Use Tart for Linux too instead of using Lima

.github/workflows/build.yml

@@ -27,23 +27,23 @@ jobs:
       - uses: actions/checkout@v6
       - run: nix build --print-build-logs .#homeConfigurations.samueles.activationPackage
 
-  hm-docker-x86:
+  hm-sandbox-amd64:
     runs-on: ubuntu-24.04
     steps:
       - uses: cachix/install-nix-action@v31
       - uses: actions/checkout@v6
       - run: nix build --print-build-logs .#homeConfigurations.agent-amd64.activationPackage
 
-  hm-docker-arm:
+  hm-ubuntu:
     runs-on: ubuntu-24.04-arm
     steps:
       - uses: cachix/install-nix-action@v31
       - uses: actions/checkout@v6
-      - run: nix build --print-build-logs .#homeConfigurations.agent-arm64.activationPackage
+      - run: nix build --print-build-logs .#homeConfigurations."admin@ubuntu".activationPackage
 
-  hm-tart:
+  hm-tahoe-vanilla:
     runs-on: macos-26
     steps:
       - uses: cachix/install-nix-action@v31
       - uses: actions/checkout@v6
-      - run: nix build --print-build-logs .#homeConfigurations.admin.activationPackage
+      - run: nix build --print-build-logs .#homeConfigurations."admin@tahoe-vanilla".activationPackage

.github/workflows/update.yml

@@ -55,7 +55,7 @@ jobs:
           name: flake.lock
       - run: nix build --print-build-logs .#homeConfigurations.samueles.activationPackage
 
-  hm-docker-x86:
+  hm-sandbox-amd64:
     needs: lock
     runs-on: ubuntu-24.04
     steps:
@@ -66,7 +66,7 @@ jobs:
           name: flake.lock
       - run: nix build --print-build-logs .#homeConfigurations.agent-amd64.activationPackage
 
-  hm-docker-arm:
+  hm-ubuntu:
     needs: lock
     runs-on: ubuntu-24.04-arm
     steps:
@@ -75,9 +75,9 @@ jobs:
       - uses: actions/download-artifact@v8
         with:
           name: flake.lock
-      - run: nix build --print-build-logs .#homeConfigurations.agent-arm64.activationPackage
+      - run: nix build --print-build-logs .#homeConfigurations."admin@ubuntu".activationPackage
 
-  hm-tart:
+  hm-tahoe-vanilla:
     needs: lock
     runs-on: macos-26
     steps:
@@ -86,17 +86,17 @@ jobs:
       - uses: actions/download-artifact@v8
         with:
           name: flake.lock
-      - run: nix build --print-build-logs .#homeConfigurations.admin.activationPackage
+      - run: nix build --print-build-logs .#homeConfigurations."admin@tahoe-vanilla".activationPackage
 
   pr:
     needs:
       - lock
       - nixos
       - hm-nixos
       - hm-macos
-      - hm-docker-x86
-      - hm-docker-arm
-      - hm-tart
+      - hm-sandbox-amd64
+      - hm-ubuntu
+      - hm-tahoe-vanilla
     runs-on: ubuntu-24.04
     steps:
       - uses: actions/checkout@v6

README.md

@@ -49,20 +49,9 @@ ln -s ~/github/samestep/env ~/.config/home-manager
 nix run ~/github/samestep/env#home-manager switch
 ```
 
-## Docker ([x86](docker-x86) and [ARM](docker-arm))
+## [libvirt](sandbox-amd64)
 
-This repo also contains dedicated Home Manager configs for use in an Ubuntu Docker container; for instance:
-
-```sh
-docker build . -t agent
-docker create agent sleep infinity
-```
-
-Then in VS Code, start the container and [attach to it](https://code.visualstudio.com/docs/devcontainers/attach-container).
-
-## [libvirt](docker-x86)
-
-The Docker configs can also be used for virtual machines. First make sure you have [virt-manager](https://virt-manager.org/), virt-viewer, and the [libvirt NSS module](https://libvirt.org/nss.html) installed, as they are in this repo's NixOS config. Then make sure you've started the `default` network:
+This config can also be used for x86 Linux virtual machines on Linux. First make sure you have [virt-manager](https://virt-manager.org/), virt-viewer, and the [libvirt NSS module](https://libvirt.org/nss.html) installed, as they are in this repo's NixOS config. Then make sure you've started the `default` network:
 
 ```sh
 virsh -c qemu:///system net-start default
@@ -176,41 +165,42 @@ And run this repo's script to generate `~/.ssh/tailnet`:
 tailnet
 ```
 
-## [Lima](docker-arm)
+## [Tart (Linux)](ubuntu)
 
-Similarly, the ARM Linux config can be used for a Linux virtual machine on macOS, via [Lima](https://lima-vm.io/) which comes with the host-side macOS config in this repo. First create the VM:
+This config can be used for ARM Linux virtual machines on macOS, via [Tart](https://tart.run/) which comes with the host-side macOS config in this repo. First, download an Ubuntu image:
 
-- The username and home directory location must be set to match what this Home Manager config expects.
-- Lima mounts the host-side home directory to the same path in the VM by default, so we disable that for security purposes.
-- By default Lima only gives the VM [user-mode networking](https://lima-vm.io/docs/config/network/user-v2/) (a userspace TCP/IP stack on the host), and SSH reaches the VM via a port forward through that stack, which adds enough per-packet latency to make interactive SSH typing lag. We add a [`vzNAT`](https://lima-vm.io/docs/config/network/vmnet/) interface so the VM also gets a real IP on Apple's `vmnet` network (the same `192.168.64.0/24` network, and mechanism, that Tart uses), reachable directly from the host. SSH straight to that IP to get the low-latency path. This requires `vmType: vz`, which is the default on Apple Silicon.
-- Nested virtualization is necessary for KVM to be available inside the VM.
+```sh
+tart clone ghcr.io/cirruslabs/ubuntu:latest ubuntu
+```
+
+By default, Tart doesn't give the VM all CPU cores, and only gives 8 GiB of RAM and 50 GB of disk space, so adjust those as appropriate:
 
 ```sh
-limactl start --name sandbox-arm64 --cpus 18 --memory 32 --disk 2000 --set '.user.name = "agent-arm64" | .user.home = "/home/agent-arm64" | .mounts = [] | .networks = [{"vzNAT": true}] | .nestedVirtualization = true' template:ubuntu
+tart set ubuntu --cpu 18 --memory 32768 --disk-size 2000
 ```
 
-Then configure it to start automatically in the background:
+Start up the VM:
 
 ```sh
-limactl autostart enable sandbox-arm64
+tart run --no-graphics ubuntu
 ```
 
-Enable Lima's SSH setup:
+Leave that running and, in a different terminal, give the VM your public SSH key give the VM your public SSH key so you don't need to type the password each time you connect:
 
 ```sh
-echo 'Include ~/.lima/*/ssh.config' >> ~/.ssh/config
+ssh-copy-id admin@$(tart ip ubuntu)
 ```
 
-Then SSH into the new VM. The `lima-sandbox-arm64` alias enabled by the previous command is fine for things like Git remotes, but laggy for interactive SSH, so use the following command instead:
+While adding the SSH key, you will need to type the password, which is `admin`. Then SSH into the VM:
 
 ```sh
-ssh -i ~/.lima/_config/user agent-arm64@lima-sandbox-arm64.local
+ssh admin@$(tart ip ubuntu)
 ```
 
-That command will start squawking after a reboot unless you run the following in the VM:
+Avoid ten-second hangs by enabling Ubuntu to resolve the local hostname:
 
 ```sh
-echo 'ssh_deletekeys: false' | sudo tee /etc/cloud/cloud.cfg.d/99-keep-ssh-host-keys.cfg
+echo "127.0.1.1 $(hostname)" | sudo tee -a /etc/hosts
 ```
 
 Next, install Nix:
@@ -219,7 +209,13 @@ Next, install Nix:
 sh <(curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install) --daemon
 ```
 
-Clone this repo:
+Enable [flakes][]:
+
+```sh
+echo 'experimental-features = nix-command flakes' | sudo tee -a /etc/nix/nix.conf
+```
+
+After installing Nix you'll need to log back out and back in. Then clone this repo:
 
 ```sh
 git clone https://github.com/samestep/env.git ~/github/samestep/env
@@ -228,7 +224,7 @@ git clone https://github.com/samestep/env.git ~/github/samestep/env
 Make a symlink for Home Manager:
 
 ```sh
-ln -fsT ~/github/samestep/env ~/.config/home-manager
+mkdir -p ~/.config && ln -fsT ~/github/samestep/env ~/.config/home-manager
 ```
 
 And activate the config:
@@ -246,7 +242,7 @@ curl -fsSL https://tailscale.com/install.sh | sh
 Connect to the tailnet:
 
 ```sh
-sudo tailscale up --ssh --hostname=sandbox-arm64
+sudo tailscale up --ssh --hostname=ubuntu
 ```
 
 And run this repo's script to generate `~/.ssh/tailnet`:
@@ -255,15 +251,15 @@ And run this repo's script to generate `~/.ssh/tailnet`:
 tailnet
 ```
 
-## [Tart](tart)
+## [Tart (macOS)](tahoe-vanilla)
 
-This config can be used for macOS VMs created with [Tart](https://tart.run/), which comes with the host-side macOS config in this repo. First, download a macOS image:
+This config can be used for macOS VMs, again using [Tart](https://tart.run/). First, download a macOS image:
 
 ```sh
 tart clone ghcr.io/cirruslabs/macos-tahoe-vanilla:latest tahoe-vanilla
 ```
 
-By default, Tart doesn't give the VM all CPU cores, and only gives 8 GiB of RAM and 50 GB of disk space, so adjust those as appropriate:
+Expand the provided CPU cores, RAM, and disk space:
 
 ```sh
 tart set tahoe-vanilla --cpu 18 --memory 16384 --disk-size 1000
@@ -317,13 +313,13 @@ Now shut down the VM again and reboot it once more, this time without graphics:
 tart run --no-graphics tahoe-vanilla
 ```
 
-Leave that running and, in a different terminal, give the VM your public SSH key give the VM your public SSH key so you don't need to type the password each time you connect:
+In a different terminal, give the VM your public SSH key, using the password `admin`:
 
 ```sh
 ssh-copy-id admin@$(tart ip tahoe-vanilla)
 ```
 
-While adding the SSH key, you will need to type the password, which is `admin`. Then SSH into the VM:
+Then SSH into the VM:
 
 ```sh
 ssh admin@$(tart ip tahoe-vanilla)

agent.md

@@ -37,7 +37,7 @@ ssh sandbox-amd64
 For the `aarch64-linux` VM:
 
 ```sh
-ssh sandbox-arm64
+ssh ubuntu
 ```
 
 For the `aarch64-darwin` VM:

bin/tailnet.py

@@ -3,7 +3,7 @@
 import subprocess
 from pathlib import Path
 
-HOSTS = ["sandbox-amd64", "sandbox-arm64", "tahoe-vanilla"]
+HOSTS = ["sandbox-amd64", "ubuntu", "tahoe-vanilla"]
 
 
 def main():

flake.nix

@@ -109,21 +109,6 @@
                 commaOverlay
                 npc.overlays.default
                 moss.overlays.default
-                (final: prev: {
-                  lima =
-                    assert final.lib.assertMsg (final.lib.versionOlder prev.lima.version "2.2.0")
-                      "Nixpkgs now ships Lima ${prev.lima.version} (>= 2.2.0); check if this fix is merged: https://github.com/lima-vm/lima/pull/5088";
-                    prev.lima.overrideAttrs (old: {
-                      version = "2.2.0-unstable-2026-07-02";
-                      src = final.fetchFromGitHub {
-                        owner = "resker";
-                        repo = "lima";
-                        rev = "f14b343a14f38490a76b9bac144fce1a3cf43d0b";
-                        hash = "sha256-eyvz7XbZKUVQZdSVmDmYlHQSCKFE23OeIH4N4hNDg3M=";
-                      };
-                      vendorHash = "sha256-nwNDuE76fVncegDKI/Fztpc30NX8/shNbSfzkrwTPDk=";
-                    });
-                })
               ];
             };
             modules = [
@@ -148,10 +133,10 @@
               nix-index-database.homeModules.default
               ./modules/base.nix
               ./modules/yolo.nix
-              ./docker-x86/home-manager/home.nix
+              ./sandbox-amd64/home-manager/home.nix
             ];
           };
-          "agent-arm64" = home-manager.lib.homeManagerConfiguration {
+          "admin@ubuntu" = home-manager.lib.homeManagerConfiguration {
             pkgs = import nixpkgs {
               system = "aarch64-linux";
               overlays = [
@@ -164,10 +149,10 @@
               nix-index-database.homeModules.default
               ./modules/base.nix
               ./modules/yolo.nix
-              ./docker-arm/home-manager/home.nix
+              ./ubuntu/home-manager/home.nix
             ];
           };
-          "admin" = home-manager.lib.homeManagerConfiguration {
+          "admin@tahoe-vanilla" = home-manager.lib.homeManagerConfiguration {
             pkgs = import nixpkgs {
               system = "aarch64-darwin";
               overlays = [
@@ -180,7 +165,7 @@
               nix-index-database.homeModules.default
               ./modules/base.nix
               ./modules/yolo.nix
-              ./tart/home-manager/home.nix
+              ./tahoe-vanilla/home-manager/home.nix
             ];
           };
         };

macos/home-manager/home.nix

@@ -18,7 +18,6 @@
 
     packages = [
       pkgs.gh
-      pkgs.lima
       pkgs.tart
     ];
 

modules/vscode.nix

@@ -17,12 +17,8 @@
         vscode.llvm-vs-code-extensions.vscode-clangd
         vscode.mkhl.direnv
         vscode.moss-lang.moss-vscode
-        vscode.ms-azuretools.vscode-containers
-        vscode.ms-azuretools.vscode-docker
         vscode.ms-python.python
         vscode.ms-python.vscode-pylance
-        vscode.ms-vscode-remote.remote-containers
-        vscode.ms-vscode-remote.remote-ssh
         vscode.ms-vscode.cmake-tools
         vscode.myriad-dreamin.tinymist
         vscode.ocamllabs.ocaml-platform

docker-x86/home-manager/home.nix → sandbox-amd64/home-manager/home.nix

@@ -1,7 +1,7 @@
 { ... }:
 {
   home = {
-    # # https://nix-community.github.io/home-manager/release-notes.xhtml
+    # https://nix-community.github.io/home-manager/release-notes.xhtml
     stateVersion = "25.11";
 
     username = "agent-amd64";

ssh/config

@@ -3,8 +3,8 @@ Include tailnet
 Host sandbox-amd64
   User agent-amd64
 
-Host sandbox-arm64
-  User agent-arm64
+Host ubuntu
+  User ubuntu
 
 Host tahoe-vanilla
   User admin

ubuntu/home-manager/home.nix

@@ -0,0 +1,12 @@
+{ ... }:
+{
+  home = {
+    # https://nix-community.github.io/home-manager/release-notes.xhtml
+    stateVersion = "26.05";
+
+    username = "admin";
+    homeDirectory = "/home/admin";
+  };
+
+  programs.bash.enable = true; # Necessary for aliases and Starship to work.
+}