* Drop support for `cluster_domain_suffix` customization and
always use `cluster.local`. Many components in the Kubernetes
ecosystem assume this default suffix and its very rare to be
setting a special value here these days
* Cleanup a few variables that are seldom used
* On platforms that support ARM64 instances, configure controller
and worker node host architectures separately
* For example, you can run arm64 controllers and amd64 workers
* Add `controller_arch` and `worker_arch` variables
* Remove `arch` variable
* Add `controller_disk_type`, `controller_disk_size`, and `controller_disk_iops`
variables
* Add `worker_disk_type`, `worker_disk_size`, and `worker_disk_iops` variables
and fix propagation to worker nodes
* Remove `disk_type`, `disk_size`, and `disk_iops` variables
* Add `controller_cpu_credits` and `worker_cpu_credits` variables to set CPU
pricing mode for burstable instance types
* Previously: Typhoon provisions clusters with kube-system components
like CoreDNS, kube-proxy, and a chosen CNI provider (among flannel,
Calico, or Cilium) pre-installed. This is convenient since clusters
come with "batteries included". But it also means upgrading these
components is generally done in lock-step, by upgrading to a new
Typhoon / Kubernetes release
* It can be valuable to manage these components with a separate
plan/apply process or through automations and deploy systems. For
example, this allows managing CoreDNS separately from the cluster's
lifecycle.
* These "components" will continue to be pre-installed by default,
but a new `components` variable allows them to be disabled and
managed as "addons", components you apply after cluster creation
and manage on a rolling basis. For some of these, we may provide
Terraform modules to aide in managing these components.
```
module "cluster" {
# defaults
components = {
enable = true
coredns = {
enable = true
}
kube_proxy = {
enable = true
}
# Only the CNI set in var.networking will be installed
flannel = {
enable = true
}
calico = {
enable = true
}
cilium = {
enable = true
}
}
}
```
An earlier variable `install_container_networking = true/false` has
been removed, since it can now be achieved with this more extensible
and general components mechanism by setting the chosen networking
provider enable field to false.
* Add firewall or security riles to allow node-to-node traffic
on ports 9962-9965 for Cilium and Hubble metrics. Cilium runs
with host network, so these require cloud firewall changes
* Allow for more minimal base cluster setups, that manage CoreDNS or
kube-proxy as applications, with rolling updates, or deploy systems.
Or in the case of kube-proxy, its becoming more common to not install
it and instead use Cilium
* Add a `components` pass-through variable to configure pre-installed
components like kube-proxy and CoreDNS. These components can be
disabled (individually or together) to allow for managing components
with separate plan/apply processes or automations
* terraform-render-bootstrap manifest assets are now structured as
manifests/{coredns,kube-proxy,network} so adapt the controller
layout scripts accordingly
* This is similar to some changes in v1.29.2 that allowed for the
container networking provider manifests to be skipped
Related: https://github.com/poseidon/typhoon/pull/1419, https://github.com/poseidon/typhoon/pull/1421
* When `true`, the chosen container `networking` provider is installed during cluster bootstrap
* Set `false` to self-manage the container networking provider. This allows flannel, Calico, or Cilium
to be managed via Terraform (like any other Kubernetes resources). Nodes will be NotReady until you
apply the self-managed container networking provider. This may become the default in future.
* Set CNI networking to "none" to skip installing any CNI provider
(i.e. no flannel, Calico, or Cilium). In this mode, cluster nodes
will be NotReady until you add your own CNI stack
* Motivation: I now tend to manage CNI components as addon modules
just like other applications overlaid onto a cluster. It allows for
faster iteration and may eventually become the recommendation
* AWS has recently started defaulting launch templates to IMDSv2
being "required". aws_launch_template is supposed to default to
"optional" but it doesn't.
* Requiring IMDSv2 sessions breaks a number of applications which
don't use AWS SDKs and were never meant to be complex applications
(e.g. shell scripts and the like)
* With Cilium v1.14, Cilium's kube-proxy partial mode changed to
either be enabled or disabled (not partial). This somtimes leaves
Cilium (and the host) unable to reach the kube-apiserver via the
in-cluster Kubernetes Service IP, until the host is rebooted
* As a workaround, configure Cilium to rely on external DNS resolvers
to find the IP address of the apiserver. This is less portable
and less "clean" than using in-cluster discovery, but also what
Cilium wants users to do. Revert this when the upstream issue
https://github.com/cilium/cilium/issues/27982 is resolved
* aws provider v5.0+ works alright and should be permitted,
relax the version constraint for the Typhoon AWS kubernetes
module and worker module for Fedora CoreOS and Flatcar Linux
