Tolerate flannel running on master nodes

[andrewrynhard]

DaemonSets now respect taints. This PR adds a tolerance that allows flannel to run nodes tainted with dedicated=master:NoSchedule

[philips]

Where is this taint documented?

[andrewrynhard]

Docs on this taint seem to be non-existant. I believe due to the fact that it is an alpha feature? I have been informed that kubernetes/kubeadm#150 should change this and move to beta.

[aveshagarwal]

Not sure which release this change targeted to, but in 1.6, tolerations are going to be api fields kubernetes/kubernetes#38957, and the pr is already merged.

[philips]

@andrewrynhard @aveshagarwal would one of you please email https://groups.google.com/forum/#!forum/kubernetes-sig-cluster-lifecycle and https://groups.google.com/forum/#!forum/kubernetes-sig-networking discussing this issue?

Thanks!

[davidopp]

Moving taints and tolerations from annotations to fields was announced in these messages on kubernetes-dev

https://groups.google.com/d/msg/kubernetes-dev/-fwfHQtm9GE/H1TU4yqiBAAJ
https://groups.google.com/d/msg/kubernetes-dev/Xq7MI0CvRlc/-4sM_VKtAAAJ

(and there were identical corresponding messages on kubernetes-users).

[davidopp]

The fact that some deployment environments automatically add a taint to the master node (and therefore pods that want to run on the master node need to tolerate the taint) is outside the scope of the feature itself but I can see how it might be confusing people.

[tomdee]

Tested on kubeadm with the 1.6 beta-4 - so merging.