629dc311b4
Previously there was a mismatch between how nodes store AUMs and what the control plane would offer during sync: - Client compaction: Nodes aggressively compact their TKA state -- they keep the last 24 AUMs, every AUM received in the last two weeks, and then everything from there back to the last checkpoint. Depending on when it compacts, a node may only have ~50 AUMs. - Exponential sampling: To save bandwidth, the control plane would send a SyncOffer containing ancestors at exponentially increasing intervals (4th, 16th, 64th, 256th...). If a node has been offline for too long, the exponential sampling skips the node's smaller window. When the SyncOffer and local state are disjoint, the node cannot find a common ancestor to use for synchronisation. It enters a failure loop where it keeps polling for new TKA state, but it cannot catch up and has an increasingly-outdated view of the tailnet. This patch replaces the exponential sampling with a SyncOffer that sends every checkpoint ancestor of the current HEAD. Since every node is guaranteed to keep at least one checkpoint after compaction, we're more likely to have an intersection for the sync process. This patch also increases `maxSyncHeadIntersectionIter`, which in practice means the control plane will send every checkpoint in the current chain. This means all affected nodes will be able to find an intersection and catch up immediately, without requiring a client update. It's still possible for a node to be unable to sync, but these edge cases become less likely with this change. (For example, if a node is 1000+ AUMs behind, or if it creates a local branch and then compacts away the intersection with the main chain.) This patch includes a regression test with synthetic data, and I verified the fix with customer data. Updates https://github.com/tailscale/corp/issues/40404 Change-Id: I2174011bb23a2b5972f6d1591aadcc016e3cba35 Signed-off-by: Alex Chan <alexc@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.