Goal:

• Update CloudFormation Template responsible to create subnets[0] on installer repo to reflect the OpenShift docs updates from AWS Outposts, which introduced the two changes:
  • More three arguments for OutpostArn
  • Condition checking when it is Outpost subnet
  • "kubernetes.io/cluster/unmanaged" subnet tag

Reason:

AWS Outpost document wasn't initially providing CloudFormation template to provision subnet, which is an standard for edge zones (Local Zone and Wavelength) books[1]. The final version of AWS Outpost documentation[2] introduces the support of the same template[3] used in WL/LZ to provision subnets, with the correct statements in adoc for OpenShift Documentation repository.

The goal of this change is to keep synchronous those templates to decrease the gap between docs and UPI IaC.

The attention point is to make sure the "unmanaged" tag should not applied to anything other than Outpost subnets (condition introduced in the new template)

Acceptance criteria:

• CloudFormation template for subnets updated (PR open and merged)
• CI tests for Local Zones and Wavelength zones (edge-zones) for BYOVPC (shared-vpc) must pass
• The tag "unmanaged" is not triggered in any utilization than Outpost subnets creation

References:

[0] https://github.com/openshift/installer/blob/master/upi/aws/cloudformation/01_vpc_99_subnet.yaml 

[1] Local and Wavelength zones templates:

https://docs.openshift.com/container-platform/4.15/installing/installing_aws/installing-aws-localzone.html#installation-cloudformation-subnet-localzone_installing-aws-localzone 

https://docs.openshift.com/container-platform/4.15/installing/installing_aws/installing-aws-wavelength-zone.html#installation-cloudformation-subnet-localzone_installing-aws-wavelength-zone 

[2] AWS Outposts docs

https://docs.openshift.com/container-platform/4.15/post_installation_configuration/configuring-aws-outposts.html 

[3] Outposts template

https://docs.openshift.com/container-platform/4.15/post_installation_configuration/configuring-aws-outposts.html#installation-cloudformation-subnet-localzone_configuring-aws-outposts