Skip to main content

​
Sim runners

A simulation test is any test that needs a 3D physics world to evaluate the system under test. Roboticks supports Gazebo Harmonic and Webots today, on hosted G4dn.xlarge Spot Fleet GPUs or self-hosted via the roboticks-runner binary on your own GPU box.
Sim minutes are the only meaningful cost dimension on the platform. They exist because GPU time is expensive. Reserve sim tests for the cases where headless ROS2 won’t do.

​
When is a sim test worth it

The default should be headless ROS2. Push the sim envelope only when the headless test would lie.

​
Mark the test

Two parameters on @requires_sim:
  • engine: "gazebo" or "webots". The scheduler refuses to dispatch a gazebo test to a webots runner.
  • gpu: When True, routes to G4dn.xlarge Spot Fleet (hosted) or any self-hosted runner labelled gpu=true. When False, the scheduler can use a CPU-only sim runner for lightweight scenarios.
See decorator reference for the full signature.

​
The job router

Routing priority:
  1. Self-hosted pools with matching labels take precedence (free of sim-minute charges).
  2. Hosted pools take the rest. Sim minutes are metered per the pricing page.
  3. If neither pool can serve the request, the job queues with a warning the dashboard surfaces immediately.
You set the policy at the project level: Settings → Runners → Routing. Default is “prefer self-hosted; fall back to hosted with consent”.

​
Hosted sim runners

Cold-start ranges from 30 s (Fargate cached image) to 90 s (Spot Fleet cold scale-up). Image pull and spin-up are not billed — only wall-clock the job runs.

​
Self-hosted sim runners

Run the Go binary, declare your GPU, and you’re in the pool. See Runners → Installation for the full setup. The relevant excerpt for sim:
The runner reports nvidia-smi output on enrolment; the scheduler uses it to match gpu=True jobs to physical GPUs.

​
Cost realism

A typical hosted Gazebo nav test is 60–120 s of wall-clock per run. A nightly suite of 50 such tests, running every weekday, on the Team tier (500 minutes included):
  • 50 tests × 90 s = 75 min / night.
  • 20 weekdays × 75 min = 1,500 min / month.
  • 1,500 − 500 (included) = 1,000 metered minutes.
  • 1,000 × 0.10=∗∗0.10 = **100 / month overage** on a single team running this cadence.
The self-hosted path pays the GPU once and runs free. The hosted path pays per-minute and amortises across no one. Pick deliberately.

​
Image customisation

Hosted images are pinned. If you need a customised Gazebo world or extra apt packages, two options:
  1. Bundle in your test tree. The runner makes tests/sim_assets/ available to launched worlds. Best for project-specific worlds.
  2. Bring your own image on a self-hosted runner. The runner pulls the image you point it at, including your custom Gazebo or Webots build.
Hosted custom images land in Enterprise via a managed image registry.

​
Next

Runners overview

Hosted vs self-hosted, pools, labels, autoscaling.

Self-host a runner

Get a GPU box into the pool.

Pricing

How sim minutes are counted.

Launch testing

Multi-node sim test patterns.