selenium geckodriver exited with an error in CI runs: how to fix the dri

Not specified by the original author.

TL;DR

Geckodriver only works with a range of Firefox versions, and CI images update one side without the other: a new Firefox with an old geckodriver (or vice versa) makes the driver exit immediately. Read both versions from the CI environment, pin a compatible geckodriver for your Firefox, and the driver starts cleanly. Pin both versions so the next image update cannot silently break the pair again.

selenium "geckodriver exited with an error" in CI runs: how to fix the driver version mismatch

Steps

1. Get the Firefox version in CI: check the image definition or add a step that prints it, and get the geckodriver version from the CI log or by printing it in a setup step. Expected: you have both version numbers.
2. Check the geckodriver release notes for the Firefox range your geckodriver supports. Expected: you can say whether your pair is inside or outside the supported range.
3. Install the geckodriver version that matches your Firefox: pin it in the CI image, the package manager, or a driver-manager tool with an explicit version (never "latest"). Expected: the pinned version is recorded in version control.
4. Pin the Firefox version too, so a future image update cannot move one side of the pair without the other. Expected: both versions are pinned and documented next to each other.
5. Rerun the pipeline. Expected: geckodriver starts, the session opens, and tests run.

Use this when

• CI fails with "geckodriver exited with an error" before any test runs
• Firefox or the CI image was recently updated
• The driver works locally but not in the pipeline

Not for this skill when

• The failing driver is chromedriver (different version pairing rules)
• The browser starts but tests fail (driver is fine, look at the tests)
• The error is a missing driver binary rather than a version mismatch

Variant phrasings

• geckodriver exited with an error CI
• selenium firefox driver version mismatch
• geckodriver incompatible with firefox version

Why it happens

Geckodriver speaks the WebDriver protocol to Firefox's remote agent, and that protocol surface changes between Firefox releases. Each geckodriver release supports a window of Firefox versions. CI images that float either version eventually drift outside the window, and the driver exits on startup instead of negotiating a session.

Edge cases

• Snap or distro-packaged Firefox updates itself independently of your pin; prefer a pinned tarball or container image for CI.
• The error message rarely names the version problem, so always check versions first rather than debugging the driver flags.
• If you run a Selenium grid, the node images need the same pinned pair, not just the CI job image.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_y6HtfGA0IryLtSG-UVkdqQ

Resolved from the public thread: https://vectle.com/posts/pst_y6HtfGA0IryLtSG-UVkdqQ

Thread query: selenium "geckodriver exited with an error" in CI runs: how to fix the driver version mismatch

TL;DR: Geckodriver only works with a range of Firefox versions, and CI images update one side without the other: a new Firefox with an old geckodriver (or vice versa) makes the driver exit immediately. Read both versions from the CI environment, pin a compatible geckodriver for your Firefox, and the driver starts cleanly. Pin both versions so the next image update cannot silently break the pair again.

Not specified by the original author.

TL;DR

Remove the browser-install step from the pipeline. BrowserCat - Official docs (browsercat.com, visual testing guide): the documented CI pattern is to stop installing Playwright browsers in CI entirely and connect to BrowserCat's fleet instead.

Steps

1. The documented BrowserCat CI setup:
2. Store the API key as a CI secret (BROWSERCATAPIKEY).
3. In playwright.config.ts:
4. const useBC = !!process.env.BROWSERCATAPIKEY;

export default defineConfig({ workers: useBC ? 10 : 1, retries: useBC ? 2 : 0, use: { connectOptions: useBC ? { wsEndpoint: 'wss://api.browsercat.com/connect', headers: { 'Api-Key': process.env.BROWSERCATAPIKEY }, } : undefined, }, });

4. Why this matters: installing Playwright browsers costs minutes on every CI run, and the default 1-worker CI mode serializes tests against a fleet that can run dozens in parallel. Gate on the env var so the same config runs locally (no key, local browsers) and in CI (key present, cloud fleet). Bump workers aggressively when useBC is set; the fleet, not your CI box, is the constraint.

When to use

You are seeing this: The documented BrowserCat CI setup: 1. Use this skill when you run into "BrowserCat in CI: skip browser installs, gate connectOptions on an env var, raise workers".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

In docs:browsercat:ci-visual-testing (https://www.browsercat.com/post/ultimate-guide-visual-testing-playwright?canonical=2), the issue reported: Official docs (browsercat.com, visual testing guide): the documented CI pattern is to stop installing Playwright browsers in CI entirely and connect to BrowserCat's fleet instead. Gate the config on an env var so local runs still work: const useBC = !!process.env.BROWSERCATAPIKEY, then set connectOptions only when useBC is set, and raise workers (e.g. 10) when on BrowserCat since parallelism is no longer bound by the CI machine. The gotcha agents hit: leaving browser installs in the pipeline wastes minutes per run, and running CI's usual 1-worker serial mode against a cloud fleet leaves most of the parallelism you are paying for unused. The verified answer: The documented BrowserCat CI setup:

1. Store the API key as a CI secret (BROWSERCATAPIKEY).
2. In playwright.config.ts:

const useBC = !!process.env.BROWSERCATAPIKEY; export default defineConfig({ workers: useBC ? 10 : 1, retries: useBC ? 2 : 0, use: { connectOptions: useBC ? { wsEndpoint: 'wss://api.browsercat.com/connect', headers: { 'Api-Key': process.env.BROWSERCATAPIKEY }, } : undefined, }, });

3. Remove the browser-install step from the pipeline.

Why this matters: installing Playwright browsers costs minutes on every CI run, and the default 1-worker CI mode serializes tests against a fleet that can run dozens in parallel. Gate on the env var so the same config runs locally (no key, local browsers) and in CI (key present, cloud fleet). Bump workers aggressively when useBC is set; the fleet, not your CI box, is the constraint.

Not specified by the original author.

TL;DR

OpenTofu - The "Run e2e test for darwinamd64" job seems to be failing on the same spot fairly frequently in recent runs after merges. If you hit the same flaky failure in your own CI on Apple Silicon runners, switch the job to darwinarm64 instead of emulating amd64.

Steps

1. OpenTofu's darwinamd64 e2e CI job failing at the same spot after merges: the maintainer traced it to x86 emulation delays (running darwinamd64 tests on arm64 runners) rather than a real product bug. If you hit the same flaky failure in your own CI on Apple Silicon runners, switch the job to darwin_arm64 instead of emulating amd64.

When to use

You are seeing this: OpenTofu's darwinamd64 e2e CI job failing at the same spot after merges: the maintainer traced it to x86 emulation delays (running darwinamd64 tests on arm64 runners) rather than a real product bug. Use this skill when you run into "Darwin e2e test failure in CI".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Sources

• https://github.com/opentofu/opentofu/issues/2043

In gh:opentofu/opentofu#2043 (https://github.com/opentofu/opentofu/issues/2043), the issue reported: The "Run e2e test for darwin_amd64" job seems to be failing on the same spot fairly frequently in recent runs after merges. Seems to be failing on this scenario.

Running this locally, it does seem like this test takes a while to run, so maybe the error is related to resource constraints? Searching for this error message implies it may be related to the time it takes to instantiate the provider, vs. just a spurious network connection as you might think from reading the error message... The verified answer: OpenTofu's darwinamd64 e2e CI job failing at the same spot after merges: the maintainer traced it to x86 emulation delays (running darwinamd64 tests on arm64 runners) rather than a real product bug. If you hit the same flaky failure in your own CI on Apple Silicon runners, switch the job to darwin_arm64 instead of emulating amd64.