k3s/pkg/apis
Kubernetes Submit Queue 3bc575c91f Merge pull request #33550 from rtreffer/kubelet-allow-multiple-dns-server
Automatic merge from submit-queue

Allow multipe DNS servers as comma-seperated argument for kubelet --dns

This PR explores how kubectls "--dns" could be extended to specify multiple DNS servers for in-cluster PODs. Testing on the local libvirt-coreos cluster shows that multiple DNS server are injected without issues.

Specifying multiple DNS servers increases resilience against
- Packet drops
- Single server failure

I am debugging services that do 50+ DNS requests for a single incoming interactive request, thus highly increase the chance of a slowdown (+5s) due to a single packet drop. Switching to two DNS servers will reduce the impact of the issues (roughly +1s on glibc, 0s on musl, error-rate goes down to error-rate^2).

Note that there is no need to change any runtime related code as far as I know. In the case of "default" dns the /etc/resolv.conf is parsed and multiple DNS server are send to the backend anyway. This only adds the same capability for the clusterFirst case.

I've heard from @thockin that multiple DNS entries are somehow considered. I've no idea what was considered, though. This is what I would like to see for our production use, though.

```release-note
NONE
```
2017-02-15 12:45:32 -08:00
..
abac mechanical repercussions 2017-01-13 08:27:14 -05:00
apps move metav1 conversions to metav1 2017-02-14 11:47:23 -05:00
authentication install authentication.k8s.io/v1, add tests 2017-02-07 01:44:56 -05:00
authorization install authorization.k8s.io/v1, add tests 2017-02-06 18:16:51 -05:00
autoscaling Generated Files for autoscaling/v2alpha1 2017-02-07 22:25:27 -05:00
batch Avoid closing over range variables 2017-02-06 16:02:21 +01:00
certificates Add custom conversion funcs not directly into pkg/api.Scheme 2017-02-05 15:01:47 +01:00
componentconfig Merge pull request #33550 from rtreffer/kubelet-allow-multiple-dns-server 2017-02-15 12:45:32 -08:00
extensions move metav1 conversions to metav1 2017-02-14 11:47:23 -05:00
imagepolicy Update protobufs 2017-02-02 06:58:29 +01:00
meta/v1 genericapiserver: get rid of pkg/genericapiserver/server/openapi/common 2017-01-19 13:06:47 +01:00
policy Update protobufs 2017-02-02 06:58:29 +01:00
rbac Reconcile bootstrap clusterroles on server start 2017-02-14 12:33:05 -05:00
storage Update protobufs 2017-02-02 06:58:29 +01:00
OWNERS Updated top level owners file to match new format 2017-01-19 11:29:16 -08:00