Merge pull request #3 from imjasonh/imjasonh-patch-1

container-vm/cloud-init.yaml.tftpl

@@ -0,0 +1,71 @@
+#cloud-config
+# This cloud-init configuration defines systemd services to run Docker containers
+# on Container-Optimized OS (COS) with full observability support.
+
+write_files:
+%{ for name, container in containers ~}
+  - path: /etc/systemd/system/${name}.service
+    permissions: 0644
+    owner: root
+    content: |
+      [Unit]
+      Description=Containerized application: ${name}
+      # Wait for the Docker socket to be ready
+      Wants=docker.socket
+      After=docker.service
+      
+      [Service]
+      # Crucial for persistence: ensure the service restarts on exit.
+      Restart=${container.restart_policy}
+      RestartSec=5s
+      
+      # Stop and remove any pre-existing container with the same name.
+      ExecStartPre=/usr/bin/docker stop ${name} || true
+      ExecStartPre=/usr/bin/docker rm ${name} || true
+      
+      # Pull the image before starting.
+      ExecStartPre=/usr/bin/docker pull ${container.image}
+      
+      # The main execution command: docker run.
+      # When logging is enabled, use the gcplogs driver to send container logs to Cloud Logging.
+      ExecStart=/usr/bin/docker run \
+        --name ${name} \
+%{ if enable_logging ~}
+        --log-driver=gcplogs \
+        --log-opt gcp-project=${project_id} \
+        --log-opt gcp-log-cmd=true \
+        --log-opt gcp-meta-zone=true \
+        --log-opt gcp-meta-name=true \
+        --log-opt labels=container_name \
+        --label container_name=${name} \
+%{ endif ~}
+%{ for e in container.env ~}
+        -e ${e.name}="${e.value}" \
+%{ endfor ~}
+        ${container.image} \
+%{ if container.command != "" ~}
+        "${container.command}" \
+%{ endif ~}
+%{ for arg in container.args ~}
+        # Escape single quotes: end quoted string, add escaped quote, resume quoted string
+        '${replace(arg, "'", "'\\''")}' \
+%{ endfor ~}
+
+      
+      # ExecStop is called when the service is stopped manually.
+      ExecStop=/usr/bin/docker stop ${name}
+
+      [Install]
+      WantedBy=multi-user.target
+
+%{ endfor ~}
+
+runcmd:
+  # Reload the systemd configuration to recognize the new service files.
+  - systemctl daemon-reload
+%{ for name, container in containers ~}
+  # Enable and start ${name} service.
+  - systemctl enable ${name}.service
+  - systemctl start ${name}.service
+%{ endfor ~}
+

container-vm/main.tf

@@ -0,0 +1,64 @@
+# Fetch the latest source image based on the input variables (defaulting to COS)
+data "google_compute_image" "source_image" {
+  family  = var.source_image_family
+  project = var.source_image_project
+}
+
+# Render the cloud-init YAML template using dynamic module inputs
+locals {
+  rendered_cloud_init = templatefile("${path.module}/cloud-init.yaml.tftpl", {
+    containers     = var.containers,
+    enable_logging = var.enable_logging,
+    project_id     = var.project_id,
+  })
+}
+
+# The Instance Template resource itself
+resource "google_compute_instance_template" "container_vm_template" {
+  project      = var.project_id
+  name_prefix  = "systemd-container-tmpl-"
+  description  = "Runs a container using Docker, managed by a systemd unit via cloud-init."
+  machine_type = var.machine_type
+  region       = var.region
+  labels       = var.labels
+  
+  # Disk configuration using the fetched OS image
+  disk {
+    source_image = data.google_compute_image.source_image.self_link
+    auto_delete  = true
+    boot         = true
+  }
+
+  # Network configuration (private VM - no external IP)
+  network_interface {
+    network    = var.network
+    subnetwork = var.subnetwork
+  }
+
+  # Service Account configuration (needed for Google Cloud API access, including image pulls)
+  service_account {
+    email  = var.service_account_email
+    scopes = ["cloud-platform"]
+  }
+
+  # Metadata for cloud-init and observability
+  metadata = {
+    user-data                  = local.rendered_cloud_init
+    google-logging-enabled     = tostring(var.enable_logging)
+    google-monitoring-enabled  = tostring(var.enable_monitoring)
+    cos-metrics-enabled        = tostring(var.enable_cos_metrics)
+  }
+
+  scheduling {
+    automatic_restart   = true
+    on_host_maintenance = "MIGRATE"
+  }
+
+  # Enable shielded VM features for security
+  shielded_instance_config {
+    enable_secure_boot          = true
+    enable_vtpm                 = true
+    enable_integrity_monitoring = true
+  }
+}
+

container-vm/outputs.tf

@@ -0,0 +1,10 @@
+output "instance_template_self_link" {
+  description = "The self-link of the created instance template. Use this to deploy VMs or MIGs."
+  value       = google_compute_instance_template.container_vm_template.self_link
+}
+
+output "instance_template_name" {
+  description = "The name of the created instance template."
+  value       = google_compute_instance_template.container_vm_template.name
+}
+

container-vm/variables.tf

@@ -0,0 +1,94 @@
+variable "project_id" {
+  description = "The GCP project ID."
+  type        = string
+}
+
+variable "region" {
+  description = "The region where the compute template is created."
+  type        = string
+  default     = "us-central1"
+}
+
+variable "machine_type" {
+  description = "The machine type for the VM instance template."
+  type        = string
+  default     = "e2-medium"
+}
+
+variable "containers" {
+  description = "A map of containers to run on the VM. Each key is the container name, and the value specifies the container configuration."
+  type = map(object({
+    image   = string
+    command = optional(string, "")
+    args    = optional(list(string), [])
+    env = optional(list(object({
+      name  = string
+      value = string
+    })), [])
+    restart_policy = optional(string, "always")
+  }))
+
+  validation {
+    condition     = length(var.containers) > 0
+    error_message = "At least one container must be specified."
+  }
+
+  validation {
+    condition     = alltrue([for name, c in var.containers : can(regex("^.+@sha256:[a-f0-9]{64}$", c.image))])
+    error_message = "All container images must be referenced by digest (e.g., 'gcr.io/my-project/my-app@sha256:<64 hex chars>')."
+  }
+}
+
+variable "service_account_email" {
+  description = "The email of the service account to use for the VM. Must be created outside this module."
+  type        = string
+}
+
+# Defaulting to COS, which has Docker/containerd pre-installed.
+variable "source_image_family" {
+  description = "The OS image family to use. COS is recommended."
+  type        = string
+  default     = "cos-stable"
+}
+
+variable "source_image_project" {
+  description = "The project hosting the source image."
+  type        = string
+  default     = "cos-cloud"
+}
+
+variable "network" {
+  description = "The VPC network to attach the VM to (e.g., 'projects/PROJECT/global/networks/NETWORK' or 'NETWORK')."
+  type        = string
+}
+
+variable "subnetwork" {
+  description = "The subnetwork to attach the VM to (e.g., 'projects/PROJECT/regions/REGION/subnetworks/SUBNET' or 'SUBNET')."
+  type        = string
+}
+
+# Observability variables
+variable "enable_logging" {
+  description = "Enable Cloud Logging for the VM and containers. When true, container logs are sent to Cloud Logging using the gcplogs driver."
+  type        = bool
+  default     = true
+}
+
+variable "enable_monitoring" {
+  description = "Enable Cloud Monitoring for the VM. When true, VM metrics are collected and sent to Cloud Monitoring."
+  type        = bool
+  default     = true
+}
+
+variable "enable_cos_metrics" {
+  description = "Enable Container-Optimized OS metrics collection for additional container and system metrics."
+  type        = bool
+  default     = true
+}
+
+variable "labels" {
+  description = "Labels to apply to the instance template for organization and filtering in Cloud Monitoring and Logging."
+  type        = map(string)
+  default     = {}
+}
+