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dmacvicar / terraform-provider-libvirt

Terraform provider to provision infrastructure with Linux's KVM using libvirt
Apache License 2.0
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Add multi-hosts support. #909

Closed gxben closed 2 years ago

gxben commented 2 years ago

This allows specifying multiple hosts (and so associated libvirt connections) to the same provider and tagging them by region and/or availability zones. This way, it becomes possible to iterate resources over multiple libvirt instances as Terraform does not yet support iteration over providers.

dmacvicar commented 2 years ago

Sorry. I don't feel comfortable with this PR. I never heard the concept of Availability Zone and Region in libvirt.

What does this solve vs https://www.terraform.io/docs/language/providers/configuration.html#alias-multiple-provider-configurations

gxben commented 2 years ago

There's no such thing as AZ or Region in libvirt indeed. The thing is that libvirt only provides host-level control and has no top-layer orchestration layer that would allow control of a cluster of libvirt hosts. This PR somehow simulates this concept and comes as a workaround to have multiple libvirt hosts detailed in a single libvirt provider, because TF doesn't allow to iterate over provider.

So, let's imagine the following scenario: you have multiple libvirt hosts in multiple datacenters or locations and you want to create VMs in each having some kind of host-affinity of high-availability. The only way currently offered by Terraform is to copy/paste your VMs TF configuration for each libvirt provider (regardless of the use of aliases) which is just nuts.

So this PR allows for having a single codebase that one can use for_each to target multiple libvirt hosts within a single provider.

dmacvicar commented 2 years ago

Thanks for the PR, but to me this introduces concepts which are alien to both libvirt and terraform and do not belong in the terraform provider layer and I don't feel like maintaining this complexity.

Not sure how to implement something like this, perhaps a libvirt API proxy?