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Ephemeral Sandbox Pod Scheduler

Browser IDE that provisions a real, isolated Kubernetes pod per project on demand. init-service seeds the project into S3/R2; orchestrator-simple creates a Deployment/Service/Ingress/NetworkPolicy via the k8s API; runner streams a live terminal (node-pty) and editor over Socket.IO; nginx-ingress routes each project by subdomain. An anonymous JWT + SQLite ownership record gates /project, /start, and the runner's socket connection so only the creator of a replId can reach it.

What this is

A browser-based code editor and terminal, like Session Multiplexer Code Shell, rebuilt so every project gets its own isolated compute instead of sharing one host. Opening a project schedules a dedicated Kubernetes pod just for it, with its own filesystem, CPU/memory limits, and a real shell, reachable at its own subdomain, and torn down independently of every other project.

How it works

  1. Auth bootstrap : on first load, the frontend calls POST /auth/session on init-service and caches the anonymous session token it gets back (see Auth & ownership). Every request below carries this token.
  2. Project creation : POST /project on init-service verifies the token, rejects an already-taken replId (409), copies a base template (node-js or python) from S3/R2 into code/<replId>, and records (replId, ownerId) in a shared SQLite table. This step only prepares storage; it does not start any compute.
  3. Pod scheduling : when a user opens a project, the frontend calls POST /start on orchestrator-simple with the replId. The orchestrator verifies the token, checks the caller owns this replId (403/404 otherwise), then reads a parameterized Kubernetes manifest (service.yaml), substitutes service_name → replId and owner_id_placeholder → the verified owner across every document, and creates each resource via the Kubernetes API (@kubernetes/client-node):
    • a Deployment running the runner image, with an init container that aws s3 cps that project's files from the bucket into a mounted emptyDir volume before the main container starts
    • a Service exposing the pod's port 3001 (WebSocket) and 3000 (the user's own running app)
    • an Ingress routing <replId>.<domain> (two configured hostnames) to those ports
    • a NetworkPolicy scoping that pod's ingress/egress (see Network policy)
  4. Editing & terminal : the frontend connects a Socket.IO client directly to ws://<replId>.<domain>, presenting its token in the handshake. The runner inside that specific pod identifies which project it's serving from the subdomain in the request's Host header (not a query param, since there's exactly one project per pod), and rejects the connection unless the token's owner matches the pod's own OWNER_ID. File read/write and terminal I/O work the same way as the single-host version, except everything happens inside /workspace (the volume the init container populated) rather than a shared local tmp/ folder.
  5. Live preview : the frontend's Output panel points its iframe at http://<replId>.<domain>, which the Ingress routes to the pod's port 3000. On boot, the runner also auto-detects the project type and runs its install+start command in the background (see Automatic run step), so this is usually already live; the user can still run their own commands manually in the terminal too.

Architecture

Frontend (Vite + React)
   │
   ├─ POST /project  ────────────▶  init-service  ──▶ copy base/<lang> → S3/R2: code/<replId>
   │                                  (:3001)
   │
   ├─ POST /start {replId} ──────▶  orchestrator-simple  ──▶ Kubernetes API
   │                                  (:3002)                    │
   │                                                              ├─ Deployment (runner + init container)
   │                                                              ├─ Service (:3001 ws, :3000 user app)
   │                                                              └─ Ingress (<replId>.<domain>)
   │
   └─ Socket.IO + iframe ────────▶  <replId>.<domain>  ──▶  nginx-ingress  ──▶  runner pod
                                                                                    │
                                                                              init container:
                                                                              aws s3 cp (S3/R2 → /workspace)
                                                                                    │
                                                                              node-pty (terminal)
                                                                              file read/write
                                                                              user's own process on :3000
  • One pod per project. Each replId gets its own Deployment, Service, and Ingress. Real isolation (separate filesystem, CPU/memory requests+limits) instead of every user sharing one backend process.
  • Subdomain-based routing, not path-based. Two ingress hosts are wired per project (<replId>.peetcode.com, <replId>.autogpt-cloud.com by default). Config-driven via WS_DOMAIN/APP_DOMAIN - see Configurable domains - not edited into service.yaml directly.
  • Storage is still the source of truth. Pods are disposable; nothing written outside /workspace survives a pod restart, and /workspace itself is only ever seeded once, at pod startup, by the init container.

Tech stack

Service Role Key dependencies
init-service Project creation (template → storage) Express, AWS SDK (S3), jsonwebtoken, better-sqlite3
orchestrator-simple Schedules per-project k8s resources, lifecycle + health monitoring Express, @kubernetes/client-node (incl. Metrics API), yaml, jsonwebtoken, better-sqlite3, axios
runner Per-pod backend: terminal + file sync Express, Socket.IO, node-pty, AWS SDK (S3), jsonwebtoken
frontend Editor UI, triggers /start, connects to the pod React, Vite, Monaco Editor, xterm.js
k8s/ Cluster-level ingress controller manifests nginx-ingress

Project structure

init-service/
  src/
    index.ts    # POST /project, POST /auth/session — copies base template to S3/R2
    aws.ts       # S3/R2 client + copy helpers
    auth.ts      # JWT sign/verify + requireAuth middleware
    db.ts        # SQLite ownership store (replId -> ownerId)
    rateLimit.ts # per-user token-bucket limiter on POST /project
  Dockerfile     # builds init-service for deployment (see "Deploying the schedulers")

orchestrator-simple/
  src/
    index.ts        # POST /start, POST /stop, GET /status, GET /projects/:replId/status
    auth.ts          # JWT verify + requireAuth middleware
    db.ts            # SQLite ownership store + lifecycle/health status, restart count
    stop.ts          # shared stop-with-final-sync logic, used by POST /stop and the reaper
    reaper.ts        # background loop: polls started projects' /health, auto-stops idle ones
    monitor.ts       # pod status (crash-loop/OOM) + resource usage via the k8s API/Metrics API
    healthMonitor.ts # background loop: marks projects unhealthy on crash-loop, fires alerts
    namespace.ts     # per-project namespace (sandbox-<replId>) create/delete helpers
    capacity.ts      # retry-with-backoff + Unschedulable-pod detection + error translation
    rateLimit.ts     # per-user token-bucket limiter on POST /start
  service.yaml   # parameterized manifest template (service_name / owner_id_placeholder / ws_domain_placeholder / app_domain_placeholder)
  Dockerfile     # builds orchestrator-simple for deployment (see "Deploying the schedulers")

runner/
  src/
    index.ts    # entrypoint — HTTP + WS server for a single pod; GET /health, POST /shutdown
    ws.ts        # Socket.IO handlers — replId derived from Host header, tracks last-activity
    auth.ts      # JWT verify (validates the socket handshake against OWNER_ID)
    autorun.ts   # detects project type in /workspace, auto-runs install+start on pod boot
    sync.ts      # recursively re-syncs /workspace to S3/R2 on /shutdown or SIGTERM
    pty.ts       # TerminalManager — same PTY-per-session model, scoped to one pod
    fs.ts        # local filesystem helpers (operates on /workspace)
    aws.ts       # S3/R2 helpers (saveToS3 on file updates)
  Dockerfile      # builds the runner image the orchestrator deploys per pod

frontend/
  src/
    lib/
      auth.ts        # bootstraps/caches the anonymous session token
      config.ts       # every deployment-configurable backend address (init-service, orchestrator, TLS)
    components/
      Landing.tsx     # create a project (calls init-service)
      CodingPage.tsx  # calls orchestrator /start, waits for pod, polls per-project health
      Output.tsx      # iframe at http://<replId>.<domain>

k8s/
  ingress-controller.yaml   # nginx-ingress-controller cluster setup
  create-secret.sh          # creates the sandbox-secrets k8s Secret from your shell env
  cluster-issuer.yaml       # cert-manager Let's Encrypt ClusterIssuer (DNS01)
  rbac.yaml                 # ServiceAccount/ClusterRole/ClusterRoleBinding for in-cluster orchestrator-simple
  scheduler-services.yaml   # optional: Deployments/Services/Ingress to run init-service + orchestrator-simple in-cluster
  wildcard-certificate.yaml # one wildcard cert covering both project domains

Getting started

Prerequisites

  • A Kubernetes cluster you have kubectl/API access to, with nginx-ingress installed (see k8s/ingress-controller.yaml)
  • A domain (or two) with wildcard DNS pointed at your ingress controller's external IP, so <anything>.yourdomain.com resolves
  • An S3-compatible bucket — AWS S3 or Cloudflare R2 — with base/node-js and base/python template folders pre-seeded
  • A container registry to push the runner image to (the sample manifest references 100xdevs/runner:latest — replace with your own)
  • Node.js 18+
  • Optional but recommended: metrics-server installed in your cluster, for /status's per-pod CPU/memory numbers. Without it, resource usage just reports as null - everything else still works.

1. Build and push the runner image

cd runner
docker build -t <your-registry>/runner:latest .
docker push <your-registry>/runner:latest

Update the image: field in orchestrator-simple/service.yaml to match.

2. Configure the manifest template

Edit orchestrator-simple/service.yaml:

  • set your registry image
  • replace the ingress-controller namespace label in the NetworkPolicy doc if yours isn't ingress-nginx, and fill in your cluster's pod/service CIDRs (see comments in the file, and Network policy below)
  • S3_BUCKET / S3_ENDPOINT on the runner container are literal placeholder values in the template — edit them directly, same as the image above

The Ingress hostnames are not edited directly anymore - ws_domain_placeholder/app_domain_placeholder are substituted at /start time from orchestrator-simple's WS_DOMAIN/APP_DOMAIN env vars (step 5), the same mechanism already used for service_name. This is what makes the domains config-driven instead of baked into the committed template - see Configurable domains.

RBAC note: since each project now gets its own namespace (see Namespace isolation), the credentials orchestrator-simple runs with need cluster-scoped permissions - not just a Role in one namespace - to create/delete Namespaces and to create/delete Deployments/Services/Ingresses/NetworkPolicies inside them. A kubectl admin kubeconfig already has this; a locked-down in-cluster ServiceAccount needs a ClusterRole/ClusterRoleBinding covering namespaces (create, delete, get) plus the existing resource kinds at cluster scope.

3. Create the credentials Secret

Real credentials no longer live in service.yaml — they're read from a Kubernetes Secret at pod-creation time via secretKeyRef. Create it with the provided script (never commit the filled-in values):

export AWS_ACCESS_KEY_ID=...
export AWS_SECRET_ACCESS_KEY=...
export JWT_SECRET=$(openssl rand -hex 32)   # must be the same value used by init-service/orchestrator-simple below
./k8s/create-secret.sh   # defaults to the "default" namespace; pass one as an arg otherwise

This creates a single sandbox-secrets Secret with AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and JWT_SECRET keys, referenced by both the init container and the runner container in service.yaml.

4. Install the ingress controller

kubectl apply -f k8s/ingress-controller.yaml

5. Run the services

init-service and orchestrator-simple both need the same JWT_SECRET (used to sign/verify anonymous session tokens) and the same OWNERSHIP_DB_PATH (a shared SQLite file recording which user owns which replId — see Auth & ownership).

Note the copy destination below: dotenv.config() loads .env from the process's working directory (i.e. the service root when you run npm run dev from there), not from src/, even though the template lives at src/.env.example. Copying it to src/.env (an easy mistake - the original version of this README did exactly that) means none of these variables actually load.

# init-service
cd init-service
npm install
cp src/.env.example .env   # fill in S3_BUCKET, AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, S3_ENDPOINT, JWT_SECRET, OWNERSHIP_DB_PATH
npm run dev                     # :3001

# orchestrator-simple
cd orchestrator-simple
npm install
cp src/.env.example .env   # same JWT_SECRET and OWNERSHIP_DB_PATH as init-service
npm run dev                     # :3002 — needs kubeconfig access to your cluster (loadFromDefault())

6. Frontend

cd frontend
npm install
cp .env.example .env   # only needed if your domains aren't peetcode.com/autogpt-cloud.com
npm run dev                     # :5173

Create a project, open it, and the frontend will call /start and wait for its pod before connecting. On first load it also silently calls POST /auth/session on init-service and caches the returned token in localStorage — see Auth & ownership.

7. (Optional) Enable TLS

Everything above runs over plain HTTP. To serve <replId>.<domain> over HTTPS, see TLS via cert-manager - it's a few extra one-time cluster steps, deliberately kept separate so the base setup above keeps working without them.

Environment variables

Variable Used by Description
S3_BUCKET init-service, runner Bucket holding templates and per-project storage
AWS_ACCESS_KEY_ID / AWS_SECRET_ACCESS_KEY init-service, runner, init container Storage credentials. In the cluster these come from the sandbox-secrets Secret (see setup step 3), not plaintext YAML.
S3_ENDPOINT init-service, runner Override for S3-compatible storage (e.g. Cloudflare R2)
PORT init-service, orchestrator-simple, runner Service port (defaults: 3001, 3002, 3001)
REPL_ID runner The project's replId, injected by the orchestrator via the same service_name substitution used elsewhere in service.yaml. Used to label the auto-run terminal session in logs.
JWT_SECRET init-service, orchestrator-simple, runner Shared HMAC secret for signing/verifying anonymous session tokens. Must be identical across all three services. Generate with e.g. openssl rand -hex 32.
OWNER_ID runner The verified owner's user id, injected by the orchestrator at pod-creation time (from the ownership row it already checked in POST /start). The runner's socket handshake rejects any token whose userId doesn't match this.
OWNERSHIP_DB_PATH init-service, orchestrator-simple Path to the shared SQLite file mapping replId → owning user. Defaults to <repo root>/data/ownership.db, which only works if both services run on the same host/volume - see the trade-off note below.
WS_DOMAIN / APP_DOMAIN orchestrator-simple The two domains projects are reachable at - <replId>.<WS_DOMAIN> for the terminal/editor socket (default peetcode.com), <replId>.<APP_DOMAIN> for the user's running app (default autogpt-cloud.com). Substituted into service.yaml's Ingress at /start time; WS_DOMAIN is also used directly to reach a pod's /shutdown//health. See Configurable domains.
IDLE_TIMEOUT_MINUTES orchestrator-simple How long a project can sit idle before the reaper auto-stops it. Default 15.
REAPER_INTERVAL_SECONDS orchestrator-simple How often the idle-timeout reaper checks started projects. Default 60.
HEALTH_CHECK_INTERVAL_SECONDS orchestrator-simple How often the crash-loop health monitor checks started projects. Default 30.
CRASH_RESTART_THRESHOLD orchestrator-simple Restart count at which a pod is considered crash-looping, even without an explicit CrashLoopBackOff reason yet. Default 5.
ALERT_WEBHOOK_URL orchestrator-simple Optional Slack-compatible webhook ({text: "..."}) fired when a project starts crash-looping. Unset = no alerting.
RATE_LIMIT_MAX / RATE_LIMIT_WINDOW_SECONDS init-service, orchestrator-simple Per-user token-bucket rate limit on POST /project / POST /start - burst size (default 5) and refill window in seconds (default 60). See Rate limiting.
VITE_WS_DOMAIN / VITE_APP_DOMAIN frontend Must match WS_DOMAIN/APP_DOMAIN above. Only need a .env at all if your domains differ from the defaults.
VITE_INIT_SERVICE_URL / VITE_ORCHESTRATOR_URL frontend Full base URLs (protocol+host+port) for init-service/orchestrator-simple, wherever you deploy them. Defaults (http://localhost:3001/:3002) only work when running everything on one machine - required for any real deployment, since the frontend runs in the user's browser, not on your server.
VITE_USE_TLS frontend Set to "true" once TLS via cert-manager is set up - switches the per-project socket/iframe connections from ws/http to wss/https. Default false.

orchestrator-simple authenticates to Kubernetes via KubeConfig().loadFromDefault() — it needs a valid kubeconfig (or in-cluster service account) available in its own environment, not an env var. See the RBAC note in setup step 2 - namespace-per-project means this now needs cluster-scoped permissions, not just access to default.

Lifecycle: stop, graceful shutdown, idle timeout

  • POST /stop (orchestrator-simple, auth + ownership gated like /start) tears a project down: it first calls the pod's POST /shutdown (see below) to flush any pending file state to S3/R2, then deletes the Deployment/Service/Ingress/NetworkPolicy. Deleting an already-missing resource (e.g. a retried or partial /stop) is treated as success, not failure - only genuine API errors surface as a 500.
  • Graceful shutdown: the runner exposes POST /shutdown, which recursively re-uploads every file under /workspace to S3/R2 (runner/src/sync.ts). This isn't recovering buffered writes - individual edits already sync to S3 immediately (see ws.ts's updateContent handler) - it's a belt-and-suspenders pass covering any edit whose S3 write raced with pod teardown. The same sync also runs on SIGTERM as a safety net, in case a pod is torn down without /stop being called first (e.g. kubectl delete pod directly). Both paths are bounded to 8s internally, and orchestrator's call to /shutdown is bounded to 10s - a stuck or unreachable pod never blocks teardown, it just proceeds anyway and logs a warning.
  • Idle-timeout reaper: the runner tracks its own last-activity timestamp in memory (ws.ts, updated on connect and on every terminal/file event) and exposes it via GET /health. A background loop in orchestrator-simple (src/reaper.ts) polls every REAPER_INTERVAL_SECONDS for all projects it thinks are running, refreshes their last-active time from /health, and calls the same stop-with-sync logic on anything idle longer than IDLE_TIMEOUT_MINUTES - logging [reaper] AUTO-TEARDOWN ... so it's auditable. A pod that's temporarily unreachable doesn't get force-reaped off one failed check; the reaper falls back to the last known activity time instead.
  • Project status (created / started / stopped) and last-active time live in the same SQLite ownership table from Priority 2, with a migration that adds these columns to a pre-existing DB file if needed.
  • Trade-off: /shutdown and /health are not token-gated like the rest of the API (see Auth & ownership) - they're internal, orchestrator-only endpoints reachable at the same ingress host as the user-facing app. Worst case impact is low (an unauthenticated caller can force an early resync or read a timestamp, nothing destructive), but a shared internal secret would be a natural hardening step if this matters for your deployment.
  • Not implemented: pod pre-warming (Priority 3's explicit stretch goal) - deferred since 1-3 needed to be solid first, and warm-pool management is a meaningfully bigger scope than the rest of this tier.

Monitoring & guardrails

  • Per-pod resource usage (orchestrator-simple/src/monitor.ts): reads live CPU/memory from the Kubernetes Metrics API (metrics.k8s.io, via @kubernetes/client-node's Metrics client), not just the static resources.limits already in the manifest. Requires metrics-server installed in your cluster - if it's not, this fails closed (returns null per project) rather than breaking health checks or /status.
  • Crash-loop / OOM detection (src/healthMonitor.ts): a background loop, separate from the idle reaper, checks every started project's pod status via the Kubernetes API every HEALTH_CHECK_INTERVAL_SECONDS. A pod is considered crash-looping if its container reports the CrashLoopBackOff waiting reason or its restart count reaches CRASH_RESTART_THRESHOLD (whichever fires first - the threshold catches the slower-burning case where kubelet hasn't reported that reason yet). OOMKilled is detected separately from the container's last-terminated reason and reported alongside.
  • Throttled response, not silent auto-restart: this project never restarts pods itself (kubelet already owns that via restartPolicy). What "stop trying to auto-recover" means here concretely: once a project crosses the crash-loop threshold, it's marked unhealthy in the ownership table (a health_status column, orthogonal to the started/stopped lifecycle status - a pod can be started and unhealthy at the same time) and stops being silently treated as fine. Recovery is automatic and symmetric: the next check that finds the pod no longer crash-looping flips it back to healthy.
  • GET /status (orchestrator-simple, auth required, not ownership-scoped - see trade-off below): the cluster-wide operational view - total active pods, unhealthy count, each active project's health/restart-count/resource-usage, recent auto-teardowns (from the idle reaper), and recent crash-loop alerts.
  • GET /projects/:replId/status: the ownership-scoped counterpart, for the frontend - returns just one project's lifecycle status, health status, restart count, and reason. CodingPage.tsx polls this every 20s and shows a banner ("this project's pod is unhealthy...") when it comes back unhealthy, instead of a silently broken terminal.
  • Alerting webhook (optional): set ALERT_WEBHOOK_URL to a Slack incoming-webhook URL (or any endpoint that accepts {text: "..."} - Discord and log-sink proxies both work this way) and a message fires the moment a project crosses into unhealthy. No webhook configured = alerts still land in /status and logs, just no push notification.
  • Trade-off: /status requires a valid token but isn't restricted to an admin role (there is no role concept in this project) - any authenticated caller can see every project's replId/ownerId/health data, not just their own. Acceptable for a portfolio-scale deployment; real multi-tenant use would need an admin flag on top of the existing auth.

Auth & ownership

There is no login/password/email anywhere in this project - adding real user accounts was out of scope. Instead:

  1. On first load, the frontend calls POST /auth/session on init-service (no auth required - this is the bootstrap), which generates a random userId (crypto.randomUUID()), signs a JWT { userId }, and returns it. The frontend caches this token in localStorage and sends it as Authorization: Bearer <token> on /project and /start, and as { auth: { token } } on the Socket.IO connection to the pod.
  2. POST /project (init-service) requires a valid bearer token, rejects a replId that's already taken (409), and records (replId, ownerId, createdAt) in a shared SQLite table.
  3. POST /start (orchestrator-simple) requires a valid bearer token, looks up the replId's owner, and rejects with 404 if the project doesn't exist or 403 if the caller isn't the owner. On success, it injects the verified ownerId into the pod as OWNER_ID (same substitution mechanism as REPL_ID) - no DB access needed inside the pod itself.
  4. The runner's Socket.IO connection handler verifies the token in the handshake (socket.handshake.auth.token) and disconnects unless the token's userId matches the pod's own OWNER_ID.

This is intentionally a lightweight, anonymous, device-bound identity, not a real auth system - a token just proves "the same browser that created this project is asking again." Clearing localStorage forfeits access to your own projects (no recovery mechanism), and there's no protection against someone deliberately exporting/sharing their token. Swapping in a real identity provider later would only require changing how /auth/session issues tokens - everything downstream (the bearer-token middleware, the ownership table, the socket check) stays the same.

Trade-off on OWNERSHIP_DB_PATH: init-service and orchestrator-simple both read/write the same SQLite file directly rather than one service calling the other's API. That's the lightest option for two services that, today, are expected to run on the same host - but it means they must share a filesystem. If you deploy them on separate hosts/containers, either point OWNERSHIP_DB_PATH at a shared volume, or (better, for real multi-host deployment) replace the direct file access with a tiny internal ownership API that one service exposes and the other calls.

Automatic run step

On startup, the runner scans /workspace (already populated by the init container by the time the main container starts) and, best-effort, kicks off an install+start command in a dedicated background terminal session (runner/src/autorun.ts) so the Output iframe has something listening on port 3000 without the user typing commands manually:

  1. Procfile at the workspace root (web: <command>) — wins over everything else, for projects that need a start command the heuristics below don't cover.
  2. package.json — npm install, then npm run dev if a dev script exists, else npm start if a start script exists, else install only.
  3. requirements.txt — pip install -r requirements.txt, then python app.py/main.py/server.py (first one found), else install only.
  4. Otherwise, autorun does nothing and the pod behaves exactly as before (manual terminal use).

This never blocks or crashes pod startup — detection and command failures are caught and logged (visible via pod logs, prefixed [autorun]), leaving the pod up so the user can intervene manually. The auto-run session lives in the same TerminalManager registry as user terminals but under its own session id, so it's fully independent of whatever terminal(s) the user opens.

Trade-off: auto-run output currently goes to the pod's stdout logs only, not to the user's terminal UI — piping it into the frontend would mean extending the Socket.IO protocol with a second output stream, which felt like more surface area than this fix warranted. Worth revisiting if users want to see install/start logs live.

Network policy

Each project's Deployment/Service/Ingress is now accompanied by a fourth manifest doc, a NetworkPolicy scoped to that pod (app: <replId>), created and torn down the same way as the others:

  • Ingress: only the ingress controller (namespace ingress-nginx by default - matches k8s/ingress-controller.yaml) may reach the pod's ports 3001/3000. Every other pod, including other projects' runner pods, is blocked from connecting directly.
  • Egress: DNS is allowed unconditionally (needed for S3/R2 and npm/pip registries); everything else is allowed except the cluster's own pod and service CIDRs - which is what stops a pod from reaching another project's pod or the Kubernetes API server, while still permitting normal internet access (installs, S3/R2).

Two things to check before relying on this:

  • Your CNI must enforce NetworkPolicy. Calico, Cilium, and Weave Net do; plain flannel does not - the objects get created but silently ignored. If you're on flannel, switch to Canal or a policy-enforcing CNI.
  • The CIDR placeholders are generic kubeadm defaults (10.244.0.0/16 pod CIDR, 10.96.0.0/12 service CIDR) and will be wrong for many managed clusters (EKS/GKE/AKS/k3s all differ). Confirm yours (kubectl cluster-info dump | grep -m1 cluster-cidr, and check your provider's docs for the service CIDR) and edit orchestrator-simple/service.yaml before relying on this in production.

Namespace isolation

Every project now gets its own Kubernetes namespace (sandbox-<replId>, orchestrator-simple/src/namespace.ts), not a shared default - real RBAC/quota/naming isolation to sit alongside the NetworkPolicy work above, and it simplifies teardown to a single deleteNamespace call instead of four separate resource deletes (stop.ts).

  • POST /start creates the namespace first (idempotent - a 409 "already exists" is treated as success, not an error, so retrying or restarting a previously-stopped project both just work).
  • POST /stop and the idle reaper delete the whole namespace, which cascades the Deployment/Service/Ingress/NetworkPolicy automatically.
  • The crash-loop health monitor and resource-usage checks look up pods in the project's own namespace, not default.
  • Trade-off: namespace deletion is asynchronous in Kubernetes (a Terminating phase with finalizers) - this repo's deleteNamespace call returning doesn't mean the namespace is actually gone yet. A rapid stop-then-immediately-restart of the same replId can hit a conflict creating the new namespace while the old one is still terminating. In practice this resolves itself within seconds to a couple minutes; there's no special handling for it here (a fixed retry-with-backoff on ensureNamespace would be the natural next step if this becomes a real pain point).
  • RBAC trade-off: see the note in Getting started, step 2 - this needs cluster-scoped permissions now, not a namespace-scoped Role.

Cluster capacity & retries

Kubernetes accepts a Deployment even when no node can ever schedule its pod - that failure only shows up later as the pod sitting in Pending with a PodScheduled=False/Unschedulable condition, not as a thrown error from the create call. orchestrator-simple/src/capacity.ts handles both halves of this:

  • Retry-with-backoff (withRetry) around each resource-create call, for transient apiserver errors (5xx) - up to 3 attempts with exponential backoff. A 4xx (bad request, conflict, quota exceeded) never gets retried, since retrying won't change the outcome.
  • Schedulability check (checkPodSchedulable): after creating resources, /start waits a few seconds and polls the new pod's status for that Unschedulable condition. If found, it rolls back (deletes the namespace) and returns a clear 503 with a Retry-After header instead of falsely reporting success on a pod that will never run. If the pod's still ambiguously Pending when the check window closes, it's treated as schedulable rather than false-positive a rollback - the crash-loop health monitor catches genuinely stuck pods later regardless.
  • Clean error responses (translateK8sError): raw Kubernetes API error bodies never reach the frontend - a 409 becomes "resources already exist," a quota-exceeded 403 becomes a 503 capacity message, everything else becomes a generic "unexpected cluster error."
  • Trade-off: the schedulability check adds a real, unavoidable ~4-8s of latency to every successful /start call (the fixed delay before the scheduler could plausibly have reacted, plus a bounded poll window). A queued-start pattern (accept the request immediately, poll asynchronously, let the frontend poll a status endpoint) would avoid blocking the request but is meaningfully more infrastructure - a queue, a worker, client-side polling for "still starting" - and wasn't pursued given this is explicitly a lighter alternative the brief called out.

Rate limiting

POST /project (init-service) and POST /start (orchestrator-simple) are both rate-limited per authenticated user (the JWT's userId), not per IP - an IP-based limit is trivially bypassed with multiple devices/browsers and doesn't distinguish two different users behind the same NAT. Each service has its own small token-bucket middleware (src/rateLimit.ts, duplicated rather than shared, matching this project's existing pattern for small self-contained modules): a burst of RATE_LIMIT_MAX requests (default 5) is allowed immediately, then tokens refill continuously over RATE_LIMIT_WINDOW_SECONDS (default 60s). Exceeding it returns 429 with a Retry-After header.

Trade-off: buckets live in memory, per process - they reset if the service restarts, and wouldn't be shared across multiple replicas if either service were ever horizontally scaled (a Redis-backed limiter would be the natural upgrade there). A periodic sweep evicts buckets idle for over an hour so memory doesn't grow unbounded over a long-running process.

Configurable domains

The two hostnames every project is reachable at are no longer hardcoded into the committed service.yaml - service.yaml now contains ws_domain_placeholder/app_domain_placeholder tokens, substituted at /start time from orchestrator-simple's WS_DOMAIN/APP_DOMAIN env vars (same mechanism as service_name). The frontend needs the matching VITE_WS_DOMAIN/VITE_APP_DOMAIN build-time env vars (only required if you're not using the peetcode.com/autogpt-cloud.com defaults) - see frontend/.env.example.

All frontend-side backend addresses now live in one place, frontend/src/lib/config.ts:

  • VITE_INIT_SERVICE_URL / VITE_ORCHESTRATOR_URL - full base URLs for init-service/orchestrator-simple. These are not subdomains of anything, unlike the per-project hosts - they're two ordinary services you host wherever you like, so the defaults (http://localhost:3001/:3002) only work when everything runs on one machine. This is the one env var pair you must set for any deployment that isn't local dev - without it, every browser that loads the deployed frontend tries to reach its own localhost, which has nothing listening on it.
  • VITE_USE_TLS - a single flag switching the per-project socket (ws/wss) and iframe (http/https) connections together, since both project domains share one wildcard cert (see TLS via cert-manager). Enabling TLS backend-side does nothing for the browser until this is also set.

Verified in a real dev-server session (not just by reading the code): with no .env, the auth-bootstrap request correctly targeted http://localhost:3001; after setting a .env with distinct custom values for VITE_INIT_SERVICE_URL/VITE_ORCHESTRATOR_URL and restarting Vite, inspecting the actual transformed module in the browser confirmed both constants resolved to the overridden values.

TLS via cert-manager

By default everything in this repo runs over plain HTTP. Enabling HTTPS for every <replId>.<domain> subdomain deliberately does not mean issuing a new Let's Encrypt certificate per project - Let's Encrypt rate-limits certificates per registered domain per week, and this architecture can create and destroy projects (and their subdomains) far faster than that. Instead:

  1. Install cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml
  2. Apply k8s/cluster-issuer.yaml - a Let's Encrypt ClusterIssuer using a DNS01 challenge (required for wildcard certs; HTTP01 doesn't support them). The template uses Cloudflare as the DNS solver - fill in your API token and email, and swap the cloudflare block for your provider's solver if you're not on Cloudflare.
  3. Apply k8s/wildcard-certificate.yaml - one certificate covering *.<WS_DOMAIN> and *.<APP_DOMAIN> (edit the two domains in the file first). This is issued once and renewed automatically by cert-manager, producing a single wildcard-tls Secret in the ingress-nginx namespace.
  4. Uncomment the --default-ssl-certificate=ingress-nginx/wildcard-tls line in k8s/ingress-controller.yaml and re-apply it (kubectl apply -f k8s/ingress-controller.yaml).

That's the whole mechanism: every project's Ingress deliberately has no tls: block of its own - the ingress controller's cluster-wide default certificate (step 4) covers every subdomain via SNI automatically, so HTTPS "just works" for new projects with zero additional cert-manager activity per project. Steps 1-4 are one-time cluster setup, not something /start does per project.

Why this is commented out / opt-in by default: uncommenting --default-ssl-certificate before the referenced secret exists makes the ingress controller pod fail to start entirely - not just break TLS, break HTTP too. Leaving it commented keeps the base HTTP-only setup working for anyone who hasn't done the cert-manager steps yet.

Deploying the schedulers

Everything above assumes init-service and orchestrator-simple are just running via npm run dev somewhere - that's still completely valid (a VM, a plain Docker host, anywhere with network access to your cluster's API server), and the two Dockerfiles below are all you need for that path. This section is for running them inside the same cluster they manage, which is the more self-contained option.

Both Dockerfiles were actually built and run (Docker was available in this environment) rather than just written and assumed correct, which caught two real, pre-existing bugs neither of which had anything to do with the Dockerfiles themselves:

  • No .dockerignore anywhere in the repo (all three services). Without one, COPY . . copies the host's node_modules into the image, silently overwriting the correctly-Linux-compiled native better-sqlite3 binary that npm install had just built inside the container - the container crashed on startup with invalid ELF header. Added .dockerignore (excluding node_modules, dist, .env) to all three services - this bug was equally latent in runner's Dockerfile, just never triggered.
  • orchestrator-simple/tsconfig.json never had outDir/rootDir set (unlike init-service's otherwise-identical config), so tsc -b compiled every .ts file to a .js file next to it inside src/ instead of into dist/ - meaning node dist/index.js (this Dockerfile's CMD, and npm run start) has never actually worked for orchestrator-simple, going back before any of the work in this README's changelog. Fixed by setting rootDir: "./src" / outDir: "./dist" to match init-service.

After both fixes, each image was built, run, and hit with real HTTP requests: init-service's container correctly issued a signed JWT from POST /auth/session; orchestrator-simple's container started its reaper and health-monitor background loops and correctly returned 401 on unauthenticated /status and /start calls.

1. Build and push both images

cd init-service && docker build -t <your-registry>/init-service:latest . && docker push <your-registry>/init-service:latest && cd ..
cd orchestrator-simple && docker build -t <your-registry>/orchestrator-simple:latest . && docker push <your-registry>/orchestrator-simple:latest && cd ..

2. Grant orchestrator-simple in-cluster permissions

kubectl apply -f k8s/rbac.yaml

This creates a sandbox-orchestrator ServiceAccount + ClusterRole + ClusterRoleBinding covering exactly what orchestrator-simple needs: create/delete namespaces (see Namespace isolation), create/delete Deployments/Services/Ingresses/NetworkPolicies inside them, read-only pods (crash-loop detection) and metrics.k8s.io (resource usage). @kubernetes/client-node's loadFromDefault() picks this ServiceAccount's mounted token up automatically once the Deployment below references it - no kubeconfig file, no extra env var.

3. Apply the Secret, config, storage, and Deployments

./k8s/create-secret.sh   # if you haven't already (see step 3 of the main setup)
kubectl apply -f k8s/scheduler-services.yaml

Edit the image references, S3_BUCKET/S3_ENDPOINT/WS_DOMAIN/APP_DOMAIN in the ConfigMap, and the two host: values in the Ingress before applying - same pattern as service.yaml, just edited directly since this file is applied once, not templated per-project.

Storage note: init-service and orchestrator-simple share the SQLite ownership file (see the trade-off note under Auth & ownership) via a single PersistentVolumeClaim mounted ReadWriteMany into both pods. Not every cluster supports RWX out of the box - AWS EBS, GCE PD, and Azure Disk are all ReadWriteOnce-only; you need something like EFS/Filestore/Azure Files/NFS/Longhorn. If that's not available to you, the fallback is running both containers in one Pod sharing a plain emptyDir instead of a PVC - works everywhere, at the cost of coupling their restarts/scaling together (a straightforward adaptation of the manifest, not provided as a separate file here).

Networking note: init.<WS_DOMAIN> and api.<WS_DOMAIN> are ordinary single-level subdomains, so if you've done the TLS setup they're already covered by the same wildcard certificate - no extra cert-manager work.

4. Point the frontend at them

VITE_INIT_SERVICE_URL=http://init.peetcode.com
VITE_ORCHESTRATOR_URL=http://api.peetcode.com

(https:// once TLS is enabled - see VITE_USE_TLS).

Trade-off: orchestrator-simple's own outbound calls and hairpin NAT

/stop's final-sync call and the idle reaper's health checks (stop.ts/reaper.ts) reach a runner pod via its public ingress hostname (http://<replId>.<WS_DOMAIN>/shutdown) - orchestrator-simple has no other network path to it today. That's harmless when orchestrator-simple runs outside the cluster (normal internet routing), but once it runs inside the same cluster, that request has to leave the cluster via the ingress controller's external IP/LoadBalancer and route back in - "hairpin NAT" - which not every cloud provider or bare-metal LoadBalancer setup supports cleanly. Where it doesn't work, every /stop call's final sync and every reaper health check will time out (harmlessly - both paths are already bounded and fail gracefully - but the graceful-shutdown and idle-detection features effectively stop doing anything useful).

Not fixed here - the correct fix is having orchestrator-simple reach runner pods via in-cluster Service DNS (http://<replId>.sandbox-<replId>.svc.cluster.local:3001) instead of the public hostname when it's running in-cluster, which also means extending the NetworkPolicy's ingress rule to allow orchestrator-simple's own namespace, not just ingress-nginx. That's a real architecture change to the request path (not just a deployment manifest), so it wasn't made unilaterally - flagging it clearly here instead. If you deploy orchestrator-simple in-cluster and rely on /stop's final sync or the idle reaper, test whether hairpin NAT works on your cluster first.

Known limitations

  • Auth is anonymous/device-bound, not a real identity system - see Auth & ownership. Good enough to stop strangers from hijacking a replId they don't own; not a substitute for real accounts.
  • init-service and orchestrator-simple must share a filesystem for the SQLite ownership store today (see the trade-off note under Auth & ownership) - a shared volume (a ReadWriteMany PVC in-cluster, see Deploying the schedulers) satisfies this, but not every cluster has RWX storage available.
  • orchestrator-simple's own outbound calls (final sync, health checks) go through the public ingress, which can hit hairpin-NAT issues once it runs inside the same cluster it manages - see the trade-off note in Deploying the schedulers. Not an issue when it runs outside the cluster (the default assumption everywhere else in this README).
  • No frontend "Stop" button. POST /stop exists and is fully wired up, but nothing in the UI calls it yet - today it's reachable but not user-facing.
  • No pod pre-warming. Cold starts pay the full init-container S3 copy + image pull cost every time; this was explicitly deferred as a stretch goal (see Lifecycle).
  • Resource usage monitoring requires metrics-server. Without it, CPU/memory numbers in /status are always null (fails closed, doesn't break anything else) - the static resources.limits in the manifest are still enforced by Kubernetes itself either way, this only affects the visibility into usage.
  • /status isn't admin-scoped. Any authenticated (anonymous) caller can see every project's health/resource data cluster-wide, not just their own - see the trade-off note under Monitoring & guardrails.
  • /start has an unavoidable ~4-8s capacity-check delay, and a rapid stop-then-restart of the same replId can occasionally race a still-terminating namespace - see Cluster capacity & retries and Namespace isolation.
  • Rate-limit buckets are in-memory, per-process - reset on restart, not shared across replicas. See Rate limiting.
  • No queued-start pattern. A cluster with no capacity returns a clear 503 (see Cluster capacity & retries), but the client has to retry itself - there's no server-side queue that automatically starts the project once capacity frees up.
  • TLS is opt-in and cluster-wide, not per-project. Every project shares one wildcard certificate rather than getting its own - see TLS via cert-manager for why, and note it's commented out by default so a fresh setup isn't forced through the cert-manager steps just to get HTTP working.

This repo is the second iteration of Session Multiplexer Code Shell, Same editor/terminal experience, rebuilt around per-project Kubernetes scheduling instead of a single shared host.

Changelog

Priority 1 — bug fixes (2026-07-26)

  • Fixed TerminalManager session-cleanup bug (runner/src/pty.ts): the PTY exit handler deleted this.sessions[term.pid] instead of this.sessions[id] — since sessions are keyed by the caller-supplied id (a Socket.IO socket.id), that delete was effectively a no-op on every natural shell exit, leaving a stale entry pointing at a dead process. Fixed to close over the original id. Also hardened clear() to no-op on an unknown/already-removed id instead of throwing, and added has()/getActiveSessionIds() for introspection (used by the new test, and generally useful for future status/monitoring work).
    • Also fixed a related leak: runner/src/ws.ts's disconnect handler never called terminalManager.clear(), so every browser disconnect leaked its PTY process server-side indefinitely. It now clears the socket's terminal session on disconnect.
    • Verification: runner/src/pty.manualtest.ts (npm run test:pty from runner/) creates two terminal sessions, exits one naturally (exit typed into the shell — the exact path that hit the bug), and asserts: the exited session is untracked and its OS process is dead, the other session is untouched and still alive, and clear() is idempotent on unknown ids.
  • Added an automatic run step (see above) so pods do something useful on start instead of requiring the user to manually run install/start commands.

Both changes are scoped to runner/ (plus one new env: entry in orchestrator-simple/service.yaml for REPL_ID); no frontend changes were required for this tier.

Priority 2 — security (2026-07-26)

  • Credentials out of the plaintext manifest. AWS_ACCESS_KEY_ID/AWS_SECRET_ACCESS_KEY in orchestrator-simple/service.yaml are now secretKeyRefs against a sandbox-secrets Kubernetes Secret, created out-of-band via the new k8s/create-secret.sh (reads values from your shell env, never contains real credentials itself). Also fixed a latent gap while touching this: the runner container never actually received S3 credentials before (only the init container did), so saveToS3 had no working credentials in the current manifest at all - it now gets them via the same Secret. Added a root .gitignore so a locally-filled-in secret manifest or the SQLite ownership file can't be committed by accident.
  • JWT auth + SQLite ownership records, closing the "anyone who knows a replId can /start it" gap:
    • New POST /auth/session on init-service mints an anonymous, device-bound identity token (see Auth & ownership for the full model and its trade-offs).
    • POST /project and POST /start both require a valid bearer token now; /project also rejects an already-taken replId (409) instead of silently overwriting it, closing a gap the code's own comment had flagged (// Hit a database to ensure this slug isn't taken already).
    • POST /start rejects replIds the caller doesn't own (403) or that don't exist (404), and injects the verified owner into the pod as OWNER_ID.
    • The runner's Socket.IO handshake now requires a token matching that pod's OWNER_ID, closing the same gap at the terminal/file-access layer, not just the HTTP layer.
    • New files: {init-service,orchestrator-simple}/src/{auth,db}.ts, runner/src/auth.ts, frontend/src/lib/auth.ts. New deps: jsonwebtoken (all three backend services), better-sqlite3 (init-service, orchestrator-simple).
    • Frontend changes were required and made: Landing.tsx/CodingPage.tsx attach the bearer token to /project//start, and CodingPage.tsx's socket connection now waits for a token before connecting and passes it via { auth: { token } }.
    • Verified functionally (not just type-checked): a smoke test drove signToken/verifyToken through a round trip and createProject/getProject against a real SQLite file, confirming token verification, ownership lookups, the duplicate-replId unique constraint, and invalid-token rejection all behave correctly.
  • NetworkPolicy per project - see Network policy above for what it does and its two important caveats (CNI enforcement, cluster-specific CIDRs).
  • Incidental fix: pinned @types/node in all three backend services' devDependencies. A fresh npm install was pulling in an unpinned transitive @types/node@20.11.19, which is incompatible with TypeScript 5.9's typed-array generics and broke orchestrator-simple/src/aws.ts's type-check - unrelated to this tier's changes, but it was blocking verification of everything else here.

Frontend, init-service, and orchestrator-simple all required changes in this tier (auth is inherently cross-cutting); runner needed both the socket-auth check and the Secret-based env wiring.

Priority 3 — lifecycle management (2026-07-26)

  • POST /stop (orchestrator-simple): auth + ownership gated like /start; calls the pod's /shutdown for a final sync, then deletes Deployment/Service/Ingress/NetworkPolicy. Already-missing resources (404) are treated as success, not failure - /stop is safe to retry.
  • Graceful shutdown: new runner/src/sync.ts recursively re-uploads /workspace to S3/R2, exposed via POST /shutdown and also wired to SIGTERM as a safety net for direct pod deletion. Both paths are bounded (8s internally, 10s from orchestrator's side) so a stuck sync can't block teardown indefinitely.
  • Idle-timeout reaper: the runner now tracks its own last-activity timestamp in memory (ws.ts) and exposes it via GET /health; a background loop in orchestrator-simple (src/reaper.ts) polls every project it thinks is running, refreshes last-active from /health, and calls the same stop-with-sync logic on anything idle past IDLE_TIMEOUT_MINUTES (default 15), logging every auto-teardown.
  • The SQLite ownership table (from Priority 2) grew two columns - status (created/started/stopped) and last_active_at - with a defensive ALTER TABLE migration so an existing pre-Priority-3 DB file doesn't break.
  • Pod pre-warming was not attempted - it's explicitly called out as a stretch goal in the brief, to be pursued only once 1-3 are solid, and warm-pool management is a meaningfully larger scope than the rest of this tier.
  • Verified functionally, not just type-checked, using the actual shipped code (only the Kubernetes API client and DNS resolution were faked for the test environment):
    • syncWorkspaceToS3 against a real nested directory tree - confirmed every file gets uploaded with the correct relative path and S3 key prefix, and withTimeout correctly races both a slow and a fast promise.
    • The full reaper loop (reapOnce) against a real SQLite DB and a local HTTP server standing in for two pods (one idle 20 minutes, one fresh): confirmed only the idle one gets torn down, its status flips to stopped, the fresh one is untouched, and all four k8s resource types get deleted for the idle one.
    • stop.ts's error handling: a 404 from one resource doesn't fail the whole stop (idempotent teardown), while a genuine 500 correctly surfaces.
    • The DB schema migration: simulated an old Priority-2-era 3-column DB file, confirmed the new columns get added without data loss and default correctly.

No frontend changes in this tier - /stop exists and works but isn't called from the UI yet (see Known limitations).

Priority 4 — resource guardrails & monitoring (2026-07-26)

  • Per-pod resource monitoring (orchestrator-simple/src/monitor.ts): live CPU/memory via the Kubernetes Metrics API, fails closed to null per project (not an exception) if metrics-server isn't installed.
  • Crash-loop / OOM detection (src/healthMonitor.ts): a new background loop, separate from the idle reaper, flags a project unhealthy when its pod reports CrashLoopBackOff or crosses CRASH_RESTART_THRESHOLD restarts, and separately flags OOMKilled. Recovery is automatic and symmetric - the next healthy check flips it back.
  • Throttled response, not silent restart-forever: added a health_status column (orthogonal to the existing lifecycle status) so "pod exists but is broken" is a distinct, queryable state instead of silently indistinguishable from "pod exists and is fine."
  • GET /status: cluster-wide operational endpoint - active pod count, unhealthy count, per-project health/restart-count/resource-usage, recent auto-teardowns, recent crash-loop alerts.
  • GET /projects/:replId/status: ownership-scoped single-project counterpart, consumed by a new polling hook in CodingPage.tsx that shows an "unhealthy pod" banner - closing the loop the brief asked for ("surfaced to the frontend so the user sees this project's pod is unhealthy").
  • Alerting webhook (stretch goal, implemented): ALERT_WEBHOOK_URL, Slack-compatible payload, fires once per transition into unhealthy (not on every check tick).
  • Verified functionally, not just type-checked, with fake (not real-cluster) Kubernetes API responses standing in for listNamespacedPod/getPodMetrics:
    • checkPodHealth correctly classifies a CrashLoopBackOff pod, an OOMKilled pod (detected via lastState.terminated.reason, separate from the crash-loop check), a healthy pod, and a missing pod.
    • getPodResourceUsage fails closed to null when the metrics API throws (simulating no metrics-server), rather than propagating the error.
    • A full monitorOnce pass against a real SQLite DB: two crash-looping projects (one via explicit reason, one via restart-count threshold) correctly get marked unhealthy with the right reason recorded, a third healthy project is untouched, and both alerts land in the in-memory alert log.
    • The alert webhook: confirmed (in an isolated repro after an initial test read its output file too early) that the real payload - project id, owner, reason, restart count - actually reaches an HTTP endpoint.

All four backend/frontend surfaces type-check cleanly; the frontend banner addition introduced no new type errors (confirmed against the same 14 pre-existing ones from Priority 2, now at shifted line numbers).

Priority 5 — scaling & robustness (2026-07-26)

  • Cluster capacity handling (orchestrator-simple/src/capacity.ts): retry-with-backoff around resource creation for transient (5xx) API errors; a schedulability check after creation that detects a pod stuck Unschedulable and rolls back with a clear 503 instead of falsely reporting success; raw Kubernetes error bodies are translated into clean messages instead of ever reaching the frontend. A queued-start pattern (the heavier alternative the brief mentioned) was not pursued - documented as a trade-off.
  • Per-user rate limiting (src/rateLimit.ts, duplicated in both init-service and orchestrator-simple): token-bucket keyed by the authenticated userId, not IP, on POST /project and POST /start. Configurable burst size and refill window; a periodic sweep evicts idle buckets so memory doesn't grow unbounded.
  • Namespace-per-project isolation (stretch goal, implemented): orchestrator-simple/src/namespace.ts - every project gets its own sandbox-<replId> namespace instead of sharing default, created idempotently at /start and deleted wholesale at /stop (which also simplified stop.ts from four resource deletes to one namespace delete). Documented trade-offs: namespace deletion is asynchronous (a rapid stop-then-restart can race a still-terminating namespace), and this raises the RBAC bar from a namespaced Role to cluster-scoped permissions.
  • Incidental fix, found while touching env-var loading for this tier: the README's setup instructions (inherited from before Priority 1) told users to cp src/.env.example src/.env for init-service/orchestrator-simple - but dotenv.config() defaults to loading .env from the process's working directory, which is the service root when running npm run dev, not src/. Every env var this project uses (JWT_SECRET, OWNERSHIP_DB_PATH, etc., across every prior tier) would silently fail to load under the old instructions. Fixed the copy destination in the README, and added .env to .gitignore in all three backend services and the frontend (previously only node_modules was ignored for the backend services - a real gap, since .env would hold live AWS/JWT secrets).
  • Verified functionally, not just type-checked, with fake Kubernetes API responses and fake request/response objects:
    • namespaceForProject naming, ensureNamespace's idempotent handling of a 409 (and correct rethrow of non-409 errors), deleteProjectNamespace's tolerance of 404.
    • withRetry: retries a flaky call that fails twice with 503 then succeeds; does not retry a 400; exhausts its attempts and throws when a call always fails.
    • checkPodSchedulable against three fake pod states: an explicit Unschedulable condition (detected in ~4s), a Running pod (detected in ~4s), and a pod stuck ambiguously Pending with no clear condition (correctly falls back to "schedulable" after the full ~12s check window - confirmed by actually waiting it out, not by inspecting the code).
    • translateK8sError's three branches (409, quota-exceeded 403, generic).
    • The rate limiter: a burst of RATE_LIMIT_MAX requests succeeds and the next one is blocked with 429+Retry-After; a second user's bucket is completely unaffected by the first user exhausting theirs; after waiting out the refill window, the first user can make requests again.

Priority 6 — networking & polish (2026-07-26)

  • Configurable domains: service.yaml's two Ingress hostnames are now ws_domain_placeholder/app_domain_placeholder tokens, substituted at /start time from orchestrator-simple's WS_DOMAIN/APP_DOMAIN env vars (same mechanism as service_name) - no more editing real domains into a template that gets committed. The frontend gained matching VITE_WS_DOMAIN/VITE_APP_DOMAIN build-time env vars and a .env.example (it previously had none).
  • TLS via cert-manager: rather than issuing a certificate per ephemeral project (which risks Let's Encrypt's per-domain rate limits at this churn rate), every project shares one wildcard certificate covering both configured domains, applied once via k8s/cluster-issuer.yaml + k8s/wildcard-certificate.yaml and wired in as the ingress controller's cluster-wide default certificate (k8s/ingress-controller.yaml, one new arg). No per-project Ingress needs its own tls: block or any cert-manager annotation - HTTPS "just works" for every new subdomain with zero additional cert-manager activity per project start. Left commented out by default so a fresh HTTP-only setup isn't forced through the cert-manager steps.
  • Verified: all new/edited k8s YAML (ingress-controller.yaml, cluster-issuer.yaml, wildcard-certificate.yaml, service.yaml) parses without errors; the full manifest substitution (all four placeholder types together) was re-validated end to end.

Frontend, init-service, and orchestrator-simple all changed in these two tiers; runner was untouched (P5/P6 are entirely about the scheduling/networking layer, not the per-pod runtime).

Frontend deployment wiring (follow-up, 2026-07-26)

After the six priority tiers above, a review of "is this actually deployable" turned up that the frontend still hardcoded http://localhost:3001/:3002 for init-service/orchestrator-simple in three places (lib/auth.ts, Landing.tsx, CodingPage.tsx), and hardcoded ws:///http:// (never wss/https) for the per-project connections - meaning the TLS work in Priority 6 had no effect on actual browser traffic. Fixed by centralizing every backend address into frontend/src/lib/config.ts (VITE_INIT_SERVICE_URL, VITE_ORCHESTRATOR_URL, VITE_USE_TLS, alongside the existing VITE_WS_DOMAIN/VITE_APP_DOMAIN). Verified in a live dev-server session, not just by reading the code - see Configurable domains for what was actually checked.

Scheduler deployment packaging (follow-up, 2026-07-26)

The same deployability review flagged three remaining gaps: no Dockerfile/deployment manifest for init-service or orchestrator-simple themselves (only the runner image they deploy per-project was containerized), no RBAC for running orchestrator-simple in-cluster with least privilege, and the shared-SQLite-file constraint had no concrete deployment story. All three addressed - see Deploying the schedulers for the full detail:

  • Dockerfiles for both services (mirroring the runner's pattern).
  • k8s/rbac.yaml - a ServiceAccount/ClusterRole/ClusterRoleBinding scoped to exactly what orchestrator-simple needs, so it can run with an in-cluster identity instead of a mounted admin kubeconfig.
  • k8s/scheduler-services.yaml - ConfigMap + ReadWriteMany PersistentVolumeClaim (for the shared ownership DB) + Deployment/Service for each + an Ingress exposing both, reusing the existing wildcard certificate.
  • Documented, not fixed: a hairpin-NAT risk in orchestrator-simple's own outbound calls once it runs in-cluster (see the trade-off note in that section) - a real architecture change to the request path, flagged rather than made unilaterally.
  • Incidental cleanup: orchestrator-simple/src/aws.ts and its S3/AWS env vars were dead code - never imported anywhere, presumably copy-pasted from init-service's template originally. Removed, along with the now-unused aws-sdk dependency.
  • Two real, pre-existing bugs found and fixed by actually building and running both Docker images (detailed in Deploying the schedulers): a missing .dockerignore that let the host's Windows-compiled node_modules shadow the container's correctly Linux-compiled ones, and orchestrator-simple/tsconfig.json never having outDir/rootDir set, meaning its production build (dist/index.js) had never actually worked. Both were verified fixed by rebuilding, running each container, and hitting it with real HTTP requests.

Unhandled-rejection crash bug across all three backend services (follow-up, 2026-07-26)

Verifying the runner image with a real socket.io-client connection (not just an HTTP curl) - the only way to actually exercise the terminal/editor path - crashed the whole container the moment a real client connected: an unguarded await fetchDir("/workspace", "") in ws.ts's connection handler rejected (nothing had populated /workspace in the test container), and since Node terminates the process on an unhandled promise rejection by default, that took down the entire pod - every session in it, not just the one bad connection.

Auditing for the same pattern found it was systemic, not a one-off:

  • runner/src/ws.ts: every single async socket handler (fetchDir, fetchContent, updateContent, requestTerminal, terminalData, plus the connection handler's initial workspace load) was unguarded. All now wrapped in try/catch, logging and degrading gracefully (empty results, or just logging for fire-and-forget events) instead of crashing.
  • init-service/src/index.ts: POST /project's await copyS3Folder(...) had no try/catch - a real, live risk (any S3 error - bad credentials, network blip, unknown language folder - would have crashed the process for every user, not just the failing request). Fixed.
  • orchestrator-simple/src/index.ts: GET /status's Promise.all had no try/catch. getPodResourceUsage already catches internally today so this wasn't currently reachable, but the endpoint shouldn't depend on that never changing - a status dashboard failing should 500, not take /start, /stop, the reaper, and the health monitor down with it. Fixed.
  • Defense in depth: added a top-level process.on("unhandledRejection", ...) handler (log, don't crash) to all three services, as a last line of defense against the next unguarded async call, rather than relying on every handler being audited correctly forever.

Verified by reproducing the exact crash and confirming the fix: the same socket.io-client connection that killed the container before now completes the handshake, receives a graceful empty loaded event, and the container stays running afterward - confirmed across multiple restarts. node-pty's native binary was also confirmed functional in the process (it reached an actual chdir syscall attempt, not a module-load failure) - it only failed because /workspace doesn't exist in this ad hoc test container, which is expected outside a real pod and unrelated to the crash bug.

What's real vs. aspirational

A honest tally across all six priority tiers, since the brief specifically asked for this:

Fully implemented and verified (code review + type-checking + functional tests against fake/real dependencies, since no live Kubernetes cluster was available to test against in this environment):

  • Terminal session cleanup bug fix, with a real repro that fails on the old code and passes on the fix
  • Automatic run-on-start detection (Procfile/npm/pip)
  • Kubernetes Secret for credentials (out of the plaintext manifest)
  • JWT auth + SQLite ownership, enforced on /project, /start, and the runner's socket handshake
  • NetworkPolicy per project (with documented CNI/CIDR caveats)
  • POST /stop with final S3 sync and idempotent teardown
  • Idle-timeout auto-teardown reaper
  • Crash-loop/OOM detection, health_status tracking, GET /status, per-project status polling + frontend banner
  • Alerting webhook (the Priority 4 stretch goal)
  • Cluster capacity handling (retry-with-backoff, Unschedulable detection + rollback, clean error responses)
  • Per-user rate limiting on /project and /start
  • Namespace-per-project isolation (the Priority 5 stretch goal)
  • Configurable domains, TLS via a shared wildcard cert + cert-manager
  • Frontend deployment config (lib/config.ts) - no more hardcoded localhost backends, verified live in a dev-server session
  • Full deployment packaging for init-service/orchestrator-simple: Dockerfiles, RBAC, shared-storage manifest, Ingress - both images actually built and run in this environment, catching two real pre-existing bugs (missing .dockerignore, orchestrator-simple's broken dist/ build) that would otherwise have surfaced as a confusing production-only failure
  • A systemic unhandled-rejection crash bug across all three backend services, found by actually connecting a real socket.io-client to the runner container instead of just curling HTTP endpoints - fixed everywhere it was found, plus a top-level safety net added to all three services against the next unguarded async call

Explicitly deferred, with reasoning documented inline:

  • Pod pre-warming (Priority 3's stretch goal) - warm-pool management (claim/release, relabeling, a pre-creation loop against an empty workspace) is a meaningfully larger subsystem than anything else in this list; deferred until 1-3 were solid, per the brief's own instruction, and never circled back to given the scope already covered.
  • Queued-start pattern (Priority 5's heavier alternative to retry-with-backoff) - would need a real queue, a worker, and client-side polling for "still starting"; the brief explicitly offered retry-with-backoff as the lighter option.
  • Frontend "Stop" button - POST /stop is fully functional and tested, just not called from the UI. Small, deliberately left for whoever picks this up next since it wasn't explicitly required by any tier's task list.
  • Admin-scoped /status - there's no role/admin concept anywhere in this project's auth model, so the cluster-wide status view is available to any authenticated (anonymous) caller, not just operators. Documented as a trade-off rather than built around, since adding roles would be a real feature addition beyond what any tier asked for.

Real constraints worth knowing about, not bugs:

  • init-service and orchestrator-simple share a SQLite file on the same filesystem/host - there's no message queue or shared hosted DB, by design, for this project's scale.
  • The auth model is anonymous and device-bound (a localStorage token), not real accounts - sufficient to stop strangers from touching a replId they didn't create, not a substitute for login/signup.
  • Rate-limit and alert/teardown-history state live in memory per process - none of it survives a restart or would be shared across replicas.
  • TLS, when enabled, is cluster-wide via one shared certificate, not per-project.

License

MIT

About

Browser IDE that provisions a real, isolated Kubernetes pod per project on demand. init-service seeds the project into S3/R2; orchestrator-simple creates a Deployment/Service/Ingress via the k8s API; runner streams a live terminal (node-pty) and editor over Socket.IO; nginx-ingress routes each project by subdomain.

ephemeral-sandbox-pod-scheduler.vercel.app

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