b651ed5ea7
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>. Bump to etcd 3.1.12 to pick up critical fix etcd [3.1.12](https://github.com/coreos/etcd/releases/tag/v3.1.12) (as well as 3.2.17 and 3.3.2) was released yesterday to fix a bug critical to kubernetes: Fix [mvcc "unsynced" watcher restore operation](https://github.com/coreos/etcd/pull/9297). - "unsynced" watcher is watcher that needs to be in sync with events that have happened. - That is, "unsynced" watcher is the slow watcher that was requested on old revision. - "unsynced" watcher restore operation was not correctly populating its underlying watcher group. - Which possibly causes [missing events from "unsynced" watchers](https://github.com/coreos/etcd/issues/9086). This will be backported to 1.9 as well. Release note: ```release-note Upgrade the default etcd server version to 3.1.12 to pick up critical etcd "mvcc "unsynced" watcher restore operation" fix. ``` cc @gyuho @wojtek-t @shyamjvs @timothysc @jdumars
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.