Terraform needs the plugin directory to not be a tree of symlinks,
because it uses https://pkg.go.dev/path/filepath#Walk under the hood.
This restores some of the work that had been undone in
e7dbfd7ece
```
❯ result/bin/talosctl cluster create --wait
validating CIDR and reserving IPs
generating PKI and tokens
downloading ghcr.io/talos-systems/talos:v0.14.1
creating network talos-default
creating master nodes
creating worker nodes
renamed talosconfig context "talos-default" -> "talos-default-1"
waiting for API
bootstrapping cluster
waiting for etcd to be healthy: OK
waiting for apid to be ready: OK
waiting for kubelet to be healthy: OK
waiting for all nodes to finish boot sequence: OK
waiting for all k8s nodes to report: OK
waiting for all k8s nodes to report ready: OK
waiting for all control plane components to be ready: OK
waiting for kube-proxy to report ready: OK
waiting for coredns to report ready: OK
waiting for all k8s nodes to report schedulable: OK
merging kubeconfig into "/home/flokli/.kube/config"
PROVISIONER docker
NAME talos-default
NETWORK NAME talos-default
NETWORK CIDR 10.5.0.0/24
NETWORK GATEWAY 10.5.0.1
NETWORK MTU 1500
NODES:
NAME TYPE IP CPU RAM DISK
/talos-default-master-1 controlplane 10.5.0.2 2.00 2.1 GB -
/talos-default-worker-1 worker 10.5.0.3 2.00 2.1 GB -
```
`--provisioner qemu` was also tested. Note you need to have
`_out/{initramfs-$arch.xz,vmlinuz-$arch}` available, as documented in
their [docs](https://www.talos.dev/docs/v0.14/local-platforms/qemu/#install-talos-kernel-and-initramfs)
Now that the terraform 0.12 compatibility is not needed anymore, the
`terraform.withPlugins` and `terraform-providers.mkProvider`
implementations can be simplified.
Instead of building a bunch of bin wrappers on instantiation, the
providers are now stored in
`$out/libexec/terraform-providers/<registry>/<owner>/<name>/<version>/<os>_<arch>/terraform-provider-<name>_v<version>`
and then a simple `buildEnv` can be used to merge them.
This breaks back-compat so it's not possible to mix-and-match with
previous versions of nixpkgs. In exchange, it now becomes possible to
use the providers from
[nixpkgs-terraform-providers-bin](https://github.com/numtide/nixpkgs-terraform-providers-bin)
directly.
Remove the last provider that is not published to the registry. They
publish the provider on their own website but it's not API-compatible
with the Hashicorp registry so the update script doesn't work with it.
