Merge branch 'master' into frcc-kvm

.github/workflows/lint.yml

@@ -19,18 +19,18 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: pick reporter
+        run: |
+          if [ "${{ github.event_name }}" = pull_request ]; then
+            echo "REPORTER=github-pr-review" >> "$GITHUB_ENV"
+          else
+            echo "REPORTER=local" >> "$GITHUB_ENV"
+          fi
+
       - name: run linters
         run: nix run -L .#ci -- lint . "$RUNNER_TEMP/findings"
 
       - name: report findings
-        if: always()
         env:
-          REVIEWDOG_GITEA_API_TOKEN: ${{ secrets.GITEA_TOKEN }}
-          GITEA_ADDRESS: ${{ github.server_url }}
-        run: |
-          if [ "${{ github.event_name }}" = pull_request ]; then
-            nix run -L .#ci -- lint-report gitea-pr-review "$RUNNER_TEMP/findings"
-          else
-            nix run -L .#ci -- lint-summary "$RUNNER_TEMP/findings" \
-              | tee -a "$GITHUB_STEP_SUMMARY"
-          fi
+          REVIEWDOG_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: nix run -L .#ci -- lint-report "$REPORTER" "$RUNNER_TEMP/findings"

ci.nix

@@ -3,7 +3,6 @@
 # runner's own nix, not a pinned one).
 pkgs.writers.writePython3Bin "ci" {
   flakeIgnore = [ "E501" ];
-  libraries = [ pkgs.python3Packages.subprocess-tee ];
   makeWrapperArgs = [
     "--prefix"
     "PATH"

ci.py

@@ -6,7 +6,6 @@ import json
 import os
 import re
 import subprocess
-import subprocess_tee
 import sys
 import urllib.request
 from collections import Counter
@@ -18,7 +17,7 @@ def run(*args, **kw):
 
 
 def nix(*args):
-    return subprocess_tee.run(("nix", "--extra-experimental-features", "nix-command flakes", "-L", *args), check=True, text=True).stdout
+    return run("nix", "--extra-experimental-features", "nix-command flakes", "-L", *args, check=True, stdout=subprocess.PIPE).stdout
 
 
 def git(*args, check=True):
@@ -363,63 +362,10 @@ def lint_report(args):
 
     codes = [reviewdog(f"{args.dir}/{name}", flags)
              for name, flags in LINTERS
-             if os.path.isfile(f"{args.dir}/{name}") and os.path.getsize(f"{args.dir}/{name}") > 0]
+             if os.path.getsize(f"{args.dir}/{name}") > 0]
     sys.exit(1 if any(codes) else 0)
 
 
-def has_findings(path):
-    return os.path.isfile(path) and os.path.getsize(path) > 0
-
-
-def fmt_rdjsonl(path):
-    lines = []
-    with open(path) as f:
-        for raw in f:
-            rec = json.loads(raw)
-            loc = rec["location"]
-            r = loc.get("range", {}).get("start")
-            pos = f"{loc['path']}:{r['line']}:{r['column']}" if r else loc["path"]
-            lines.append(f"- `{pos}`: {rec['message']}")
-    return "\n".join(lines)
-
-
-def fmt_errfmt(path):
-    lines = []
-    with open(path) as f:
-        for raw in f:
-            parts = raw.strip().split(">", 1)
-            if len(parts) == 2:
-                lines.append(f"- `{parts[0]}:{parts[1].split(':', 3)[-1].strip()}`" if ":" in parts[1] else f"- `{raw.strip()}`")
-            elif raw.strip():
-                lines.append(f"- `{raw.strip()}`")
-    return "\n".join(lines)
-
-
-def lint_summary(args):
-    sections = []
-    d = args.dir
-
-    if has_findings(f"{d}/nixfmt.diff"):
-        with open(f"{d}/nixfmt.diff") as f:
-            sections.append(f"## nixfmt\n\n```diff\n{f.read().rstrip()}\n```")
-
-    if has_findings(f"{d}/statix.errfmt"):
-        sections.append(f"## statix\n\n{fmt_errfmt(f'{d}/statix.errfmt')}")
-
-    if has_findings(f"{d}/deadnix.rdjsonl"):
-        sections.append(f"## deadnix\n\n{fmt_rdjsonl(f'{d}/deadnix.rdjsonl')}")
-
-    if has_findings(f"{d}/cycles.rdjsonl"):
-        sections.append(f"## systemd ordering cycles\n\n{fmt_rdjsonl(f'{d}/cycles.rdjsonl')}")
-
-    if sections:
-        print("\n\n".join(["# Lint findings"] + sections))
-        sys.exit(1)
-    else:
-        print("No lint findings.")
-        sys.exit(0)
-
-
 def post_comment(args):
     body = args.marker + "\n" + Path(args.body_file).read_text()
     pr = os.environ["PR"]
@@ -492,7 +438,6 @@ def main():
     command("vulnix", vulnix, "ref", "body_out")
     command("lint", lint, "target", "out")
     command("lint-report", lint_report, "reporter", "dir")
-    command("lint-summary", lint_summary, "dir")
     command("post-comment", post_comment, "marker", "body_file")
     command("upsert-issue", upsert_issue, "label", "title", "body_file")
     command("close-issue", close_issue, "label")

containers/common/overseer.nix

@@ -381,6 +381,6 @@ let
         };
       };
     };
-  inherit (c) hostAddr;
+  hostAddr = c.hostAddr;
 in
 c

containers/server-n0/git.nix

@@ -55,179 +55,145 @@ in
     net.expose.tcp = [ 3000 ];
   };
 
-  ci-runner =
-    mkVm {
-      name = "ci-runner";
-      includedInTests = false;
-      net.access = [
-        {
-          to = "git";
-          tcp = [ 3000 ];
-        }
-        { to = "@internet"; }
-      ];
-      svc.autoStart = true;
-      resources.cpu = 4;
-      resources.mem = "32G";
-      resources.fs = [
-        {
-          proto = "virtiofs";
-          tag = "nix-rw-store";
-          source = "${ciRunnerData}/nix-rw-store";
-          mountPoint = "/nix/.rw-store";
-        }
-        {
-          proto = "virtiofs";
-          tag = "nix-db";
-          source = "${ciRunnerData}/nix-db";
-          mountPoint = "/nix/var/nix/db";
-        }
-        {
-          proto = "virtiofs";
-          tag = "docker-data";
-          source = "${ciRunnerData}/docker";
-          mountPoint = "/var/lib/docker";
-        }
-        {
-          proto = "virtiofs";
-          tag = "runner-state";
-          source = "${ciRunnerData}/runner-state";
-          mountPoint = "/var/lib/private/gitea-runner";
-        }
-        {
-          proto = "virtiofs";
-          tag = "runner-token";
-          source = ciRunnerSecrets;
-          mountPoint = "/run/ci-runner-secrets";
-          readOnly = true;
-        }
-        {
-          proto = "virtiofs";
-          tag = "tmp";
-          source = "/tmp";
-          mountPoint = "/tmp";
-        }
-      ];
-      guestConfig =
-        {
-          pkgs,
-          utils,
-          lib,
-          ...
-        }:
-        let
-          runnerInstanceName = "ci-runner";
+  ci-runner = mkVm {
+    name = "ci-runner";
+    includedInTests = false;
+    net.access = [
+      {
+        to = "git";
+        tcp = [ 3000 ];
+      }
+      { to = "@internet"; }
+    ];
+    svc.autoStart = true;
+    resources.cpu = 4;
+    resources.mem = "32G";
+    resources.fs = [
+      {
+        proto = "virtiofs";
+        tag = "nix-rw-store";
+        source = "${ciRunnerData}/nix-rw-store";
+        mountPoint = "/nix/.rw-store";
+      }
+      {
+        proto = "virtiofs";
+        tag = "docker-data";
+        source = "${ciRunnerData}/docker";
+        mountPoint = "/var/lib/docker";
+      }
+      {
+        proto = "virtiofs";
+        tag = "runner-state";
+        source = "${ciRunnerData}/runner-state";
+        mountPoint = "/var/lib/private/gitea-runner";
+      }
+      {
+        proto = "virtiofs";
+        tag = "runner-token";
+        source = ciRunnerSecrets;
+        mountPoint = "/run/ci-runner-secrets";
+        readOnly = true;
+      }
+    ];
+    guestConfig =
+      {
+        pkgs,
+        utils,
+        lib,
+        ...
+      }:
+      let
+        runnerInstanceName = "ci-runner";
 
-          ciJobContents = with pkgs; [
-            bashInteractive
-            coreutils
-            gitMinimal
-            nixVersions.latest
-            nodejs
-            cacert
-            (writeTextDir "etc/nix/nix.conf" "experimental-features = nix-command flakes\n")
-          ];
+        ciJobContents = with pkgs; [
+          bashInteractive
+          coreutils
+          gitMinimal
+          nixVersions.latest
+          nodejs
+          cacert
+          (writeTextDir "etc/nix/nix.conf" "experimental-features = nix-command flakes\n")
+        ];
 
-          ciJobImage = pkgs.dockerTools.buildLayeredImage {
-            name = "ci-job-image";
-            tag = "latest";
-            contents = ciJobContents;
-            config = {
-              Cmd = [ "/bin/sh" ];
-              Env = [
-                "PATH=${lib.makeBinPath ciJobContents}"
-                "SSL_CERT_FILE=${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt"
-                "NIX_SSL_CERT_FILE=${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt"
-                "NIX_REMOTE=daemon"
-              ];
-            };
+        ciJobImage = pkgs.dockerTools.buildLayeredImage {
+          name = "ci-job-image";
+          tag = "latest";
+          contents = ciJobContents;
+          config = {
+            Cmd = [ "/bin/sh" ];
+            Env = [
+              "PATH=${lib.makeBinPath ciJobContents}"
+              "SSL_CERT_FILE=${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt"
+              "NIX_SSL_CERT_FILE=${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt"
+              "NIX_REMOTE=daemon"
+            ];
           };
-        in
-        {
-          boot.kernelModules = [ "kvm-intel" ];
-          boot.extraModprobeConfig = "options kvm_intel nested=1";
+        };
+      in
+      {
+        boot.kernelModules = [ "kvm-intel" ];
+        boot.extraModprobeConfig = "options kvm_intel nested=1";
 
-          # volume-mounted into CI containers; must be in VM's store so
-          # image symlinks (/bin/node etc.) resolve through the mount
-          system.extraDependencies = ciJobContents;
+        # volume-mounted into CI containers; must be in VM's store so
+        # image symlinks (/bin/node etc.) resolve through the mount
+        system.extraDependencies = ciJobContents;
 
-          microvm.writableStoreOverlay = "/nix/.rw-store";
+        microvm.writableStoreOverlay = "/nix/.rw-store";
 
-          nix.settings = {
-            experimental-features = [
-              "nix-command"
-              "flakes"
+        nix.settings = {
+          experimental-features = [
+            "nix-command"
+            "flakes"
+          ];
+          max-jobs = "auto";
+        };
+
+        nix.gc = {
+          automatic = true;
+          dates = "daily";
+          options = "--delete-older-than 14d";
+        };
+        # nix.optimise.automatic = true; - doesn't work with microvm.writableStoreOverlay
+
+        services.journald.extraConfig = "ForwardToConsole=yes";
+
+        virtualisation.containerd.enable = true;
+        virtualisation.containerd.settings.plugins."io.containerd.snapshotter.v1.overlayfs".mount_options = [ "userxattr" ];
+
+        virtualisation.docker.enable = true;
+        virtualisation.docker.extraOptions = "--containerd /run/containerd/containerd.sock";
+        systemd.services.docker.wants = [ "containerd.service" ];
+        systemd.services.docker.after = [ "containerd.service" ];
+
+        systemd.services.load-ci-job-image = {
+          description = "Load the CI job Docker image";
+          wantedBy = [ "multi-user.target" ];
+          after = [ "docker.service" ];
+          requires = [ "docker.service" ];
+          before = [ "gitea-runner-${utils.escapeSystemdPath runnerInstanceName}.service" ];
+          serviceConfig = {
+            Type = "oneshot";
+            RemainAfterExit = true;
+            ExecStart = "${lib.getExe' pkgs.docker "docker"} load -i ${ciJobImage}";
+          };
+        };
+
+        services.gitea-actions-runner.instances.${runnerInstanceName} = {
+          enable = true;
+          name = runnerInstanceName;
+          url = "http://git:3000/";
+          tokenFile = "/run/ci-runner-secrets/token";
+          labels = [
+            "nix:docker://ci-job-image:latest"
+          ];
+          settings.container = {
+            options = "--device=/dev/kvm --volume=/nix/store:/nix/store:ro --volume=/nix/var/nix/daemon-socket:/nix/var/nix/daemon-socket";
+            valid_volumes = [
+              "/nix/store"
+              "/nix/var/nix/daemon-socket"
             ];
-            max-jobs = "auto";
-            substituters = [ "https://microvm.cachix.org" ];
-            trusted-public-keys = [ "microvm.cachix.org-1:oXnBc6hRE3eX5rSYdRyMYXnfzcCxC7yKPTbZXALsqys=" ];
-          };
-
-          nix.settings = {
-            min-free = 5 * 1024 * 1024 * 1024;
-            max-free = 10 * 1024 * 1024 * 1024;
-          };
-          # nix.optimise.automatic = true; - doesn't work with microvm.writableStoreOverlay
-
-          services.openssh = {
-            enable = true;
-            settings = {
-              PermitRootLogin = "yes";
-              PermitEmptyPasswords = "yes";
-            };
-          };
-          users.users.root.initialHashedPassword = "";
-          services.journald.extraConfig = "ForwardToConsole=yes";
-
-          virtualisation.containerd.enable = true;
-          virtualisation.containerd.settings.plugins."io.containerd.snapshotter.v1.overlayfs".mount_options =
-            [ "userxattr" ];
-
-          virtualisation.docker.enable = true;
-          virtualisation.docker.extraOptions = "--containerd /run/containerd/containerd.sock";
-          virtualisation.docker.daemon.settings.exec-opts = [ "native.cgroupdriver=cgroupfs" ];
-          systemd.services.docker.wants = [ "containerd.service" ];
-          systemd.services.docker.after = [ "containerd.service" ];
-
-          systemd.services.load-ci-job-image = {
-            description = "Load the CI job Docker image";
-            wantedBy = [ "multi-user.target" ];
-            after = [ "docker.service" ];
-            requires = [ "docker.service" ];
-            before = [ "gitea-runner-${utils.escapeSystemdPath runnerInstanceName}.service" ];
-            serviceConfig = {
-              Type = "oneshot";
-              RemainAfterExit = true;
-              ExecStart = "${lib.getExe' pkgs.docker "docker"} load -i ${ciJobImage}";
-            };
-          };
-
-          services.gitea-actions-runner.instances.${runnerInstanceName} = {
-            enable = true;
-            name = runnerInstanceName;
-            url = "http://git:3000/";
-            tokenFile = "/run/ci-runner-secrets/token";
-            labels = [
-              "nix:docker://ci-job-image:latest"
-            ];
-            settings.container = {
-              options = "--device=/dev/kvm --volume=/nix/store:/nix/store:ro --volume=/nix/var/nix/daemon-socket:/nix/var/nix/daemon-socket";
-              valid_volumes = [
-                "/nix/store"
-                "/nix/var/nix/daemon-socket"
-              ];
-            };
           };
         };
-    }
-    // {
-      hostConfig = {
-        systemd.tmpfiles.rules = [
-          "d ${ciRunnerData}/nix-rw-store 0755 server server -"
-          "d ${ciRunnerData}/nix-db 0755 server server -"
-          "d ${ciRunnerData}/docker 0755 server server -"
-          "d ${ciRunnerData}/runner-state 0755 server server -"
-        ];
       };
-    };
+  };
 }

containers/server-n0/nginx.nix

@@ -210,6 +210,6 @@ let
     };
     inherit (setup) containerConfig;
   };
-  inherit (c) hostAddr;
+  hostAddr = c.hostAddr;
 in
 c

containers/server-n0/ssh.nix

@@ -61,16 +61,27 @@ let
       net ? { },
       resources ? { },
       traits ? [ ],
+      isolation ? { },
     }:
     mkContainer {
       inherit name;
       inherit net resources;
       svc.autoStart = true;
-      isolation.nixDaemon = nixDaemon;
+      isolation = { nixDaemon = nixDaemon; } // isolation;
       traits = [ sshTrait ] ++ traits;
       packages = with pkgs; [ tmux ] ++ packages;
       miscProperties = self._sshpiperRegister routingInfo;
     };
+
+  kvmTrait = {
+    containerConfig =
+      { pkgs, ... }:
+      {
+        users.users.runner.extraGroups = [ "wheel" ];
+        security.sudo.wheelNeedsPassword = false;
+        environment.systemPackages = [ pkgs.qemu_kvm ];
+      };
+  };
 in
 {
   ssh-admin = mkSsh {
@@ -121,6 +132,25 @@ in
       mem = "16G";
       cpu = 65;
     };
+    traits = [ kvmTrait ];
+    isolation.allowedDevices = [
+      {
+        node = "/dev/kvm";
+        modifier = "rw";
+      }
+      {
+        node = "/dev/vhost-net";
+        modifier = "rw";
+      }
+      {
+        node = "/dev/net/tun";
+        modifier = "rwm";
+      }
+    ];
+    isolation.additionalCapabilities = [
+      "CAP_NET_ADMIN"
+      "CAP_MKNOD"
+    ];
     routingInfo = [
       {
         username = "autumn";

dsl.nix

@@ -228,6 +228,17 @@ rec {
     : systemd-nspawn user namespacing; see `--private-users=` in
       systemd-nspawn(1). Bind mounts always go through idmapped `--bind`.
 
+    `isolation.allowedDevices`
+    : List of `{ node; modifier; }` host devices to grant the container's
+      cgroup access to; see `containers.<name>.allowedDevices` in the NixOS
+      manual. nspawn bind-mounts a handful of devices (`/dev/kvm`,
+      `/dev/net/tun`, ...) into the container itself once the cgroup allows it -
+      this doesn't need a matching `resources.fs` bind mount.
+
+    `isolation.additionalCapabilities`
+    : Extra Linux capabilities granted to the container; see
+      `containers.<name>.additionalCapabilities` in the NixOS manual.
+
     `miscProperties`
     : Arbitrary data attached to the result. Used for cross-container discovery
       via `collectContainers`.
@@ -272,6 +283,8 @@ rec {
       bindMounts = resources.fs or { };
       allowsNixDaemon = isolation.nixDaemon or false;
       privateUsers = isolation.privateUsers or "pick";
+      allowedDevices = isolation.allowedDevices or [ ];
+      additionalCapabilities = isolation.additionalCapabilities or [ ];
 
       allowInternet = hasInternetAccess access;
       allBindMounts = builtins.foldl' (acc: t: acc // (t.resources.fs or { })) { } traits // bindMounts;
@@ -368,7 +381,12 @@ rec {
       kind = "nspawn";
       miscProperties = flattenMiscProp self miscProperties;
       nixosContainer = {
-        inherit autoStart privateUsers;
+        inherit
+          autoStart
+          privateUsers
+          allowedDevices
+          additionalCapabilities
+          ;
         bindMounts = { };
         extraFlags = bindMountExtraFlags;
         privateNetwork = true;
@@ -554,10 +572,7 @@ rec {
               Gateway = hostAddr;
             };
             networkConfig.DNS = [ hostAddr ];
-            networkConfig.Domains = [
-              "~."
-              "containers"
-            ];
+            networkConfig.Domains = [ "~." "containers" ];
             linkConfig.RequiredForOnline = if allowInternet then "routable" else "degraded";
           };
           networking.enableIPv6 = false;

flake.nix

@@ -129,10 +129,11 @@
     {
       nixosConfigurations = lib.mapAttrs (_: host: host.hostCfg) allHosts;
 
-      inspect = lib.mapAttrs (
-        name: host:
-        pkgs.writeText "inspect-${name}.json" (builtins.toJSON (introspect.hostReport { inherit host; }))
-      ) allHosts;
+      inspect = lib.mapAttrs
+        (name: host:
+          pkgs.writeText "inspect-${name}.json"
+            (builtins.toJSON (introspect.hostReport { inherit host; })))
+        allHosts;
 
       packages.${system} = customPkgs // {
         inherit ci;

hosts/example.nix

@@ -1,7 +1,7 @@
 _: {
   # New host: copy this file to hosts/<name>.nix. Replace fileSystems/boot
   # below with the real hardware (see hosts/server-n0.nix for a bigger
-  # example). Add a containers/<name>/ directory for its containers.
+  # example). Add a containers/<name>/ directory for its containers.  
 
   module =
     { lib, hostInfo, ... }:

tests/server-n0/integration.py

@@ -205,7 +205,12 @@ with subtest("(isolation): edges are one-way"):
     server.fail(ct_connect("git", ADDR["nginx"], 443, timeout=2))
 
 with subtest("(isolation): host access allowlist"):
-    server.succeed(ct_connect("overseer", HOST_ADDR["overseer"], HOST_EXPORTER_PORT))
+    server.succeed(
+        net_cmd(
+            "overseer",
+            f"{CURL} -sf --max-time 5 http://{HOST_ADDR['overseer']}:{HOST_EXPORTER_PORT}/metrics >&2",
+        )
+    )
     for port in (HOST_EXPORTER_PORT, HOST_CADVISOR_PORT):
         server.fail(ct_connect("git", HOST_ADDR["git"], port, timeout=2))
         server.fail(ct_connect("git", HOST_ADDR["overseer"], port, timeout=2))