diff --git a/.github/workflows/diff-pr.yml b/.github/workflows/diff-pr.yml
index 7ba4bd7..17b0abf 100644
--- a/.github/workflows/diff-pr.yml
+++ b/.github/workflows/diff-pr.yml
@@ -13,26 +13,21 @@ concurrency:
 
 jobs:
   dix:
-    runs-on: ubuntu-latest
+    runs-on: nix
     steps:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - uses: cachix/install-nix-action@v31
-        with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-
       - name: worktree base for diff
         run: git worktree add "$RUNNER_TEMP/base" "${{ github.event.pull_request.base.sha }}"
 
       - name: build closures and render diff
         run: |
-          nix run .#ci -- diff "$RUNNER_TEMP/base" . \
+          nix run -L .#ci -- diff "$RUNNER_TEMP/base" . \
             "### System closure diff vs \`${{ github.event.pull_request.base.ref }}\`" \
             > "$RUNNER_TEMP/comment.md"
-          nix run .#ci -- inspect-diff "$RUNNER_TEMP/base" . \
+          nix run -L .#ci -- inspect-diff "$RUNNER_TEMP/base" . \
             "### Inspection diff vs \`${{ github.event.pull_request.base.ref }}\`" \
             >> "$RUNNER_TEMP/comment.md"
 
@@ -42,4 +37,4 @@ jobs:
           API: ${{ github.api_url }}
           REPO: ${{ github.repository }}
           PR: ${{ github.event.pull_request.number }}
-        run: nix run .#ci -- post-comment "<!-- dix-diff -->" "$RUNNER_TEMP/comment.md"
+        run: nix run -L .#ci -- post-comment "<!-- dix-diff -->" "$RUNNER_TEMP/comment.md"
diff --git a/.github/workflows/diff-tag.yml b/.github/workflows/diff-tag.yml
index 8224366..381814d 100644
--- a/.github/workflows/diff-tag.yml
+++ b/.github/workflows/diff-tag.yml
@@ -9,17 +9,12 @@ permissions:
 
 jobs:
   dix:
-    runs-on: ubuntu-latest
+    runs-on: nix
     steps:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - uses: cachix/install-nix-action@v31
-        with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-
       - name: diff latest tag against HEAD
         run: |
           tag=$(git tag --sort=-creatordate | head -n1)
@@ -30,8 +25,8 @@ jobs:
           git worktree add "$RUNNER_TEMP/old" "$tag"
           head=$(git rev-parse --short HEAD)
           {
-            nix run .#ci -- diff "$RUNNER_TEMP/old" . \
+            nix run -L .#ci -- diff "$RUNNER_TEMP/old" . \
               "# System closure diff: \`$tag\` -> \`$head\`"
-            nix run .#ci -- inspect-diff "$RUNNER_TEMP/old" . \
+            nix run -L .#ci -- inspect-diff "$RUNNER_TEMP/old" . \
               "# Inspection diff: \`$tag\` -> \`$head\`"
           } | tee -a "$GITHUB_STEP_SUMMARY"
diff --git a/.github/workflows/flake-check.yml b/.github/workflows/flake-check.yml
index 452cfe6..9e6642d 100644
--- a/.github/workflows/flake-check.yml
+++ b/.github/workflows/flake-check.yml
@@ -14,13 +14,8 @@ concurrency:
 
 jobs:
   flake-check:
-    runs-on: ubuntu-latest
+    runs-on: nix
     steps:
       - uses: actions/checkout@v4
 
-      - uses: cachix/install-nix-action@v31
-        with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-
       - run: nix flake check -L
diff --git a/.github/workflows/flake-update.yml b/.github/workflows/flake-update.yml
index 2e57a9e..27ec96d 100644
--- a/.github/workflows/flake-update.yml
+++ b/.github/workflows/flake-update.yml
@@ -11,16 +11,11 @@ permissions:
 
 jobs:
   update:
-    runs-on: ubuntu-latest
+    runs-on: nix
     steps:
       - uses: actions/checkout@v4
 
-      - uses: cachix/install-nix-action@v31
-        with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-
-      - run: nix flake update
+      - run: nix flake update -L
 
       - name: open/update PR
         env:
@@ -29,5 +24,5 @@ jobs:
           REPO: ${{ github.repository }}
         run: |
           printf 'Automated `nix flake update`.\n' > "$RUNNER_TEMP/body.md"
-          nix run .#ci -- open-pr \
+          nix run -L .#ci -- open-pr \
             flake-update "$GITHUB_REF_NAME" "flake.lock: update inputs" "$RUNNER_TEMP/body.md" automated
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 89a6d6f..bb0b54c 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -15,15 +15,10 @@ concurrency:
 
 jobs:
   lint:
-    runs-on: ubuntu-latest
+    runs-on: nix
     steps:
       - uses: actions/checkout@v4
 
-      - uses: cachix/install-nix-action@v31
-        with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-
       - name: pick reporter
         run: |
           if [ "${{ github.event_name }}" = pull_request ]; then
@@ -33,9 +28,9 @@ jobs:
           fi
 
       - name: run linters
-        run: nix run .#ci -- lint . "$RUNNER_TEMP/findings"
+        run: nix run -L .#ci -- lint . "$RUNNER_TEMP/findings"
 
       - name: report findings
         env:
           REVIEWDOG_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: nix run .#ci -- lint-report "$REPORTER" "$RUNNER_TEMP/findings"
+        run: nix run -L .#ci -- lint-report "$REPORTER" "$RUNNER_TEMP/findings"
diff --git a/.github/workflows/vulnix.yml b/.github/workflows/vulnix.yml
index aa7e347..13a5440 100644
--- a/.github/workflows/vulnix.yml
+++ b/.github/workflows/vulnix.yml
@@ -11,18 +11,13 @@ permissions:
 
 jobs:
   scan:
-    runs-on: ubuntu-latest
+    runs-on: nix
     steps:
       - uses: actions/checkout@v4
 
-      - uses: cachix/install-nix-action@v31
-        with:
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-
       - name: scan host closures
         id: scan
-        run: echo "count=$(nix run .#ci -- vulnix . "$RUNNER_TEMP/issue.md")" >> "$GITHUB_OUTPUT"
+        run: echo "count=$(nix run -L .#ci -- vulnix . "$RUNNER_TEMP/issue.md")" >> "$GITHUB_OUTPUT"
 
       - name: file/update issue
         if: steps.scan.outputs.count != '0'
@@ -30,7 +25,7 @@ jobs:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           API: ${{ github.api_url }}
           REPO: ${{ github.repository }}
-        run: nix run .#ci -- upsert-issue vulnix "vulnix: known vulnerabilities in system closure" "$RUNNER_TEMP/issue.md"
+        run: nix run -L .#ci -- upsert-issue vulnix "vulnix: known vulnerabilities in system closure" "$RUNNER_TEMP/issue.md"
 
       - name: close resolved issue
         if: steps.scan.outputs.count == '0'
@@ -38,4 +33,4 @@ jobs:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           API: ${{ github.api_url }}
           REPO: ${{ github.repository }}
-        run: nix run .#ci -- close-issue vulnix
+        run: nix run -L .#ci -- close-issue vulnix
diff --git a/ci.py b/ci.py
index e4a3d57..56512ac 100644
--- a/ci.py
+++ b/ci.py
@@ -17,7 +17,7 @@ def run(*args, **kw):
 
 
 def nix(*args):
-    return run("nix", "--extra-experimental-features", "nix-command flakes", *args, check=True, capture_output=True).stdout
+    return run("nix", "--extra-experimental-features", "nix-command flakes", "-L", *args, check=True, stdout=subprocess.PIPE).stdout
 
 
 def git(*args, check=True):
diff --git a/containers/server-n0/git.nix b/containers/server-n0/git.nix
index f4510d7..b09a7c4 100644
--- a/containers/server-n0/git.nix
+++ b/containers/server-n0/git.nix
@@ -8,6 +8,9 @@ let
   inherit (dsl) mkContainer mkVm;
   inherit (hostInfo.paths) data secrets;
 
+  pubSshPort = 23;
+  intSshPort = 23 + 8000;
+
   ciRunnerData = "${data}/web/git-ci-runner";
   ciRunnerSecrets = "${secrets}/ci-runner";
 in
@@ -17,8 +20,8 @@ in
     net.access = [ { to = "@internet"; } ];
     net.forward.tcp = [
       {
-        host = 23;
-        container = 8023;
+        host = pubSshPort;
+        container = intSshPort;
       }
     ];
     svc.autoStart = true;
@@ -38,7 +41,8 @@ in
             ROOT_URL = "https://git.floweytf.com/";
             START_SSH_SERVER = true;
             BUILTIN_SSH_SERVER_USER = "git";
-            SSH_PORT = 8023;
+            SSH_PORT = pubSshPort;
+            SSH_LISTEN_PORT = intSshPort;
           };
           service.DISABLE_REGISTRATION = true;
         };
@@ -53,6 +57,7 @@ in
 
   ci-runner = mkVm {
     name = "ci-runner";
+    includedInTests = false;
     net.access = [
       {
         to = "git";
@@ -62,7 +67,7 @@ in
     ];
     svc.autoStart = true;
     resources.cpu = 4;
-    resources.mem = "8G";
+    resources.mem = "32G";
     resources.fs = [
       {
         proto = "virtiofs";
@@ -80,7 +85,7 @@ in
         proto = "virtiofs";
         tag = "runner-state";
         source = "${ciRunnerData}/runner-state";
-        mountPoint = "/var/lib/gitea-runner";
+        mountPoint = "/var/lib/private/gitea-runner";
       }
       {
         proto = "virtiofs";
@@ -100,20 +105,24 @@ in
       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")
+        ];
+
         ciJobImage = pkgs.dockerTools.buildLayeredImage {
           name = "ci-job-image";
           tag = "latest";
-          contents = with pkgs; [
-            bashInteractive
-            coreutils
-            gitMinimal
-            nixVersions.latest
-            nodejs
-            cacert
-          ];
+          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"
@@ -125,6 +134,10 @@ 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;
+
         microvm.writableStoreOverlay = "/nix/.rw-store";
 
         nix.settings = {
@@ -142,7 +155,15 @@ in
         };
         # 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";
diff --git a/dsl.nix b/dsl.nix
index 1c6dcf0..8eb4d81 100644
--- a/dsl.nix
+++ b/dsl.nix
@@ -571,6 +571,8 @@ rec {
               Destination = "0.0.0.0/0";
               Gateway = hostAddr;
             };
+            networkConfig.DNS = [ hostAddr ];
+            networkConfig.Domains = [ "~." "containers" ];
             linkConfig.RequiredForOnline = if allowInternet then "routable" else "degraded";
           };
           networking.enableIPv6 = false;