feat: Add private endpoint subnetwork variable for safer cluster modules

[christiangonre]

This PR adds the option to define a private_endpoint_subnetwork value for the safer-cluster modules.

After this PR, every time you want to create a new GKE cluster it creates a new subnet in the same VPC of the GKE cluster. This PR adds the option to deploy the endpoint without creating a new subnet.

No breaking changes because the default value of the var is null, same value that we are using currently in the private_cluster module

[gemini-code-assist]

Summary of Changes

Hello @christiangonre, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the GKE safer-cluster modules by adding a new configuration option that allows users to explicitly define a subnetwork for the private endpoint. This provides more flexibility in network design and resource management, as it avoids the automatic creation of a new subnet and instead enables the use of an existing one. The change is designed to be backward-compatible, maintaining stability for current implementations.

Highlights

• New Variable for Private Endpoints: Introduced a new variable, private_endpoint_subnetwork, to the safer-cluster modules, allowing users to specify an existing subnetwork for the GKE private endpoint.
• Enhanced Network Control: This change provides greater control over network resource provisioning by enabling the use of a pre-existing subnetwork, preventing the automatic creation of a new one for the private endpoint.
• Non-Breaking Change: The new variable defaults to null, ensuring no breaking changes for existing deployments.

Changelog

• autogen/safer-cluster/main.tf.tmpl
  • Added the private_endpoint_subnetwork variable to the module "gke" configuration.
• autogen/safer-cluster/variables.tf.tmpl
  • Defined a new private_endpoint_subnetwork variable of type string with a default value of null.

Activity

• No human activity has been recorded on this pull request yet.

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[gemini-code-assist]

Code Review

This pull request introduces a private_endpoint_subnetwork variable to the safer-cluster module, allowing users to specify an existing subnetwork for the GKE cluster's private endpoint. This is a valuable addition for more flexible network configurations. I've found one potential issue where using the new variable could cause Terraform errors due to conflicting arguments. My review includes a comment with a suggested fix for this.

[apeabody]

/gemini review

[apeabody]

/gcbrun

[gemini-code-assist]

Code Review

This pull request introduces the private_endpoint_subnetwork variable to the safer-cluster modules, allowing users to specify an existing subnetwork for the GKE master's private endpoint. This is a valuable addition that avoids the automatic creation of a new subnet. The implementation is sound and consistently applied across the autogen templates and the generated modules. I've suggested some minor documentation improvements to clarify the relationship between the new variable and master_ipv4_cidr_block for better user experience.

[apeabody]

/gcbrun

[apeabody]

/gemini review

[gemini-code-assist]

Code Review

This pull request adds the private_endpoint_subnetwork variable to the safer-cluster and safer-cluster-update-variant modules, allowing users to specify an existing subnetwork for the GKE private endpoint. The implementation correctly nullifies master_ipv4_cidr_block when private_endpoint_subnetwork is used, respecting their mutual exclusivity. All relevant files, including autogen templates, module code, documentation, and metadata, have been updated consistently. The change is non-breaking as the new variable defaults to null.

[apeabody]

/gcbrun

[apeabody]

Thanks for the contribution @christiangonre