This release introduces direct pod-to-pod multicluster service mirroring. When
clusters are deployed on a flat network, Linkerd can export multicluster
services in a way where cross-cluster traffic does not need to go through the
gateway. This enhances multicluster authentication and can reduce the need for
provisioning public load balancers.
In addition, this release adds support for the
[Gateway API](https://gateway-api.sigs.k8s.io/) HTTPRoute resource (in the
`gateway.networking.k8s.io` api group). This improves compatibility with other
tools that use these resources such as [Flagger](https://flagger.app/) and
[Argo Rollouts](https://argoproj.github.io/rollouts/). The release also includes
a large number of features and improvements to HTTPRoute including the ability
to set timeouts and the ability to define consumer-namespace HTTPRoutes.
Finally, this release includes a number of bugfixes, performance improvements,
and other smaller additions.
**Upgrade notes**: Please see the
[upgrade instructions](https://linkerd.io/2/tasks/upgrade/#upgrade-notice-stable-2140).
* Multicluster
* Remove namespace field from cluster scoped resources to fix pruning
* Added -o json flag for the `linkerd multicluster gateways` command (thanks
@hiteshwani29)
* Introduced `logFormat` value to the multicluster `Link` Helm Chart (thanks
@bunnybilou!)
* Added leader-election capabilities to the service-mirror controller
* Added high-availability (HA) mode for the multicluster service-mirror
* Added a new `remoteDiscoverySelector` field to the multicluster `Link` CRD,
which enables a service mirroring mode where the control plane
performs discovery for the mirrored service from the remote cluster, rather
than creating Endpoints for the mirrored service in the source cluster
* HTTPRoute
* Fixed `linkerd uninstall` issue for HTTPRoute
* Added support for `gateway.networking.k8s.io` HTTPRoutes in the policy
controller
* Added support for RequestHeaderModifier and RequestRedirect HTTP filters in
outbound policy; filters may be added at the route or backend level
* Added support for the `ResponseHeaderModifier` HTTPRoute filter
* Added support for HTTPRoutes defined in the consumer namespace
* Added support for HTTPRoute `parent_refs` that do not specify a port
* CRDs
* Patched the MeshTLSAuthentication CRD to force providing at least one
identity/identityRef
* Control Plane
* Send Opaque protocol hint for opaque ports in destination controller
* Replaced deprecated `failure-domain.beta.kubernetes.io/zone` labels in Helm
charts with `topology.kubernetes.io/zone` labels (thanks @piyushsingariya!)
* Replaced `server_port_subscribers` Destination controller gauge metric with
`server_port_subscribes` and `server_port_unsubscribes` counter metrics
* Proxy
* Handle Opaque protocol hints on endpoints
* Added `outbound_http_balancer_endpoints` metric
* Fixed missing route_ metrics for requests with ServiceProfiles
* Fixed proxy startup failure when using the `config.linkerd.io/admin-port`
annotation (thanks @jclegras!)
* Added distinguishable version information to proxy logs and metrics
* CLI
* The `linkerd diagnostics policy` command now displays outbound policy when
the target resource is a Service
* A fix for HA validation checks when Linkerd is installed with Helm. Thanks
@mikutas!!
* Viz
* Add the `kubelet` NetworkAuthentication back since it is used by the
`linkerd viz allow-scrapes` subcommand.
* Fixed the `linkerd viz check` command so that it will wait until the viz
extension becomes ready
* Fixed an issue where specifying a `remote_write` config would cause the
Prometheus config to be invalid (thanks @hiteshwani29)
* Improved validation of the `--to` and `--from` flags for the `linkerd viz stat`
command (thanks @pranoyk)
* Added `-o jsonpath` flag to `linkerd viz tap` to allow filtering output fields
(thanks @hiteshwani29!)
* Fixed a Grafana error caused by an incorrect datasource (thanks @albundy83!)
* Fixed missing "Services" menu item in the Spanish localization for the
`linkerd-viz` web dashboard (thanks @mclavel!)
* Extensions
* Added missing label `linkerd.io/extension` to certain resources to ensure they
pruned when appropriate (thanks @ClementRepo)
* Added tolerations and nodeSelector support in extensions `namespace-metadata`
Jobs (thanks @pssalman!)
* Init Containers
* Added an option for disabling the network validator's security context for
environments that provide their own
* CNI
* Added --set flag to install-cni plugin (thanks @amit-62!)
* Fixed missing resource-cni labels on linkerd-cni, this blocked the
linkerd-cni pods from coming up when the injector was broken (thanks
@migueleliasweb!)
* Build
* Build improvements for multi-arch build artifacts. Thanks @MarkSRobinson!!
This release includes changes from a massive list of contributors! A special
thank-you to everyone who helped make this release possible:
* Amir Karimi @AMK9978
* Amit Kumar @amit-62
* Andre Marcelo-Tanner @kzap
* Andrew @andrew-gropyus
* Arnaud Beun @bunnybilou
* Clement @proxfly
* Dima @krabradosty
* Grégoire Bellon-Gervais @albundy83
* Harsh Soni @harsh020
* Jean-Charles Legras @jclegras
* Loong Dai @daixiang0
* Mark Robinson @MarkSRobinson
* Miguel Elias dos Santos @migueleliasweb
* Pranoy Kumar Kundu @pranoyk
* Ryan Hristovski @ryanhristovski
* Takumi Sue @mikutas
* Zakhar Bessarab @zekker6
* hiteshwani29 @hiteshwani29
* pheianox
* pssalman @pssalman