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.
```release-notes
* Logging cleanups
* Updates kube-dns to use client-go 3
* Updates containers to use alpine as the base image on all platforms
* Adds support for IPv6
```
Automatic merge from submit-queue (batch tested with PRs 53106, 52193, 51250, 52449, 53861). 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>.
kube-dns-anti-affinity: kube-dns never-co-located-in-the-same-node
**What this PR does / why we need it**:
This is upstreaming the kubernetes/kops#2705 pull request by @jamesbucher that was originally against [kops](github.com/kubernetes/kops).
Please see kubernetes/kops#2705 for more details, including a lengthy discussion.
Briefly, given the constraints of how the system works today:
+ if you need multiple DNS pods primarily for availability, then requiredDuringSchedulingIgnoredDuringExecution makes sense because putting more than one DNS pod on the same node isn't useful
+ if you need multiple DNS pods primarily for performance, then
preferredDuringScheduling IgnoredDuringExecution makes sense because it will allow the DNS pods to schedule even if they can't be spread across nodes
**Which issue this PR fixes**
fixeskubernetes/kops#2693
**Release note**:
```release-note
Improve resilience by annotating kube-dns addon with podAntiAffinity to prefer scheduling on different nodes.
```
