* Heapster can now get nodes (i.e. kubelets) from the apiserver and
source metrics from the Kubelet authenticated API (10250) instead of
the Kubelet HTTP read-only API (10255)
* https://github.com/kubernetes/heapster/blob/master/docs/source-configuration.md
* Use the heapster service account token via Kubelet bearer token
authn/authz.
* Permit Heapster to skip CA verification. The CA cert does not contain
IP SANs and cannot since nodes get random IPs that aren't known upfront.
Heapster obtains the node list from the apiserver, so the risk of
spoofing a node is limited. For the same reason, Prometheus scrapes
must skip CA verification for scraping Kubelet's provided by the apiserver.
* https://github.com/poseidon/typhoon/blob/v1.12.1/addons/prometheus/config.yaml#L68
* Create a heapster ClusterRole to work around the default Kubernetes
`system:heapster` ClusterRole lacking the proper GET `nodes/stats`
access. See https://github.com/kubernetes/heapster/issues/1936
* Support bare-metal cached_install=true mode with Flatcar Linux
where assets are fetched from the Matchbox assets cache instead
of from the upstream Flatcar download server
* Skipped in original Flatcar support to keep it simple
https://github.com/poseidon/typhoon/pull/209
* 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)
* Require a terraform-provider-digitalocean plugin version of
1.0 or higher within the same major version (e.g. allow 1.1 but
not 2.0)
* Change requirement from ~> 0.1.2 (which allowed up to but not
including 1.0 release)
* If using --enable-ssl-passthrough or exposing TCP/UDP services,
be aware of https://github.com/kubernetes/ingress-nginx/pull/3038
* Workarounds until the fix merges are to stay on 0.17.1, use the
suggested development image, or revert to securityContext
`runAsNonRoot: false` for a while (less secure)
* Fix issue where worker nodes didn't delete themselves on
scale-down or deallocation (e.g. low priority instances).
Lowercase the hostname and delete the Kubernetes node
* Kubelet registers the lowercase hostname as the node name,
but Azure workers get hostname CLUSTER-worker-GENERATED where
the generated identifier may contain uppercase characters
* Add new bird and felix readiness checks
* Read MTU from ConfigMap veth_mtu
* Add RBAC read for serviceaccounts
* Remove invalid description from CRDs
* Broaden internal-etcd firewall rule to allow etcd client
traffic (2379) from other controller nodes
* Previously, kube-apiservers were only able to connect to their
node's local etcd peer. While master node outages were tolerated,
reaching a healthy peer took longer than neccessary in some cases
* Reduce time needed to bootstrap a cluster
* Typhoon for Fedora Atomic uses system containers, container
images containing metadata, but built directly from upstream
and published and serve through Quay.io
* https://github.com/poseidon/system-containers
* Remove controller_networkds and worker_networkds variables. These
variables were always listed as experimental, unsupported, and excluded
from documentation in anticipation of Container Linux Config snippets
* Use Container Linux Config snippets on bare-metal instead. They
provide safer, more powerful, and more elegant host customization
