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Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>. Add code and yaml for Istio as an addon This commit adds the following: - YAML for istio components to the addons directory (versions with and without auth) - logic to copy the appropriate YAML file into the addons manager dir, depending on ENABLE_ISTIO and ISTIO_AUTH_TYPE env vars - changes to addon manager script which allow plugins to exist in namespace other than kube-system. This is needed for Istio functionality - additional initialization for Istio in addon manager. This has been manually tested - e2e tests are in progress but require additional code to enable istio in tests. See: - https://github.com/istio/istio/pull/2841 - https://github.com/kubernetes/test-infra/pull/6612 **What this PR does / why we need it**: Allow [Istio](https://istio.io/) to be installed as an addon. This simplifies the Istio setup process on k8s and GKE. Istio team is trying to make it easier for end users to get to a basic functional installation. **Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*: **Special notes for your reviewer**: **Release note**: ```release-note NONE ```
Legacy Cluster add-ons
For more information on add-ons see the documentation.
Overview
Cluster add-ons are resources like Services and Deployments (with pods) that are shipped with the Kubernetes binaries and are considered an inherent part of the Kubernetes clusters.
There are currently two classes of add-ons:
- Add-ons that will be reconciled.
- Add-ons that will be created if they don't exist.
More details could be found in addon-manager/README.md.
Cooperating Horizontal / Vertical Auto-Scaling with "reconcile class addons"
"Reconcile" class addons will be periodically reconciled to the original state given
by the initial config. In order to make Horizontal / Vertical Auto-scaling functional,
the related fields in config should be left unset. More specifically, leave replicas
in ReplicationController / Deployment / ReplicaSet unset for Horizontal Scaling,
leave resources for container unset for Vertical Scaling. The periodic reconcile
won't clobbered these fields, hence they could be managed by Horizontal / Vertical
Auto-scaler.
Add-on naming
The suggested naming for most of the resources is <basename> (with no version number).
Though resources like Pod, ReplicationController and DaemonSet are exceptional.
It would be hard to update Pod because many fields in Pod are immutable. For
ReplicationController and DaemonSet, in-place update may not trigger the underlying
pods to be re-created. You probably need to change their names during update to trigger
a complete deletion and creation.