This is a Terraform module for deploying a production-grade HashiCorp Vault cluster on Google Compute Engine (GCE). It provisions all necessary networking (VPC, subnets, NAT, firewalls), a GCS bucket for Vault's storage backend, a KMS key for auto-unseal and TLS encryption, and manages the full lifecycle of Vault nodes via a managed instance group with autoscaling and autohealing. The module supports both internal and external load balancers, and includes an optional submodule (`modules/cluster`) for organizations that need to separate concerns (e.g., shared VPC setups). The core logic resides in the `modules/cluster` submodule, which contains instance templates, load balancer configuration, health checks, IAM bindings, and self-signed TLS certificate generation. A startup script template handles Vault installation, configuration, mTLS setup, logging agents, and security hardening (core dumps disabled, swap disabled, unprivileged user). The module is highly parameterized with ~60 input variables, allowing customization of machine types, Vault versions, networking, and TLS management. It is designed for high availability (HA) with GCS backend and auto-unseal via Cloud KMS. The repository includes examples, integration tests using Kitchen/Terraform and Inspec, and CI/CD pipelines, indicating a mature, community-maintained module. The code is clean and follows Google's Cloud Foundation Toolkit conventions, but it is relatively conventional Terraform infrastructure code, not particularly novel or reusable beyond its intended purpose.