Brad Fitzpatrick
7dcb378875
The natlab-integrationtest CI job frequently flakes by exhausting its 3m go test timeout. The root cause is that the QEMU VMs run under pure software emulation (TCG) with no KVM. Under TCG, the guest kernel's timer calibration busy-loops are at the mercy of host CPU scheduling. When two VMs boot simultaneously on a 2-core CI runner, one VM's calibration gets starved and produces wrong results, leaving the kernel with broken timers that prevent it from ever completing boot — even after the other VM finishes and frees up CPU. Additionally, the microvm machine type doesn't provide HPET hardware, but the kernel command line specified clocksource=hpet. And the VM image build (make natlab) ran inside the test itself, consuming most of the 3m timeout budget before the actual test started. Fix by: - Enabling KVM when /dev/kvm is available, so timer calibration uses real hardware timers unaffected by host CPU scheduling. - Adding a CI step to set /dev/kvm permissions on the GitHub Actions runner (ubuntu-latest provides KVM but needs a udev rule). - Pre-building the VM image in a separate CI step so it doesn't cut into the go test -timeout budget. - Replacing the hardcoded 60s context timeout with one derived from t.Deadline(), so the test uses the full -timeout budget. - Adding VM boot progress detection (AwaitFirstPacket) and QMP diagnostics, so boot failures produce clear errors instead of opaque "context deadline exceeded" messages. With KVM enabled, the test passes reliably even on a single CPU core with 3 parallel workers — a scenario that was 100% broken under TCG. Fixes #18906 Change-Id: I4c87631a9c9678d185b9f30cb05c0f7bfa9f5c62 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Tailscale
Private WireGuard® networks made easy
Overview
This repository contains the majority of Tailscale's open source code.
Notably, it includes the tailscaled daemon and
the tailscale CLI tool. The tailscaled daemon runs on Linux, Windows,
macOS, and to varying degrees
on FreeBSD and OpenBSD. The Tailscale iOS and Android apps use this repo's
code, but this repo doesn't contain the mobile GUI code.
Other Tailscale repos of note:
- the Android app is at https://github.com/tailscale/tailscale-android
- the Synology package is at https://github.com/tailscale/tailscale-synology
- the QNAP package is at https://github.com/tailscale/tailscale-qpkg
- the Chocolatey packaging is at https://github.com/tailscale/tailscale-chocolatey
For background on which parts of Tailscale are open source and why, see https://tailscale.com/opensource/.
Using
We serve packages for a variety of distros and platforms at https://pkgs.tailscale.com.
Other clients
The macOS, iOS, and Windows clients use the code in this repository but additionally include small GUI wrappers. The GUI wrappers on non-open source platforms are themselves not open source.
Building
We always require the latest Go release, currently Go 1.26. (While we build releases with our Go fork, its use is not required.)
go install tailscale.com/cmd/tailscale{,d}
If you're packaging Tailscale for distribution, use build_dist.sh
instead, to burn commit IDs and version info into the binaries:
./build_dist.sh tailscale.com/cmd/tailscale
./build_dist.sh tailscale.com/cmd/tailscaled
If your distro has conventions that preclude the use of
build_dist.sh, please do the equivalent of what it does in your
distro's way, so that bug reports contain useful version information.
Bugs
Please file any issues about this code or the hosted service on the issue tracker.
Contributing
PRs welcome! But please file bugs. Commit messages should reference bugs.
We require Developer Certificate of
Origin
Signed-off-by lines in commits.
See commit-messages.md (or skim git log) for our commit message style.
About Us
Tailscale is primarily developed by the people at https://github.com/orgs/tailscale/people. For other contributors, see:
- https://github.com/tailscale/tailscale/graphs/contributors
- https://github.com/tailscale/tailscale-android/graphs/contributors
Legal
WireGuard is a registered trademark of Jason A. Donenfeld.