Change notes for edge-20.7.5

[alpeb]

edge-20.7.5

This edge brings a new approach to multicluster service mirror controllers and
the way services in target clusters are selected for mirroring.

The long-awaited Bring-Your-Own-Prometheus case has been finally addressed.

Many other improvements from our great contributors are described below. Also
note progress is still made under the covers for future support for Service
Topologies (by @Matei207) and delivering image builds in multiple platforms (by
@aliariff).

• Multicluster
  • Replaced the single service-mirror controller, with separate controllers
    that will be installed per target cluster through linkerd multicluster link. More info here.
  • Changed 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. More
    info here.
  • Added new section in the dashboard for exposing multicluster gateway metrics
    (thanks @tharun208!)
• Prometheus
  • Added global.prometheusUrl to the Helm config to have linkerd use a
    different external Prometheus instance instead of the one provided by
    default.
  • Added ability to declare sidecar containers in the Prometheus Helm config.
    This allows adding components allowing things like exporting logs to
    services such as Cloudwatch, Stackdriver, Datadog, etc. (thanks @memory!)
  • Upgraded Prometheus to the latest version (v2.19.3), which should consume
    substantially less memory, among other benefits.
• Other
  • Fixed bug in linkerd check that was failing to wait for Prometheus to be
    available right after having installed linkerd.
  • Added ability to set priorityClassName for CNI DaemonSet pods, and to
    install CNI in an existing namespace (both options provided through the CLI
    and as Helm configs) (thanks @alex-berger!)
  • Added support for overriding the proxy's inbound and outbout TCP connection
    timeouts (thanks @mmiller1!)
  • Added library support for dashboard i18n. Strings still need to be tagged
    and translations to be added. More info
    here.
  • In some Helm charts, replace the non-standard
    linkerd.io/helm-release-version annotation with checksum/config for
    forcing restarting the component during upgrades (thanks @naseemkullah!)
  • Upgraded the proxy init-container to v1.3.4, which comes with an updated
    debian-buster distro and will provide cleaner logs listing the iptables
    rules applied.

[kleimkuhler]

Big edge! Looks good