Linkerd Edge Release Roundup: June 2024

Welcome to the June 2024 Edge Release Roundup post, where we dive into the most recent edge releases to help keep everyone up to date on the latest and greatest!

How to give feedback

Remember, edge releases are a snapshot of our current development work on main; by definition, they always have the most recent features but they may have incomplete features, features that end up getting rolled back later, or (like all software) even bugs. That said, edge releases are intended for production use, and go through a rigorous set of automated and manual tests before being released.

We would be delighted to hear how these releases work out for you! You can open a GitHub issue or discussion, join us on Slack, or visit the Buoyant Linkerd Forum – all are great ways to reach us.

Community contributions

We couldn’t do what we do without the Linkerd community, and this batch of releases is definitely no exception. Huge thanks to knowmost, Marwan Ahmed, and Nico Feulner for their contributions! You’ll find more information about all of these contributions in the release-by-release details below.

Recommendations and breaking changes

We recommend edge-24.5.5 for anyone considering an edge-24.5.* release; it has important fixes for the Linkerd CNI plugin on GKE. edge-24.5.1 is specifically not recommended for users of GKE, due to a bug with the default Linkerd configuration in that release.

Starting in edge-24.5.1, the patchs metric introduced in edge-24.3.4 is renamed to patches.

Finally, starting in edge-24.5.2, Linkerd will install the GRPCRoute CRD in the gateway.networking.k8s.io API group, in preparation for later GRPCRoute support. (You can disable this by setting enableHttpRoutes to false when installing, which will also prevent Linkerd from installing the HTTPRoute CRD in the gateway.networking.k8s.io API group.)

The releases

This group of releases has focused on IPv6 support - delivered in edge-24.5.2! - and finalizing fixes for some edge cases in the way Linkerd handles EndpointSlices and HTTPRoutes. Of course, each edge release has many dependency updates; we won’t list them all here, but you can find them in the release notes for each release.

edge-24.5.5 (May 31, 2024)

This release switches IPv6 off by default for the entire control plane, including the Linkerd CNI plugin. Set disableIPv6 to false to enable IPv6.

edge-24.5.4 (May 23, 2024)

We recommend edge-24.5.5 instead of this release. In this release, IPv6 support is off by default for most of the control plane, but it is mistakenly on by default for the Linkerd CNI plugin.

This release adds support for JSON output to the linkerd inject, linkerd uninject and linkerd profile commands, and a --token flag to linkerd diagnostics policy that allows specifying the context token to use so that you can see how specific clients will see policies. It also adds support for setting the group ID for the control plane (thanks, Nico Feulner!), switches IPv6 to off by default for the control plane, adds support for several proxy settings to the linkerd-control-plane chart, allows overriding how many cores control-plane components can use, correctly supports Gateway API producer routes, fixes a race conditions around EndpointSlice updates, and fixes intermittent routing failures with HTTPRoute (issue 12610).

edge-24.5.3 (May 15, 2024)

If you use the Linkerd CNI plugin on GKE, you will need to disable IPv6 or use edge-24.5.5 instead.

This release removes an internal limit on the number of concurrent gRPC streams to the control plane, leaving available memory as the only constraint.

edge-24.5.2 (May 13, 2024)

If you use the Linkerd CNI plugin on GKE, you will need to disable IPv6 or use edge-24.5.5 instead.

This release adds support for IPv6. It defaults to enabled: set disableIPv6 to true when installing to disable it. It also correctly sets the backend_not_found status on HTTPRoutes with no backends. Finally, it adds the Gateway API GRPCRoute resource (in the gateway.networking.k8s.io API group) as part of continued work on support for GRPCRoutes, although this edge release doesn’t attach any functionality to the CRD.

To prevent Linkerd from installing any CRDs into gateway.networking.k8s.io, set enableHttpRoutes to false when installing.

edge-24.5.1 (May 2, 2024)

We recommend edge-24.5.5 instead of this release due to a bug that prevents Linkerd from functioning on GKE with the default configuration. Additionally, this release has one breaking change: the patchs metric introduced in edge-24.3.4 is now correctly named patches.

This release adds configurable HTTP/2 server keepalives, fixes CLI issues and opaque-port issues when using native sidecars (issue #12395), restores Server v1beta1 to ease migrations after it was mistakenly removed in edge-24.1.2, fixes an issue that could cause the endpoints gauge to report incorrect numbers of endpoints, and continues ongoing work on upcoming IPv6 support.

Additionally, it avoids unnecessary cleanup of headless endpoint mirrors during garbage collection (thanks, Marwan Ahmed!) and cleans up some documentation in the code (thanks, knowmost!).

Installing the latest edge release

Installing the latest edge release needs just a single command.

curl --proto '=https' --tlsv1.2 -sSfL https://run.linkerd.io/install-edge | sh

You can also install edge releases with Helm.

Linkerd is for everyone

Linkerd is a graduated project of the Cloud Native Computing Foundation. Linkerd is committed to open governance. If you have feature requests, questions, or comments, we’d love to have you join our rapidly-growing community! Linkerd is hosted on GitHub, and we have a thriving community on Slack, Twitter, and in mailing lists. Come and join the fun!

Linkerd generally does new edge releases weekly; watch this space to keep up-to-date. Feedback on this blog series is welcome! Just ping @flynn on the Linkerd Slack.