0491fc43f2
Trues the runbook up to reality: guest GL stays software (llvmpipe) under Xvfb by deliberate choice (NVIDIA headless GL would need a different streaming architecture), the GPU slice costs ~100MiB VRAM only while awake, and the awake steady-state is ~0.5-1.3 cores / ~5Gi with scale-to-zero covering idle.
100 lines
4.7 KiB
Markdown
100 lines
4.7 KiB
Markdown
# android-emulator — shared in-cluster Android testing instance
|
||
|
||
Android 16 (API 36, `google_apis/x86_64`) emulator running under KVM in the
|
||
cluster, so agents can natively test app/PWA changes before shipping (first
|
||
tenant: tripit). Decision record: `docs/adr/0001-android-emulator-in-cluster.md`.
|
||
|
||
## On-demand lifecycle (since 2026-06-12)
|
||
|
||
The emulator **scales to zero when idle** (no adb/VNC connections for ~1h,
|
||
checked by the `android-emulator-idle-sleeper` CronJob) and **wakes on
|
||
visit**: the wake gate owns `/` on both hostnames. Warm boot is ~90s.
|
||
|
||
- Humans: open https://android-emulator.viktorbarzin.me — it wakes the
|
||
emulator if needed, shows a self-refreshing boot page, then hands over to
|
||
the noVNC screen.
|
||
- Agents (before adb): wake + poll, then connect:
|
||
|
||
curl -ks --resolve android-emulator.viktorbarzin.lan:443:10.0.20.203 https://android-emulator.viktorbarzin.lan/wake
|
||
until curl -ks --resolve android-emulator.viktorbarzin.lan:443:10.0.20.203 https://android-emulator.viktorbarzin.lan/status | grep -q '"ready": 1'; do sleep 5; done
|
||
adb connect 10.0.20.200:5555
|
||
|
||
## Endpoints
|
||
|
||
| What | Where |
|
||
|---|---|
|
||
| adb | `adb connect 10.0.20.200:5555` (LAN only; adb is unauthenticated — never expose publicly) |
|
||
| Screen (noVNC) | <https://android-emulator.viktorbarzin.lan/vnc.html> (LAN only) |
|
||
|
||
## Agent quickstart (from a devvm)
|
||
|
||
```bash
|
||
# one-time: user-local platform-tools
|
||
wget -qO /tmp/pt.zip https://dl.google.com/android/repository/platform-tools-latest-linux.zip
|
||
unzip -q /tmp/pt.zip -d ~/android-sdk # → ~/android-sdk/platform-tools/adb
|
||
|
||
adb="$HOME/android-sdk/platform-tools/adb"
|
||
$adb connect 10.0.20.200:5555
|
||
$adb -s 10.0.20.200:5555 install app-debug.apk # install an APK
|
||
$adb -s 10.0.20.200:5555 shell am start -a android.intent.action.VIEW -d https://tripit.viktorbarzin.me # open a URL
|
||
$adb -s 10.0.20.200:5555 shell input tap 540 1200 # drive the UI
|
||
$adb -s 10.0.20.200:5555 exec-out screencap -p > /tmp/screen.png # screenshot
|
||
```
|
||
|
||
The emulator is a single shared instance — `adb shell pm list packages`,
|
||
uninstall your test app when done, and presence-claim
|
||
(`presence claim service:android-emulator`) for long destructive sessions
|
||
(wipes, system-image changes).
|
||
|
||
## How it works
|
||
|
||
- The container image (built from `docker/`) holds only JDK 17, cmdline-tools,
|
||
emulator native libs, Xvfb/x11vnc/noVNC and socat — ~1GB.
|
||
- The SDK proper (platform-tools, emulator, system image, AVD, snapshots)
|
||
lives on the `android-emulator-sdk` PVC (`proxmox-lvm`); the entrypoint
|
||
installs it idempotently. **First boot downloads ~2.5GB (≈9GB unpacked on the PVC) and takes ~15 min**
|
||
(startup probe allows 30); subsequent restarts boot in ~1–2 min.
|
||
- The emulator runs on the GPU node (k8s-node1) with a T4 time-slice
|
||
(qemu holds ~100 MiB VRAM while awake; scale-to-zero keeps it transient).
|
||
Guest GL is deliberately SOFTWARE (llvmpipe): rendering into Xvfb pins GL
|
||
to the X stack, and true NVIDIA headless GL would need -no-window plus the
|
||
emulator's own streaming instead of x11vnc — not worth it at the measured
|
||
CPU numbers below.
|
||
|
||
## Rebuilding the image (rare — tool/library bumps only)
|
||
|
||
```bash
|
||
cd stacks/android-emulator/docker
|
||
docker build -t forgejo.viktorbarzin.me/viktor/android-emulator:<new-tag> .
|
||
docker push forgejo.viktorbarzin.me/viktor/android-emulator:<new-tag>
|
||
# then bump var.image_tag default in variables.tf and land via CI
|
||
```
|
||
|
||
Built manually from a devvm on purpose: it changes rarely, and a one-off push
|
||
doesn't warrant CI plumbing (the off-infra-CI rule targets *repeated* build IO).
|
||
|
||
## Troubleshooting
|
||
|
||
- Pod CrashLoops with `FATAL: /dev/kvm not present` → node lost the device or
|
||
the privileged/Kyverno exclude regressed (`android-emulator` must be in
|
||
`security_policy_exclude_namespaces`, stacks/kyverno).
|
||
- Wedged Android (won't boot, storage full) → delete the PVC + pod: next boot
|
||
re-downloads cleanly. Snapshots/AVD state are disposable by design.
|
||
- Different API level: set `API_LEVEL` env on the deployment (entrypoint
|
||
installs that system image on the same PVC) or recreate the AVD.
|
||
|
||
## Resource profile (measured 2026-06-12, v6 on node1)
|
||
|
||
- **Asleep (scaled to zero)**: nothing — the gate (~10m CPU/13Mi) is the only
|
||
standing cost.
|
||
- **Awake**: settles to **~0.5–1.3 cores** with a static screen (on or off),
|
||
~4.8–5.2 Gi memory (limit 8 Gi, requests 3 Gi), ~100 MiB T4 VRAM. Boot
|
||
bursts 5–9 cores for the first few minutes (dex2oat etc.).
|
||
- **Disk**: ~7 G of the 30 Gi PVC.
|
||
- Etiquette still applies for long sessions with animated content:
|
||
`adb -s 10.0.20.200:5555 shell input keyevent KEYCODE_SLEEP` when done.
|
||
|
||
## Remote access
|
||
|
||
https://android-emulator.viktorbarzin.me (Cloudflare-proxied, Authentik-gated)
|
||
serves the same noVNC screen for off-LAN use. adb stays LAN-only by design.
|