NetApp Volumes: mount large-capacity volumes via Cloud DNS

[okrause]

Large-capacity volumes and FlexCache expose multiple NFS endpoint IPs. Add volume dns_config and private-zone support so clients, including Slurm, mount by FQDN and use every endpoint. Update EDA and Slurm examples plus docs.

Goal is to have a larger populations of clients spread their clients evenly (statistically) over all endpoint IPs to even out load on storage backend.

[gemini-code-assist]

Summary of Changes

Hello, 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 introduces support for mounting large-capacity NetApp volumes and FlexCache caches via Cloud DNS. By configuring a private DNS zone, clients can now mount storage using an FQDN that resolves to multiple NFS endpoint IPs in a round-robin fashion. This change addresses the limitation where clients previously only utilized a single IP address, significantly improving load distribution and performance for compute-heavy workloads like Slurm.

Highlights

• DNS-based Volume Mounting: Introduced a new dns_config parameter to the netapp-volume module, allowing volumes to be mounted via FQDN using Cloud DNS round-robin for improved performance.
• Enhanced DNS Module: Updated the dns-managed-zone module to support private visibility and multiple VPC networks, enabling secure internal DNS resolution for storage endpoints.
• New Example Blueprint: Added netapp-volumes-slurm.yaml, a new blueprint demonstrating a Slurm cluster configuration that leverages DNS-backed volume mounting.
• Documentation Updates: Updated EDA blueprints and general network storage documentation to reflect the new DNS-based mounting patterns for large-capacity volumes and FlexCache.

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[gemini-code-assist]

Code Review

This pull request introduces private Cloud DNS integration for Google Cloud NetApp Volumes and FlexCache, enabling clients to mount large-capacity volumes and caches using a single FQDN that resolves to multiple NFS endpoint IPs via DNS round-robin. It updates the EDA blueprints, adds a new Slurm example blueprint (netapp-volumes-slurm.yaml), and updates the relevant modules and documentation. Feedback on the changes suggests removing the redundant google_project_service resource for dns.googleapis.com inside the netapp-volume module to prevent potential permission conflicts and avoid requiring elevated Service Usage permissions during deployment.

[aslam-quad]

Please NOTE : We recently upgraded our repository's Go version to 1.26 (#6173). We strongly recommend rebasing your open branches onto the latest develop branch to avoid or resolve any PR test failures.

Thank you!

[okrause]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces support for mounting large-capacity Google Cloud NetApp Volumes and FlexCache caches using private Cloud DNS round-robin FQDNs, which distributes Slurm clients across multiple NFS endpoints. It updates the netapp-volume and dns-managed-zone modules, adds a new netapp-volumes-slurm example blueprint, and updates the EDA blueprints and documentation. Feedback suggests stripping the trailing dot from the generated FQDN in dns.tf using trimsuffix to prevent potential NFS client mount failures.

[okrause]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces support for mounting large-capacity Google Cloud NetApp Volumes and FlexCache caches using private Cloud DNS round-robin FQDNs, which distributes client mounts across multiple NFS endpoints in Slurm clusters. It updates the netapp-volume and dns-managed-zone modules, adds a new netapp-volumes-slurm.yaml example, and updates the EDA blueprints and documentation. Feedback on the changes highlights a potential race condition in dns.tf where downstream modules might attempt to mount the volume before the DNS record is fully active; establishing an implicit dependency on the DNS record set resource is recommended to ensure proper provisioning order.

[okrause]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces support for mounting large-capacity Google Cloud NetApp Volumes and FlexCache caches using private Cloud DNS round-robin A records, allowing Slurm clients to distribute mounts across all available NFS endpoint IPs via FQDNs. The changes update the netapp-volume and dns-managed-zone modules, add a new netapp-volumes-slurm example blueprint, and update existing EDA blueprints and documentation. Feedback on the changes suggests restricting the unix_permissions for the /home filesystem in the new blueprint from 0777 to 0755 to prevent security risks associated with world-writable home directories.

[okrause]

@agrawalkhushi18 This is ready to review.

[okrause]

I accidentally pushed other code on this branch. I reverted it back to good commit. My apologies.