix module";
15
+
type = lib.types.deferredModule;
16
+
default = inputs.microvm."${host.class}Modules".microvm;
17
+
};
18
+
19
+
options.microvm.hostModule = lib.mkOption {
20
+
description = "MicroVM host.nix module";
21
+
type = lib.types.deferredModule;
22
+
default = inputs.microvm."${host.class}Modules".host;
23
+
};
24
+
25
+
# Declarative Guest VMs built with Host.
26
+
options.microvm.guests = lib.mkOption {
27
+
type = lib.types.listOf lib.types.raw;
28
+
default = [ ];
29
+
description = ''
30
+
Guest MicroVMs.
31
+
Value is a list of Den hosts: [ den.hosts.x86_64-linux.foo-microvm ]
32
+
33
+
When non empty, Host imports <microvm>/host.nix module
34
+
and starts our Den microvm-host context pipeline.
35
+
36
+
See: https://microvm-nix.github.io/microvm.nix/host.html
37
+
https://microvm-nix.github.io/microvm.nix/declarative.html
38
+
'';
39
+
};
40
+
41
+
options.microvm.sharedNixStore = lib.mkEnableOption "Auto share nix store from host";
42
+
config.microvm.sharedNixStore = lib.mkDefault true;
43
+
};
44
+
45
+
# transition a NixOS host into a MicroVM host (only if it has guest microvms)
46
+
ctx.host.into.microvm-host = { host }: lib.optional (host.microvm.guests != [ ]) { inherit host; };
47
+
48
+
# aspect configuring a MicroVM host. imports the microvm host.nix module.
49
+
ctx.microvm-host.provides.microvm-host =
50
+
{ host }:
51
+
{
52
+
${host.class}.imports = [ host.microvm.hostModule ];
53
+
};
54
+
55
+
# transition from microvm host into each microvm guest
56
+
ctx.microvm-host.into.microvm-guest = { host }: map (vm: { inherit host vm; }) host.microvm.guests;
57
+
58
+
# aspect configuring a guest vm at the host level (Declarative in MicroVM parlance)
59
+
# See: https://microvm-nix.github.io/microvm.nix/declarative.html
60
+
ctx.microvm-host.provides.microvm-guest =
61
+
{ host, vm }:
62
+
{
63
+
includes =
64
+
let
65
+
sharedNixStore = lib.optionalAttrs host.microvm.sharedNixStore {
66
+
${host.class}.microvm.vms.${vm.name}.config.microvm.shares = [
67
+
{
68
+
source = "/nix/store";
69
+
mountPoint = "/nix/.ro-store";
70
+
tag = "ro-store";
71
+
proto = "virtiofs";
72
+
}
73
+
];
74
+
};
75
+
76
+
# forwards guest nixos configuration into host: microvm.vms.<vm-name>.config
77
+
osFwd = den.provides.forward {
78
+
each = lib.singleton true;
79
+
fromClass = _: vm.class;
80
+
intoClass = _: host.class;
81
+
intoPath = _: [
82
+
"microvm"
83
+
"vms"
84
+
vm.name
85
+
"config"
86
+
];
87
+
# calling host-pipeline ensure all Den features supported on guest
88
+
fromAspect = _: den.ctx.host { host = vm; };
89
+
};
90
+
91
+
# forwards guest microvm class into host: microvm.vms.<vm-name>
92
+
microvmClass = den.provides.forward {
93
+
each = lib.singleton true;
94
+
fromClass = _: "microvm";
95
+
intoClass = _: host.class;
96
+
intoPath = _: [
97
+
"microvm"
98
+
"vms"
99
+
vm.name
100
+
];
101
+
fromAspect = _: den.aspects.${vm.aspect};
102
+
};
103
+
104
+
in
105
+
[
106
+
sharedNixStore
107
+
osFwd
108
+
microvmClass
109
+
];
110
+
};
111
+
112
+
in
113
+
{
114
+
den.ctx = ctx;
115
+
den.schema.host.imports = [ extendHostSchema ];
116
+
}
+32
templates/microvm/modules/microvm-runners.nix
+32
templates/microvm/modules/microvm-runners.nix
···
1
+
# for each host exposes microvm declaredRunner (if exists) as package output of this flake.
2
+
# feel free to remove or adapt.
3
+
{
4
+
den,
5
+
lib,
6
+
config,
7
+
...
8
+
}:
9
+
let
10
+
# omit if you are using flake-parts. create a packages output for us.
11
+
packagesModule.options.flake.packages = lib.mkOption { };
12
+
13
+
microvmRunners = lib.pipe den.hosts [
14
+
lib.attrValues
15
+
(lib.concatMap lib.attrValues)
16
+
(map (
17
+
host:
18
+
let
19
+
osConf = lib.attrByPath host.intoAttr null config.flake;
20
+
vmRunner = osConf.config.microvm.declaredRunner or null;
21
+
package = lib.optionalAttrs (vmRunner != null) {
22
+
${host.system}.${host.name} = vmRunner;
23
+
};
24
+
in
25
+
package
26
+
))
27
+
];
28
+
in
29
+
{
30
+
imports = [ packagesModule ];
31
+
flake.packages = lib.mkMerge microvmRunners;
32
+
}
+54
templates/microvm/modules/runnable-example.nix
+54
templates/microvm/modules/runnable-example.nix
···
1
+
# Copied from MicroVM flake template.
2
+
#
3
+
# This is just a normal NixOS configuration that happes to include microvm.nix module.
4
+
# No special Den classes nor context pipeline here. It's all just a single NixOS conf.
5
+
# Den support: ./microvm-runners.nix
6
+
#
7
+
{
8
+
inputs,
9
+
den,
10
+
lib,
11
+
...
12
+
}:
13
+
{
14
+
15
+
den.hosts.x86_64-linux.runnable-microvm = {
16
+
intoAttr = [
17
+
"microvms"
18
+
"runnable-microvm"
19
+
]; # example not intended to be used from nixosConfigurations
20
+
};
21
+
22
+
den.aspects.runnable-microvm = {
23
+
nixos = {
24
+
imports = [ inputs.microvm.nixosModules.microvm ];
25
+
users.users.root.password = "";
26
+
27
+
# There's not much need to have a forwarding microvm class for runnable vms
28
+
microvm = {
29
+
volumes = [
30
+
{
31
+
mountPoint = "/var";
32
+
image = "var.img";
33
+
size = 256;
34
+
}
35
+
];
36
+
shares = [
37
+
{
38
+
# use proto = "virtiofs" for MicroVMs that are started by systemd
39
+
proto = "9p";
40
+
tag = "ro-store";
41
+
# a host's /nix/store will be picked up so that no
42
+
# squashfs/erofs will be built for it.
43
+
source = "/nix/store";
44
+
mountPoint = "/nix/.ro-store";
45
+
}
46
+
];
47
+
48
+
# "qemu" has 9p built-in!
49
+
hypervisor = "qemu";
50
+
socket = "control.socket";
51
+
};
52
+
};
53
+
};
54
+
}
+3
-3
templates/minimal/flake.lock
+3
-3
templates/minimal/flake.lock
···
2
2
"nodes": {
3
3
"den": {
4
4
"locked": {
5
-
"lastModified": 1772737374,
6
-
"narHash": "sha256-b1nHLbA42NXPSPC6lpP2K/9RVwO+z91AVV44yRycO5c=",
5
+
"lastModified": 1772891845,
6
+
"narHash": "sha256-sh0T1cJt45S8FM1RS0goajFfbQ/oop8XfIU8iG6Ww1k=",
7
7
"owner": "vic",
8
8
"repo": "den",
9
-
"rev": "57aef3045c87527e94f1f139a818f8851e024a33",
9
+
"rev": "a63a4c3bb5ea2674cd8b941635e63afbc5a4bc9f",
10
10
"type": "github"
11
11
},
12
12
"original": {