* 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.
* 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.
* 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
