## stable-2.9.0
This release extends Linkerd's zero-config mutual TLS (mTLS) support to all TCP
connections, allowing Linkerd to transparently encrypt and authenticate all TCP
connections in the cluster the moment it's installed. It also adds ARM support,
introduces a new multi-core proxy runtime for higher throughput, adds support
for Kubernetes service topologies, and lots, lots more, as described below:
* Proxy
* Performed internal improvements for lower latencies under high concurrency
* Reduced performance impact of logging, especially when the `debug` or
`trace` log levels are disabled
* Improved error handling for DNS errors encountered when discovering control
plane addresses; this can be common during installation before all
components have been started, allowing linkerd to continue to operate
normally in HA during node outages
* Control Plane
* Added support for [topology-aware service
routing](https://kubernetes.io/docs/concepts/services-networking/service-topology/)
to the Destination controller; when providing service discovery updates to
proxies the Destination controller will now filter endpoints based on the
service's topology preferences
* Added support for the new Kubernetes
[EndpointSlice](https://kubernetes.io/docs/concepts/services-networking/endpoint-slices/)
resource to the Destination controller; Linkerd can be installed with
`--enable-endpoint-slices` flag to use this resource rather than the
Endpoints API in clusters where this new API is supported
* Dashboard
* Added new Spanish translations (please help us translate into your
language!)
* Added new section for exposing multicluster gateway metrics
* CLI
* Renamed the `--addon-config` flag to `--config` to clarify this flag can be
used to set any Helm value
* Added fish shell completions to the `linkerd` command
* Multicluster
* Replaced the single `service-mirror` controller with separate controllers
that will be installed per target cluster through `linkerd multicluster
link`
* Changed the mechanism for mirroring services: instead of relying on
annotations on the target services, now the source cluster should specify
which services from the target cluster should be exported by using a label
selector
* Added support for creating multiple service accounts when installing
multicluster with Helm to allow more granular revocation
* Added a multicluster `unlink` command for removing multicluster links
* Prometheus
* Moved Linkerd's bundled Prometheus into an add-on (enabled by default); this
makes the Linkerd Prometheus more configurable, gives it a separate upgrade
lifecycle from the rest of the control plane, and allows users to
disable the bundled Prometheus instance
* The long-awaited Bring-Your-Own-Prometheus case has been finally addressed:
added `global.prometheusUrl` to the Helm config to have linkerd use an
external Prometheus instance instead of the one provided by default
* Added an option to persist data to a volume instead of memory, so that
historical metrics are available when Prometheus is restarted
* The helm chart can now configure persistent storage and limits
* Other
* Added a new `linkerd.io/inject: ingress` annotation and accompanying
`--ingress` flag to the `inject` command, to configure the proxy to support
service profiles and enable per-route metrics and traffic splits for HTTP
ingress controllers
* Changed the type of the injector and tap API secrets to `kubernetes.io/tls`
so they can be provisioned by cert-manager
* Changed default docker image repository to `ghcr.io` from `gcr.io`; **Users
who pull the images into private repositories should take note of this
change**
* Introduced support for authenticated docker registries
* Simplified the way that Linkerd stores its configuration; configuration is
now stored as Helm values in the `linkerd-config` ConfigMap
* Added support for Helm configuration of per-component proxy resources
requests
This release includes changes from a massive list of contributors. A special
thank-you to everyone who helped make this release possible: [Abereham G
Wodajie](https://github.com/Abrishges), [Alexander
Berger](https://github.com/alex-berger), [Ali
Ariff](https://github.com/aliariff), [Arthur Silva
Sens](https://github.com/ArthurSens), [Chris
Campbell](https://github.com/campbel), [Daniel
Lang](https://github.com/mavrick), [David Tyler](https://github.com/DaveTCode),
[Desmond Ho](https://github.com/DesmondH0), [Dominik
Münch](https://github.com/muenchdo), [George
Garces](https://github.com/jgarces21), [Herrmann
Hinz](https://github.com/HerrmannHinz), [Hu Shuai](https://github.com/hs0210),
[Jeffrey N. Davis](https://github.com/penland365), [Joakim
Roubert](https://github.com/joakimr-axis), [Josh
Soref](https://github.com/jsoref), [Lutz Behnke](https://github.com/cypherfox),
[MaT1g3R](https://github.com/MaT1g3R), [Marcus Vaal](https://github.com/mvaal),
[Markus](https://github.com/mbettsteller), [Matei
David](https://github.com/mateiidavid), [Matt
Miller](https://github.com/mmiller1), [Mayank
Shah](https://github.com/mayankshah1607),
[Naseem](https://github.com/naseemkullah), [Nil](https://github.com/c-n-c),
[OlivierB](https://github.com/olivierboudet), [Olukayode
Bankole](https://github.com/rbankole), [Paul
Balogh](https://github.com/javaducky), [Rajat
Jindal](https://github.com/rajatjindal), [Raphael
Taylor-Davies](https://github.com/tustvold), [Simon
Weald](https://github.com/glitchcrab), [Steve
Gray](https://github.com/steve-gray), [Suraj
Deshmukh](https://github.com/surajssd), [Tharun
Rajendran](https://github.com/tharun208), [Wei Lun](https://github.com/WLun001),
[Zhou Hao](https://github.com/zhouhao3), [ZouYu](https://github.com/Hellcatlk),
[aimbot31](https://github.com/aimbot31),
[iohenkies](https://github.com/iohenkies), [memory](https://github.com/memory),
and [tbsoares](https://github.com/tbsoares)