* To accompany the restructure of the bare-metal modules to
allow discrete workers to be defined and attached to a cluster
(#1295), the `workers` variable (older way, used for defining
homogeneous workers inline) should be optional and default
to an empty list
* Add docs covering inline vs discrete metal workers
Fix#1301
* Kinvolk now publishes Flatcar Linux images for ARM64
* For now, amd64 image must specify a plan while arm64 images
must NOT specify a plan due to how Kinvolk publishes.
Rel: https://github.com/flatcar/Flatcar/issues/872
* Switch from Azure Hypervisor generation 1 to generation 2
* Change default Azure `worker_type` from Standard_DS1_v2 to Standard_D2as_v5
* Get 2 VCPU, 7 GiB, 12500Mbps (vs 1 VCPU, 3.5GiB, 750 Mbps)
* Small increase in pay-as-you-go price ($53.29 -> $62.78)
* Small increase in spot price ($5.64/mo -> $7.37/mo)
* Change from Intel to AMD EPYC (`D2as_v5` cheaper than `D2s_v5`)
Notes: Azure makes you accept terms for each plan:
```
az vm image terms accept --publish kinvolk --offer flatcar-container-linux-free --plan stable-gen2
```
Rel:
* https://learn.microsoft.com/en-us/azure/virtual-machines/dasv5-dadsv5-series#dasv5-series
* https://learn.microsoft.com/en-us/azure/virtual-machines/dv2-dsv2-series#dsv2-series
* Typhoon now consistently uses Butane Configs for snippets
(variant `fcos` or `flatcar`). Previously snippets were either
Butane Configs (on FCOS) or Container Linux Configs (on Flatcar)
* Update docs on uploading Flatcar Linux DigitalOcean images
* Update docs on uploading Fedora CoreOS Azure images
* Change subnet references to source and destinations prefixes
(plural)
* Remove references to a resource group in some load balancing
components, which no longer require it (inferred)
* Rename `worker_address_prefix` output to `worker_address_prefixes`
* Cilium (v1.8) was added to Typhoon in v1.18.5 in June 2020
and its become more impressive since then. Its currently the
leading CNI provider choice.
* Calico has grown complex, has lots of CRDs, masks its
management complexity with an operator (which we won't use),
doesn't provide multi-arch images, and hasn't been compatible
with Kubernetes v1.23 (with ipvs) for several releases.
* Both have CNCF conformance quirks (flannel used for conformance),
but that's not the main factor in choosing the default
* Use the official Kinvolk Flatcar Linux image on Google Cloud
* Change `os_image` from a custom image name to `flatcar-stable`
(default), `flatcar-beta`, or `flatcar-alpha` (**action required**)
* Change `os_image` from a required to an optional variable
* Promote Typhoon on Flatcar Linux / Google Cloud to stable
* Remove docs about needing to upload a Flatcar Linux image
manually on Google Cloud and drop support for custom images
* Add `arch` variable to Flatcar Linux AWS `kubernetes` and
`workers` modules. Accept `amd64` (default) or `arm64` to support
native arm64/aarch64 clusters or mixed/hybrid clusters with arm64
workers
* Requires `flannel` or `cilium` CNI
Similar to https://github.com/poseidon/typhoon/pull/875
