coder/desktop: KDE Plasma instead of XFCE

Add image/Dockerfile (published as
git.nic-oconnor.com/public/coder-desktop-kde:noble): enterprise-desktop
noble plus KDE Plasma and KasmVNC 1.5.0, baked in so starts skip apt.
It carries three fixes found testing in the cluster:

- kwin-x11 installed explicitly (only a Recommends; without it Plasma
  runs with no window manager),
- startkde -> startplasma-x11 symlink, since KasmVNC's -select-de kde
  checks for startkde and Plasma 5.20+ renamed it,
- KWin compositing off by default (no GPU; it only adds VNC lag).

The template now uses that image with desktop_environment = "kde" and
pulls Always, and drops the XFCE .xsessionrc seeding.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -97,7 +97,7 @@ Already have a clone? Just run it directly:
 
 Not run by `bootstrap.sh`:
 
-- `coder/desktop/` — Coder template for coder.nic-oconnor.com: an XFCE
+- `coder/desktop/` — Coder template for coder.nic-oconnor.com: a KDE Plasma
   desktop (KasmVNC) pod on the homelab cluster that applies this repo via the
   dotfiles module. Push with `coder templates push desktop -d coder/desktop`;
   see its README.

coder/desktop/README.md

@@ -1,7 +1,7 @@
 # coder/desktop — Coder desktop template
 
-A Coder template for <https://coder.nic-oconnor.com>: an XFCE desktop in the
+A Coder template for <https://coder.nic-oconnor.com>: a KDE Plasma desktop in
-browser (the [KasmVNC module](https://registry.coder.com/modules/coder/kasmvnc))
+the browser (the [KasmVNC module](https://registry.coder.com/modules/coder/kasmvnc))
 running as a pod on the homelab Kubernetes cluster, set up from this repo by the
 [dotfiles module](https://registry.coder.com/modules/coder/dotfiles).
 
@@ -15,14 +15,42 @@ coder templates push desktop -d coder/desktop -y
 The in-cluster provisioner uses the `coder` service account, whose workspace
 Role is bound in the `coder` namespace — which is where workspaces go.
 
+## The image
+
+`image/Dockerfile` builds `git.nic-oconnor.com/public/coder-desktop-kde:noble`:
+`codercom/enterprise-desktop:ubuntu-noble` plus KDE Plasma (with Dolphin,
+Konsole, Kate) and KasmVNC. Both are baked in because only `/home/coder` is
+persisted, so installing them at start time would cost minutes on every
+start. The package is public on Gitea, so the cluster pulls it without a
+secret. Rebuild after changing the Dockerfile:
+
+```sh
+docker build -t git.nic-oconnor.com/public/coder-desktop-kde:noble coder/desktop/image
+docker push git.nic-oconnor.com/public/coder-desktop-kde:noble
+```
+
+The pod pulls with `Always`, so workspaces pick the new image up on their
+next start.
+
+Workarounds the Dockerfile carries:
+
+- `kwin-x11` is installed explicitly. It is only a Recommends of
+  `kde-plasma-desktop`, and without it Plasma starts with no window manager.
+- `/usr/local/bin/startkde -> startplasma-x11`. KasmVNC's `-select-de kde`
+  (what the module runs) checks for `startkde`, which Plasma 5.20+ renamed,
+  and otherwise fails with "Desktop Environment not installed".
+- KWin compositing is off in `/etc/xdg/kwinrc`: there is no GPU, and
+  software compositing over VNC only adds lag. Turn it back on in System
+  Settings if you want it.
+
 ## What a workspace gets
 
-- `codercom/enterprise-desktop:ubuntu-noble`: XFCE, git, python3, and the
+- The image above, running as the `coder` user (uid 1000) with passwordless
-  `coder` user (uid 1000) with passwordless sudo.
+  sudo.
 - A PVC (`truenas-iscsi`, default 30 GiB) at `/home/coder`. Everything the
-  dotfiles install into `$HOME` survives stops; system packages (zsh, docker
+  dotfiles install into `$HOME` survives stops, and so do the Plasma settings.
-  CLI, KasmVNC) are reinstalled on each start because the root filesystem
+  System packages the dotfiles add (zsh, the docker CLI) are reinstalled on
-  is not persisted.
+  each start.
 - The KasmVNC app, path-based (`subdomain = false`) because the deployment has
   no wildcard access URL.
 - A "Dotfiles" startup script: clones this repo into
@@ -42,9 +70,9 @@ bootstrap still applies everything else; `secrets`, `mcp-config` and `hermes`
 are reported as not completed. Fix that later from a workspace terminal with
 `~/.config/coderv2/dotfiles/secrets/install.sh`, then refresh the dotfiles.
 
-## Why these pins
+## Why noble
 
-- `ubuntu-noble`, not `ubuntu`: the `ubuntu` tag is now 26.04 (resolute), and
+The `enterprise-desktop:ubuntu` tag is now 26.04 (resolute), and KasmVNC
-  KasmVNC publishes no resolute package, so the module's install 404s.
+publishes no resolute package. The image is pinned to noble with KasmVNC
-- `kasm_version = "1.5.0"`: the newest KasmVNC release, which has a noble
+1.5.0; revisit once KasmVNC ships a resolute `.deb`, and keep
-  build. Revisit both once KasmVNC ships a resolute `.deb`.
+`kasm_version` in `main.tf` in step with `KASMVNC_VERSION`.

coder/desktop/image/Dockerfile

@@ -0,0 +1,34 @@
+# coder/desktop/image — the workspace image: Coder's desktop base with KDE
+# Plasma and KasmVNC baked in, so a start does not spend minutes in apt (the
+# root filesystem is not persisted; only /home/coder is).
+#
+#   docker build -t git.nic-oconnor.com/public/coder-desktop-kde:noble coder/desktop/image
+#   docker push git.nic-oconnor.com/public/coder-desktop-kde:noble
+#
+# noble, not resolute: KasmVNC publishes no resolute package yet.
+FROM codercom/enterprise-desktop:ubuntu-noble
+
+ARG KASMVNC_VERSION=1.5.0
+
+USER root
+# kwin-x11 is only a Recommends of kde-plasma-desktop, so --no-install-recommends
+# drops it and Plasma comes up with no window manager (no title bars).
+RUN apt-get update \
+ && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
+      kde-plasma-desktop kwin-x11 dolphin konsole kate plasma-nm breeze-gtk-theme \
+      dbus-x11 libdatetime-perl \
+ && curl -fsSL -o /tmp/kasmvnc.deb \
+      "https://github.com/kasmtech/KasmVNC/releases/download/v${KASMVNC_VERSION}/kasmvncserver_noble_${KASMVNC_VERSION}_amd64.deb" \
+ && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends /tmp/kasmvnc.deb \
+ && rm -f /tmp/kasmvnc.deb /home/coder/.xsessionrc \
+ && rm -rf /var/lib/apt/lists/*
+
+# KasmVNC's `-select-de kde` (what the Coder kasmvnc module runs) looks for a
+# `startkde` binary, which Plasma 5.20+ renamed to startplasma-x11.
+RUN ln -s /usr/bin/startplasma-x11 /usr/local/bin/startkde
+
+# No GPU in the pod: software compositing over VNC only adds lag. Users can
+# still turn it on in System Settings (~/.config/kwinrc overrides this).
+RUN printf '[Compositing]\nEnabled=false\n' > /etc/xdg/kwinrc
+
+USER coder

coder/desktop/main.tf

@@ -1,4 +1,4 @@
-# coder/desktop — Coder template: an XFCE desktop in the browser (KasmVNC)
+# coder/desktop — Coder template: a KDE Plasma desktop in the browser (KasmVNC)
 # on the homelab Kubernetes cluster, set up from this dotfiles repo.
 #
 # Push it with:  coder templates push desktop -d coder/desktop
@@ -174,21 +174,14 @@ resource "coder_agent" "main" {
   arch = data.coder_provisioner.me.arch
   os   = "linux"
 
-  # The home PVC hides whatever the image put in /home/coder, so seed it on
+  # The home PVC hides whatever the image put in /home/coder, so seed it
-  # first start: the skel dotfiles, plus the image's .xsessionrc (XFCE session
+  # with the skel dotfiles on first start.
-  # env that KasmVNC's X session reads).
   startup_script = <<-EOT
     set -e
     if [ ! -f ~/.init_done ]; then
       cp -rT /etc/skel ~ || true
       touch ~/.init_done
     fi
-    if [ ! -f ~/.xsessionrc ]; then
-      printf '%s\n' \
-        'export GNOME_SHELL_SESSION_MODE=ubuntu' \
-        'export XDG_CURRENT_DESKTOP=xfce' \
-        'export XDG_SESSION_TYPE=x11' > ~/.xsessionrc
-    fi
   EOT
 
   env = merge({
@@ -235,9 +228,10 @@ module "dotfiles" {
   manual_update        = true
 }
 
-# XFCE is in the image; the module installs KasmVNC and serves it on :6800.
+# KDE Plasma and KasmVNC are baked into the image (image/Dockerfile), so the
-#   kasm_version: KasmVNC ships a .deb per Ubuntu codename, and the module's
+# module skips its install and just configures and starts KasmVNC on :6800.
-#     default (1.4.0) is older than we need; 1.5.0 has noble.
+#   kasm_version: only used if the image lacks KasmVNC; keep it in step with
+#     KASMVNC_VERSION in the Dockerfile.
 #   subdomain = false: the deployment has no wildcard access URL, so the app
 #     is served path-based under coder.nic-oconnor.com.
 module "kasmvnc" {
@@ -245,7 +239,7 @@ module "kasmvnc" {
   source              = "registry.coder.com/coder/kasmvnc/coder"
   version             = "1.3.0"
   agent_id            = coder_agent.main.id
-  desktop_environment = "xfce"
+  desktop_environment = "kde"
   kasm_version        = "1.5.0"
   subdomain           = false
 }
@@ -299,8 +293,9 @@ resource "kubernetes_deployment_v1" "main" {
       }
       spec {
         # Runs as the image's coder user (uid 1000), which has passwordless
-        # sudo. The KasmVNC module and the dotfiles modules (zsh, docker)
+        # sudo. The KasmVNC module needs it to write /etc/kasmvnc, and the
-        # need it for apt; the namespace enforces PSA baseline, which allows it.
+        # dotfiles modules (zsh, docker) for apt; the namespace enforces PSA
+        # baseline, which allows it.
         security_context {
           run_as_user     = 1000
           fs_group        = 1000
@@ -309,8 +304,8 @@ resource "kubernetes_deployment_v1" "main" {
 
         container {
           name              = "dev"
-          image             = "codercom/enterprise-desktop:ubuntu-noble"
+          image             = "git.nic-oconnor.com/public/coder-desktop-kde:noble"
-          image_pull_policy = "IfNotPresent"
+          image_pull_policy = "Always"
           command           = ["sh", "-c", coder_agent.main.init_script]
           env {
             name  = "CODER_AGENT_TOKEN"