* Choose the Container Linux derivative Flatcar Linux on
bare-metal by setting os_channel to flatcar-stable, flatcar-beta
or flatcar-alpha
* As with Container Linux from Red Hat, the version (os_version)
must correspond to the channel being used
* Thank you to @dongsupark from Kinvolk
* Terraform v0.11.4 introduced changes to remote-exec
that mean Typhoon bare-metal clusters require multiple
runs of terraform apply to ssh and bootstrap.
* Bare-metal installs PXE boot a live instance to install
to disk and then reboot from disk as controllers/workers.
Terraform remote-exec has no way to "know" to wait until
the reboot has occurred to kickoff Kubernetes bootstrap.
Previously Typhoon created a "debug" user during this
install phase to allow an admin to SSH, but remote-exec
would hang, trying to connect as user "core". Terraform
v0.11.4 changes this behavior so remote-exec fails and
a user must re-run terraform apply until succeeding.
* A new way to "trick" remote-exec into waiting for the
reboot into the disk install is to run SSH on a non-standard
port during the disk install. This retains the ability
for an admin to SSH during install (most distros don't have
this) and fixes the issue so only a single run of terraform
apply is needed.
* https://github.com/hashicorp/terraform/pull/17359#issuecomment-376415464
* Use etcd v3.3 --listen-metrics-urls to expose only metrics
data via http://0.0.0.0:2381 on controllers
* Add Prometheus discovery for etcd peers on controller nodes
* Temporarily drop two noisy Prometheus alerts
* Add a node-role.kubernetes.io/controller="true" node label
to controllers so Prometheus service discovery can filter to
services that only run on controllers (i.e. masters)
* Leave node-role.kubernetes.io/master="" untouched as its
a Kubernetes convention
* 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
* When restarting masters, `etcd-member.service` may fail to lookup peers if
/etc/resolv.conf hasn't been populated yet. Require the wait-for-dns.service.
