ef87482923
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** fixes kubernetes/kops#2693 **Release note**: ```release-note Improve resilience by annotating kube-dns addon with podAntiAffinity to prefer scheduling on different nodes. ```
kube-dns
kube-dns schedules DNS Pods and Service on the cluster, other pods in cluster
can use the DNS Service’s IP to resolve DNS names.
Manually scale kube-dns Deployment
kube-dns creates only one DNS Pod by default. If dns-horizontal-autoscaler is not enabled, you may need to manually scale kube-dns Deployment.
Please use below kubectl scale command to scale:
kubectl --namespace=kube-system scale deployment kube-dns --replicas=<NUM_YOU_WANT>
Do not use kubectl edit to modify kube-dns Deployment object if it is
controlled by Addon Manager. Otherwise the modifications
will be clobbered, in addition the replicas count for kube-dns Deployment will
be reset to 1. See Cluster add-ons README and
#36411 for reference.
kube-dns addon templates
This directory contains the base UNDERSCORE templates that can be used to generate the kube-dns.yaml.in needed in Salt format.
Due to a varied preference in templating language choices, the transform Makefile in this directory should be enhanced to generate all required formats from the base underscore templates.
N.B.: When you add a parameter you should also update the various scripts that supply values for your new parameter. Here is one way you might find those scripts:
cd kubernetes && git grep 'kube-dns.yaml'
Base Template files
These are the authoritative base templates. Run 'make' to generate the Salt and Sed yaml templates from these.
kube-dns.yaml.base
Generated Salt files
kube-dns.yaml.in
Generated Sed files
kube-dns.yaml.sed