OSDOCS-10892 adding install config params for aws subnets

[bscott-rh]

Version(s):
4.19

Issue:
https://issues.redhat.com/browse/OSDOCS-10892

Link to docs preview:

QE review:

• QE has approved this change.

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[tthvo]

Nice! I just have some comments :D

[tthvo]

Suggested change

	|Defines a list of existing subnets to be used in place of automatically generated subnets. You specify a subnet by providing the subnet ID and a list of roles that apply to that subnet. If you specify subnet IDs but do not specify roles for any subnet, the subnets' roles will be decided automatically. If you do not specify any roles, you must ensure that any other subnets in your VPC have the `kubernetes.io/cluster/<cluster-id>` or `kubernetes.io/cluster/unmanaged: true` tags, or the installation will fail.
	|A list of subnets in an existing VPC to be used in place of automatically created subnets. You specify a subnet by providing the subnet ID and an optional list of roles that apply to that subnet. If you specify subnet IDs but do not specify roles for any subnet, the subnets' roles will be decided automatically. If you do not specify any roles, you must ensure that any other subnets in your VPC have the `kubernetes.io/cluster/.*: .*` or `kubernetes.io/cluster/unmanaged: true` tags.
	The subnets must be part of the same `machineNetwork[].cidr` ranges that you specify.
	For a standard cluster, specify a public and a private subnet for each availability zone.
	For a private cluster, specify a private subnet for each availability zone.
	For clusters that use AWS Local Zones, you must add AWS Local Zone subnets to this list to ensure edge machine pool creation.

Other than some nit on wordings. I want to verify the suggestions a bit:

• Subnets' roles are optional -> should make it clear
• kubernetes.io/cluster/<cluster-id> is actually just a tag key. A complete tag consists of key and value (for example, kubernetes.io/cluster/my-cluster: owned). So, I suggest the use of .*, similar to here. But maybe you have a better alternative 😄
• The notes about requirements for public/private and edge zone are still valid and should keep them. Though, we can reword.

[tthvo]

Suggested change

	|One or more roles that apply to the subnet specified by `platform.aws.vpc.subnets.id`. If you specify a role for any subnet, each subnet must have at least one assigned role, and the "ClusterNode", "IngressControllerLB", "ControlPlaneExternalLB", and "ControlPlaneInternalLB" roles must be assigned to at least one subnet. However, if the cluster scope is internal, then the "ControlPlaneExternalLB" role is not required.
	|One or more roles that apply to the subnet specified by `platform.aws.vpc.subnets.id`. If you specify a role for any subnet, each subnet must have at least one assigned role, and the `ClusterNode`, `BootstrapNode`, `IngressControllerLB`, `ControlPlaneExternalLB`, and `ControlPlaneInternalLB` roles must be assigned to at least one subnet. However, if the cluster scope is internal, then the `ControlPlaneExternalLB` role is not required.
	For subnets in AWS Local Zones, only `EdgeNode` role can be assigned.

Verification:

• BootstrapNode is also a required role if subnet roles are specified. See EP (note: we change it to BootstrapNode instead of Bootstrap).
• EdgeNode is exclusive for subnets in AWS Local/Wavelength zones and must be specified if such subnets are included.
• Use backticks for code-like 😅 similar to this doc, maybe?

[tthvo]

Suggested change

	|List of one or more role types. Valid values include "ClusterNode", "EdgeNode", "Bootstrap", "IngressControllerLB", "ControlPlaneExternalLB", and "ControlPlaneInternalLB".
	|List of one or more role types. Valid values include `ClusterNode`, `EdgeNode`, `BootstrapNode`, `IngressControllerLB`, `ControlPlaneExternalLB`, and `ControlPlaneInternalLB`.

BootstrapNode is the right one (i.e. we divert a bit from the EP which says Bootstrap)

[tthvo]

platform:
  aws:
    vpc:
      subnets:
        - id: subnet-<id1>
        - id: subnet-<id2>
        - id: subnet-<id3>

I suggest we can keep it simple by giving an example of specifying subnets without roles here.

• It is same as before but following new field convention.
• Since there is no explanation of such subnet roles here, it's best not to make it complex. And roles are optional also.
• Side note: There is no ControlPlaneLB role btw :D You might see it somewhere because we are lazy to say/type ControlPlaneExternal and ControlPlaneInternalLB haha

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[tthvo]

/lgtm

Looks good to me! I'd leave it to others to have another look and approve :D

[tthvo]

/cc @yunjiang29

[yunjiang29]

/lgtm

[skopacz1]

Just a few nits, otherwise lgtm!

[skopacz1]

This needs an Oxford comma here:

Suggested change

|One or more roles that apply to the subnet specified by `platform.aws.vpc.subnets.id`. If you specify a role for any subnet, each subnet must have at least one assigned role, and the `ClusterNode`, `IngressControllerLB`, `ControlPlaneExternalLB`, `BootstrapNode` and `ControlPlaneInternalLB` roles must be assigned to at least one subnet. However, if the cluster scope is internal, then the `ControlPlaneExternalLB` role is not required.

|One or more roles that apply to the subnet specified by `platform.aws.vpc.subnets.id`. If you specify a role for any subnet, each subnet must have at least one assigned role, and the `ClusterNode`, `IngressControllerLB`, `ControlPlaneExternalLB`, `BootstrapNode`, and `ControlPlaneInternalLB` roles must be assigned to at least one subnet. However, if the cluster scope is internal, then the `ControlPlaneExternalLB` role is not required.

[skopacz1]

Idk if this would look better or worse, but maybe an underscore between ID and the numbers?

Suggested change

	- id: subnet-<id1>
	- id: subnet-<id2>
	- id: subnet-<id3>
	- id: subnet-<id_1>
	- id: subnet-<id_2>
	- id: subnet-<id_3>

Up to you