K6 Knowledge Patch

Grafana k6 Knowledge Patch

Use this skill when writing, reviewing, upgrading, or operating Grafana k6 tests. Inspect the project's pinned k6 version before applying version-specific advice. Prefer the project's manifests, scripts, configuration, and observed behavior when they disagree with generic guidance.

Reference index

Breaking changes and migration traps

Treat a v2 upgrade as an explicit migration

Before moving to k6 v2, search code and automation for all of the following:

• Go imports beginning with go.k6.io/k6/; change them to go.k6.io/k6/v2/.
• The externally-controlled executor and the pause, resume, scale, or status CLI commands; replace the executor rather than looking for renamed commands.
• Positional k6 cloud script.js, top-level k6 login, --upload-only, and options.ext.loadimpact; use explicit Cloud subcommands and options.cloud.
• K6_BINARY_PROVISIONING, K6_ENABLE_COMMUNITY_EXTENSIONS, and K6_OTEL_SINGLE_COUNTER_FOR_RATE; remove them.
• The legacy loadimpact/config.json path; move or regenerate the file under the k6 configuration directory.
• Automation that assumes the HTTP API listens by default or that an aborted Cloud run exits successfully. Enable the API with --address; treat exit status 97 as failure.

See Migration and Compatibility for extension JSON changes, archive metadata, Docker tags, and the complete migration checklist.

Migrate deprecated summary settings

Use --summary-mode=disabled or K6_SUMMARY_MODE=disabled instead of --no-summary or K6_NO_SUMMARY. Do not build new tooling around the legacy summary mode; choose compact or full. If handleSummary() legitimately needs longer than its default budget, set handleSummaryTimeout or K6_HANDLE_SUMMARY_TIMEOUT.

Use stable module paths

• Use k6/websockets, not k6/experimental/websockets.
• Use the official Redis extension instead of k6/experimental/redis.
• Use --out opentelemetry; the experimental-opentelemetry alias and K6_OTEL_EXPORTER_TYPE are deprecated.
• Replace browser FID thresholds and integrations with INP.

High-value workflows

Run JavaScript or TypeScript directly

k6 executes .ts files directly, so a separate transpilation stage is not required for supported TypeScript syntax:

import http from 'k6/http';

interface Target { url: string }
const target: Target = { url: 'https://quickpizza.grafana.com/' };

export default function () {
  http.get(target.url);
}

k6 run script.ts

Coordinate browser waits with their trigger

Arm request or response waits at the same time as the action so fast network events cannot be missed:

const [response] = await Promise.all([
  page.waitForResponse(/\/api\/.*\.json$/),
  page.click('button[data-testid="load-data"]'),
]);

Use page.route() to abort, modify, or fulfill matching requests. Remove a specific route with the identical matcher passed to page.unroute(), or clear all routes with page.unrouteAll(). For nested iframes, chain frameLocator() calls rather than manually switching frame context.

Resolve extensions automatically

Use static ES module imports so k6 can detect and provision extensions:

import dns from 'k6/x/dns';

Dynamic CommonJS require() is not discovered. If CommonJS is unavoidable, put a directive at the beginning of each relevant file, after only an optional shebang, whitespace, or comments:

"use k6 with k6/x/redis"
const redis = require('k6/x/redis');

Inspect dependencies with k6 deps --json script.js. Supply missing constraints through K6_DEPENDENCIES_MANIFEST; use k6 x to discover or run extension subcommands.

Configure Cloud context explicitly

Prefer explicit Cloud commands:

k6 cloud login --token "$MY_TOKEN" --stack my-stack-slug
k6 cloud run script.js
k6 cloud upload script.js
k6 cloud project list --format=json
k6 cloud test list --json

Cloud project resolution can come from an explicit project ID, environment or script configuration, or the configured stack's default project. For local Cloud execution, decide explicitly whether secrets and logs should leave the machine; behavior differs between maintained major lines and newer commands provide --no-cloud-logs.

Inspect and enable features

List lifecycle information with k6 features or k6 features --json. Enable features with repeated or comma-separated --features, K6_FEATURES, or the features key in config.json:

k6 run --features native-histograms,merge-run-tags script.js

Feature selections are tagged in metrics and preserved in archives and Cloud workers. native-histograms changes trend storage; merge-run-tags changes tag precedence; freeze-env makes mutation of __ENV fail in strict mode.

Operational guardrails

Make scenario overrides visible

Passing --vus N now replaces configured scenarios with a shared-iterations scenario containing N VUs and N iterations, and emits a warning. Treat the flag as a scenario override, not a harmless default.

Interpret exits and explicit failures correctly

Status consumers can distinguish a run marked by execution.test.fail() with ExecutionStatusMarkedAsFailed. In Cloud automation, preserve the distinct exit meanings: successful runs use 0, Cloud aborts use 97, and threshold aborts use 99.

Keep sensitive output deliberate

Locally executed Cloud tests can stream logs to their Cloud run. Use --no-cloud-logs when logs must remain local, and otherwise rely on Grafana secrets management and redaction for values that might be logged. Anonymous extension usage reporting can be disabled with --no-usage-report.

Pin infrastructure assumptions

Container images run as numeric UID 12345, which is useful in Kubernetes security contexts. Pin explicit Docker tags when reproducibility matters; floating :vN tags track a major line, while prereleases and maintenance releases from older majors do not update :latest.

Check output compatibility

• Rate exports use one counter labeled zero or nonzero; the old OpenTelemetry fallback is gone in v2.
• Experimental OpenTelemetry and Prometheus outputs began with a TLS 1.3 default. Prometheus remote write can set its floor with K6_PROMETHEUS_RW_TLS_MIN_VERSION.
• Cloud output v2 reports Gauge min and max in their correct fields.
• OpenTelemetry HTTP Basic Auth uses the dedicated username and password environment variables or output-config keys.

Consult the topic references before changing browser synchronization, extension provisioning, Cloud local execution, or exported metric schemas; those areas have version-sensitive behavior that is easy to misapply.