* 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
* 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
* Create separate container-linux-install profiles (and
cached-container-linux-install) for each node in a cluster
* Fix contention bug on bare-metal during `terraform apply`.
With only a global install profile, terraform would create
(or retain) the profile for each cluster and try to delete
it for each cluster being deleted. As a result, in some cases
apply had to be run multiple times before terraform's repr
of constraints was satisfied (profile deleted and recreated)
* Allow Container Linux install properties to vary between
clusters, such as using a different Container Linux channel
or version for different clusters
* Template bare-metal Container Linux configs with Terraform's
(limited) template_file module. This allows rendering problems
to be identified during `terraform plan` and is favored over
using the Matchbox templating feature when the configs are
served to PXE booting nodes.
* Writes a Matchbox profile for each machine, which will be served
as-is. The effect is the same, each node gets provisioned with its
own Container Linux config.
