feature(lxc): enable root disk resize without recreate. recreate container if mount points are added, deleted or changed in size

proxmox/nodes/containers/containers.go

@@ -370,3 +370,13 @@ func (c *Client) WaitForContainerConfigUnlock(ctx context.Context, ignoreErrorRe
 
 	return nil
 }
+
+// Resize Disk
+func (c *Client) ResizeContainerDisk(ctx context.Context, d *ResizeRequestBody) error {
+	err := c.DoRequest(ctx, http.MethodPut, c.ExpandPath("resize"), d, nil)
+	if err != nil {
+		return fmt.Errorf("error resize disk: %w", err)
+	}
+
+	return nil
+}

proxmox/nodes/containers/containers_types.go

@@ -275,6 +275,11 @@ type ShutdownRequestBody struct {
 	Timeout   *int              `json:"timeout,omitempty"   url:"timeout,omitempty"`
 }
 
+type ResizeRequestBody struct {
+	Disk string `json:"disk" url:"disk"`
+	Size string `json:"size" url:"size"`
+}
+
 // UpdateRequestBody contains the data for an user update request.
 type UpdateRequestBody CreateRequestBody
 

proxmoxtf/resource/container/container.go

@@ -11,6 +11,7 @@ import (
 	"errors"
 	"fmt"
 	"regexp"
+	"slices"
 	"sort"
 	"strconv"
 	"strings"
@@ -333,7 +334,7 @@ func Container() *schema.Resource {
 				Type:        schema.TypeList,
 				Description: "The disks",
 				Optional:    true,
-				ForceNew:    true,
+				ForceNew:    false,
 				DefaultFunc: func() (interface{}, error) {
 					return []interface{}{
 						map[string]interface{}{
@@ -374,7 +375,7 @@ func Container() *schema.Resource {
 							Type:             schema.TypeInt,
 							Description:      "The rootfs size in gigabytes",
 							Optional:         true,
-							ForceNew:         true,
+							ForceNew:         false,
 							Default:          dvDiskSize,
 							ValidateDiagFunc: validation.ToDiagFunc(validation.IntAtLeast(0)),
 						},
@@ -1765,7 +1766,7 @@ func containerCreateCustom(ctx context.Context, d *schema.ResourceData, m interf
 	}
 
 	diskSize := diskBlock[mkDiskSize].(int)
-	if diskDatastoreID != "" && (diskSize != dvDiskSize || len(mountPoints) > 0) {
+	if diskDatastoreID != "" && (diskSize != dvDiskSize || len(mountPoints) > 0 || len(diskMountOptions) > 0) {
 		// This is a special case where the rootfs size is set to a non-default value at creation time.
 		// see https://pve.proxmox.com/pve-docs/chapter-pct.html#_storage_backed_mount_points
 		rootFS = &containers.CustomRootFS{
@@ -2985,17 +2986,42 @@ func containerUpdate(ctx context.Context, d *schema.ResourceData, m interface{})
 		}
 
 		rootFS := &containers.CustomRootFS{}
-		// Disk ID for the rootfs is always 0
-		diskID := 0
-		vmID := d.Get(mkVMID).(int)
-		rootFS.Volume = diskBlock[mkDiskDatastoreID].(string)
-		rootFS.Volume = getContainerDiskVolume(rootFS.Volume, vmID, diskID)
+		containerConfig, e := containerAPI.GetContainer(ctx)
+		if e != nil {
+			if errors.Is(e, api.ErrResourceDoesNotExist) {
+				d.SetId("")
+				return nil
+			}
+			return diag.FromErr(e)
+		}
+
+		if containerConfig.RootFS == nil {
+			return diag.Errorf("RootFS information of container malformed.")
+		}
+		rootFS.Volume = containerConfig.RootFS.Volume
 
 		acl := types.CustomBool(diskBlock[mkDiskACL].(bool))
 		mountOptions := diskBlock[mkDiskMountOptions].([]interface{})
 		quota := types.CustomBool(diskBlock[mkDiskQuota].(bool))
 		replicate := types.CustomBool(diskBlock[mkDiskReplicate].(bool))
+
+		oldSize := containerConfig.RootFS.Size
 		size := types.DiskSizeFromGigabytes(int64(diskBlock[mkDiskSize].(int)))
+		if *oldSize > *size {
+			// TODO: we should never reach this point. The `plan` should recreate the container, not update it.
+			d.SetId("")
+			return diag.Errorf("New disk size (%s) has to be greater the current disk (%s)!", oldSize, size)
+		}
+
+		if oldSize != size {
+			e = containerAPI.ResizeContainerDisk(ctx, &containers.ResizeRequestBody{
+				Disk: "rootfs",
+				Size: size.String(),
+			})
+			if e != nil {
+				return diag.FromErr(err)
+			}
+		}
 
 		rootFS.ACL = &acl
 		rootFS.Quota = &quota
@@ -3005,15 +3031,22 @@ func containerUpdate(ctx context.Context, d *schema.ResourceData, m interface{})
 		mountOptionsStrings := make([]string, 0, len(mountOptions))
 
 		for _, option := range mountOptions {
-			mountOptionsStrings = append(mountOptionsStrings, option.(string))
+			optionString := option.(string)
+			mountOptionsStrings = append(mountOptionsStrings, optionString)
 		}
-
 		// Always set, including empty, to allow clearing mount options
 		rootFS.MountOptions = &mountOptionsStrings
 
-		updateBody.RootFS = rootFS
+		// To compare contents regardless of order, we can sort them.
+		// The schema already uses a suppress func for order, so we should be consistent.
+		sort.Strings(mountOptionsStrings)
+		currentMountOptions := containerConfig.RootFS.MountOptions
+		sort.Strings(*currentMountOptions)
+		if !slices.Equal(mountOptionsStrings, *currentMountOptions) {
+			rebootRequired = true
+		}
 
-		rebootRequired = true
+		updateBody.RootFS = rootFS
 	}
 
 	if d.HasChange(mkFeatures) {
@@ -3534,10 +3567,6 @@ func parseImportIDWithNodeName(id string) (string, string, error) {
 	return nodeName, id, nil
 }
 
-func getContainerDiskVolume(rawVolume string, vmID int, diskID int) string {
-	return fmt.Sprintf("%s:vm-%d-disk-%d", rawVolume, vmID, diskID)
-}
-
 func skipDnsDiffIfEmpty(k, oldValue, newValue string, d *schema.ResourceData) bool {
 	dnsDataKey := mkInitialization + ".0." + mkInitializationDNS
 	if k == dnsDataKey+".#" {