feat(vm): add optional reboot_after_update configuration flag (#1777)

* feat(vm): add optional reboot after update configuration

- Add `reboot_after_update` parameter to VM resource
- Update documentation to reflect new configuration option
- Implement logic to control VM reboot after configuration changes
- Provide warning if reboot is required but disabled by configuration

---------

Signed-off-by: Pavel Boldyrev <627562+bpg@users.noreply.github.com>

docs/resources/virtual_environment_vm.md

@@ -483,7 +483,8 @@ output "ubuntu_vm_public_key" {
         - `wxp` - Windows XP.
 - `pool_id` - (Optional) The identifier for a pool to assign the virtual machine to.
 - `protection` - (Optional) Sets the protection flag of the VM. This will disable the remove VM and remove disk operations (defaults to `false`).
-- `reboot` - (Optional) Reboot the VM after initial creation. (defaults to `false`)
+- `reboot` - (Optional) Reboot the VM after initial creation (defaults to `false`).
+- `reboot_after_update` - (Optional) Reboot the VM after update if needed (defaults to `true`).
 - `rng` - (Optional) The random number generator configuration. Can only be set by `root@pam.`
     - `source` - The file on the host to gather entropy from. In most cases, `/dev/urandom` should be preferred over `/dev/random` to avoid entropy-starvation issues on the host.
     - `max_bytes` - (Optional) Maximum bytes of entropy allowed to get injected into the guest every `period` milliseconds (defaults to `1024`). Prefer a lower value when using `/dev/random` as source.

proxmoxtf/resource/vm/vm.go

@@ -42,6 +42,7 @@ import (
 
 const (
 	dvRebootAfterCreation = false
+	dvRebootAfterUpdate   = true
 	dvOnBoot              = true
 	dvACPI                = true
 	dvAgentEnabled        = false
@@ -144,6 +145,7 @@ const (
 	maxResourceVirtualEnvironmentVMNUMADevices = 8
 
 	mkRebootAfterCreation = "reboot"
+	mkRebootAfterUpdate   = "reboot_after_update"
 	mkOnBoot              = "on_boot"
 	mkBootOrder           = "boot_order"
 	mkACPI                = "acpi"
@@ -299,10 +301,16 @@ func VM() *schema.Resource {
 	s := map[string]*schema.Schema{
 		mkRebootAfterCreation: {
 			Type:        schema.TypeBool,
-			Description: "Whether to reboot vm after creation",
+			Description: "Whether to reboot VM after creation",
 			Optional:    true,
 			Default:     dvRebootAfterCreation,
 		},
+		mkRebootAfterUpdate: {
+			Type:        schema.TypeBool,
+			Description: "Whether to reboot VM after update if needed",
+			Optional:    true,
+			Default:     dvRebootAfterUpdate,
+		},
 		mkOnBoot: {
 			Type:        schema.TypeBool,
 			Description: "Start VM on Node boot",
@@ -5643,6 +5651,15 @@ func vmUpdateDiskLocationAndSize(
 
 	// Perform a regular reboot in case it's necessary and haven't already been done.
 	if reboot {
+		canReboot := d.Get(mkRebootAfterUpdate).(bool)
+		if !canReboot {
+			return []diag.Diagnostic{{
+				Severity: diag.Warning,
+				Summary: "a reboot is required to apply configuration changes, but automatic " +
+					"reboots are disabled by 'reboot_after_update = false'. Please reboot the VM manually.",
+			}}
+		}
+
 		vmStatus, err := vmAPI.GetVMStatus(ctx)
 		if err != nil {
 			return diag.FromErr(err)