# Se Grid Configurator

> Configures Selenium Grid 4 (hub-and-node or standalone, including Docker) and wires RemoteWebDriver for parallel and distributed runs. Use when an SDET says "set up Selenium Grid", "run my tests on a remote grid", "dockerize Selenium Grid 4", "point my tests at RemoteWebDriver", or wants parallel execution across nodes. Produces config and code the engineer must run and validate in their environment.

- Skill: `pramoddutta/se-grid-configurator` (Agent Skill)
- Install (CLI): `npx skillmds@latest add pramoddutta/se-grid-configurator`
- Raw SKILL.md: https://api.skillmd.com/api/skills/pramoddutta/se-grid-configurator/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- License: MIT
- Author: PramodDutta (https://skillmd.com/u/pramoddutta)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/pramoddutta/se-grid-configurator

---


# Selenium Grid Configurator

You **stand up Selenium Grid 4 and connect tests via RemoteWebDriver**. All config
is a draft the engineer must review and run in their own environment — you cannot
see their network, ports, host resources, or security controls. Default to a
loopback-only endpoint and an internal Docker network.

## When to use
- Someone wants distributed/parallel execution across browsers or machines.
- A local test suite must be pointed at a remote grid endpoint.
- Someone asks to "dockerize the grid" or "add nodes for Chrome and Firefox".

## Workflow
1. **Pick a topology**: standalone (single JVM, quickest), hub-and-node (classic
   distributed), or fully distributed (router/distributor/sessions) for scale.
2. **Choose the runtime**: local JARs (`selenium-server-<v>.jar`) or Docker via
   `docker-compose` with `selenium/hub` + `selenium/node-chrome`/`node-firefox`.
   Require a reviewed, mutually compatible Selenium version and immutable dated
   image tag or digest; never bake a remembered version into a generated config.
   For single-host Compose, keep event-bus ports 4442/4443 on its internal service
   network. For nodes on different hosts, expose only the ports the documented
   topology requires on an approved private interface, firewalled to authorized nodes.
3. **Authorize suite execution**: confirm an approved non-production application
   target, synthetic owned identity/data, allowed side effects, cleanup/reset behavior,
   finite session/request limits, concurrency, and abort conditions. Grid network
   approval does not authorize the tests that will run through it.
4. **Set grid endpoint & capacity**: bind the UI/WebDriver port to loopback by
   default (`127.0.0.1:4444`) and use `http://localhost:4444` locally. Set
   `SE_NODE_MAX_SESSIONS` and `--max-sessions` for parallelism.
5. **Wire RemoteWebDriver** in the test with `browserName`/`browserVersion` options,
   pointing at the hub `/wd/hub` (or root in Grid 4) URL — parameterize the URL by env var.
6. **Enable only approved parallelism** in TestNG; start serially and increase
   `thread-count` only within the reviewed target, data, cleanup, and capacity budget.
7. **Emit** compose file + Java, document the network boundary and access controls,
   then stop for explicit human network/security and execution review before use.

## Output shape
```yaml
# docker-compose.yml — Selenium Grid 4 (hub + chrome/firefox nodes)
services:
  selenium-hub:
    image: ${SELENIUM_HUB_IMAGE:?set reviewed immutable hub image reference}
    # Publish only the UI/WebDriver endpoint, and only on host loopback.
    # Event-bus ports 4442/4443 remain reachable only between Compose services.
    ports: ["127.0.0.1:4444:4444"]
  chrome:
    image: ${SELENIUM_CHROME_IMAGE:?set reviewed immutable node image reference}
    depends_on: [selenium-hub]
    environment:
      - SE_EVENT_BUS_HOST=selenium-hub
      - SE_EVENT_BUS_PUBLISH_PORT=4442
      - SE_EVENT_BUS_SUBSCRIBE_PORT=4443
      - SE_NODE_MAX_SESSIONS=${GRID_MAX_SESSIONS:?set approved session ceiling}
```
```java
// RemoteWebDriver pointed at the grid (parameterize the URL by env var)
String gridUrl = System.getProperty("gridUrl", "http://localhost:4444");
ChromeOptions options = new ChromeOptions();
WebDriver driver = new RemoteWebDriver(new URL(gridUrl), options);
// Start serially; use only the human-approved TestNG concurrency/session ceiling.
```

## Guardrails
- This config is a **draft the engineer must run and validate** — ports, image tags, and host capacity are environment-specific.
- For single-host Compose, do not publish event-bus ports 4442/4443. A reviewed
  multi-host topology may expose them only on a private interface, firewalled to the
  authorized nodes and protected with the documented registration secret and transport
  controls. Bind port 4444 to loopback by default; never expose a Grid directly to the
  public internet.
- Remote access is allowed only on an explicitly approved private/trusted network
  with authentication, TLS, least-privilege network access controls, and monitoring
  supplied by a reviewed gateway or equivalent control.
- Stop before deployment or remote enablement and require an explicit human
  network/security review of interfaces, routes, firewall rules, authentication,
  TLS, users, and exposure. Also require execution approval for application target,
  test identity/data, effects, cleanup, session/request limits, concurrency, and aborts.
  Do not treat generated config as deployment or test-execution approval.
- **Never assume a locator exists** in any example test; keep tests locator-agnostic and let the engineer supply real selectors.
- Require reviewed full image references (prefer dated tags plus digests) for a mutually
  compatible Selenium release; never fabricate a version, use a stale baked-in example,
  or use `:latest`. Record the resolved references in the review evidence.
- Size `thread-count` and `SE_NODE_MAX_SESSIONS` to real node CPU/RAM; over-subscription causes flakiness, not speed.
- Never fan tests through the Grid against production, shared identities, or unowned data;
  stop on unexpected external effects, cleanup failure, or budget breach.
- Don't hardcode the hub URL in tests — parameterize by env var/system property for CI portability.
- Always `driver.quit()` remote sessions so grid slots are released.