3586986416
This is the 2nd attempt. The previous was reverted while we figured out the regional mirrors (oops). New plan: k8s.gcr.io is a read-only facade that auto-detects your source region (us, eu, or asia for now) and pulls from the closest. To publish an image, push k8s-staging.gcr.io and it will be synced to the regionals automatically (similar to today). For now the staging is an alias to gcr.io/google_containers (the legacy URL). When we move off of google-owned projects (working on it), then we just do a one-time sync, and change the google-internal config, and nobody outside should notice. We can, in parallel, change the auto-sync into a manual sync - send a PR to "promote" something from staging, and a bot activates it. Nice and visible, easy to keep track of.
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.