* Run at least two replicas of CoreDNS to better support
rolling updates (previously, kube-dns had a pod nanny)
* On multi-master clusters, set the CoreDNS replica count
to match the number of masters (e.g. a 3-master cluster
previously used replicas:1, now replicas:3)
* Add AntiAffinity preferred rule to favor distributing
CoreDNS pods across controller nodes nodes
* Continue to ensure scheduler and controller-manager run
at least two replicas to support performing kubectl edits
on single-master clusters (no change)
* For multi-master clusters, set scheduler / controller-manager
replica count to the number of masters (e.g. a 3-master cluster
previously used replicas:2, now replicas:3)
* Add new bird and felix readiness checks
* Read MTU from ConfigMap veth_mtu
* Add RBAC read for serviceaccounts
* Remove invalid description from CRDs
* Adjust firewall rules, security groups, cloud load balancers,
and generated kubeconfig's
* Facilitates some future simplifications and cost reductions
* Bare-Metal users who exposed kube-apiserver on a WAN via their
router or load balancer will need to adjust its configuration.
This is uncommon, most apiserver are on LAN and/or behind VPN
so no routing infrastructure is configured with the port number
* Remove PersistentVolumeLabel admission controller flag
* Switch Deployments and DaemonSets to apps/v1
* Minor update to pod-checkpointer image version
* Add flannel service account and limited RBAC cluster role
* Change DaemonSets to tolerate NoSchedule and NoExecute taints
* Remove deprecated apiserver --etcd-quorum-read flag
* Update Calico from v3.0.1 to v3.0.2
* Add Calico GlobalNetworkSet CRD
* https://github.com/poseidon/terraform-render-bootkube/pull/44
* Allow kube-dns to respond to DNS queries with a custom
suffix, instead of the default 'cluster.local'
* Useful when multiple clusters exist on the same local
network and wish to query services on one another
* Update hyperkube from v1.8.3 to v1.8.4
* Remove flock from bootstrap-apiserver and kube-apiserver
* Remove unused critical-pod annotations in manifests
* Use service accounts for kube-proxy and pod-checkpointer
* Update Calico from v2.6.1 to v2.6.3
* Update flannel from v0.9.0 to v0.9.1
* Remove Calico termination grace period to prevent calico
from getting stuck for extended periods
* https://github.com/poseidon/terraform-render-bootkube/pull/29
* Change controllers from a managed group to individual instances
* Create discrete DNS records to each controller's private IP for etcd
* Change etcd to run on-host, across controllers (etcd-member.service)
* Reduce time to bootstrap a cluster
* Deprecate self-hosted-etcd on the Google Cloud platform
