feat(vm): add install_guest_agent to inject qemu-guest-agent via cloud-init

[jniedergang]

Related Issue

harvester/harvester#10141

Description

Add install_guest_agent boolean field to the harvester_virtualmachine resource that injects the qemu-guest-agent package and service enablement into cloud-init user_data, matching the Harvester UI "Install Guest Agent" checkbox behavior.

Changes

• Add install_guest_agent schema field (bool, default false)
• Add InstallGuestAgent field to Constructor, processed before CloudInit
• Inject cloud-init snippet (package_update, packages, runcmd) into user_data when:
  • install_guest_agent = true
  • user_data_base64 and user_data_secret_name are not set
  • qemu-guest-agent is not already present in user_data
• Import by detecting qemu-guest-agent in cloud-init volume UserData
• Regenerate docs with make generate

Example

resource "harvester_virtualmachine" "example" {
  # ...
  install_guest_agent = true

  cloudinit {
    user_data = "#cloud-config\nuser: sles\n"
  }
}

The guest agent snippet is appended to the existing user_data.

Test plan

• Unit tests: go test ./pkg/importer/ -run TestInstallGuestAgent — pass
• go build ./... — compilation passes
• gofmt -l . — no formatting issues
• go generate ./... — docs generated
• Functional test on Harvester v1.7.1:
  • Created VM with install_guest_agent = true — verified cloud-init user_data contains qemu-guest-agent package and systemctl enable --now qemu-guest-agent runcmd
  • Idempotence: terraform plan shows 0 changes
  • Toggle to install_guest_agent = false — cloud-init snippet removed
  • terraform destroy — VM cleaned up