In our last guide, we discussed on how to create Cinder Volumes in OpenStack and attach them to running instance. This tutorial will cover how you can extend /grow the size of a Cinder volume.

Resize / Extend Cinder Volume in OpenStack from CLI
If you have configured OpenStack CLI, you can use it to to resize a Cinder volume. To make our guide complete, we’ll create a new volume.
$ openstack volume create --size 10 test-volume
+---------------------+--------------------------------------+
| Field | Value |
+---------------------+--------------------------------------+
| attachments | [] |
| availability_zone | nova |
| bootable | false |
| consistencygroup_id | None |
| created_at | 2019-11-03T20:29:56.000000 |
| description | None |
| encrypted | False |
| id | afec0c14-c5bb-42da-8f87-5a940ff18885 |
| migration_status | None |
| multiattach | False |
| name | test-volume |
| properties | |
| replication_status | None |
| size | 10 |
| snapshot_id | None |
| source_volid | None |
| status | creating |
| type | None |
| updated_at | None |
| user_id | 336acbb7421f47f8be4891eabf0c9cc8 |
+---------------------+--------------------------------------+
Let’s attach it to an instance:
openstack server add volume fedoravm test-volume
Where:
- fedoravm is the name of the instance we’re attaching created volume
- test-volume is the name of the volume
Confirm volume is attached to our VM.
[fedora@fedoravm ~]$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 252:0 0 20G 0 disk
└─vda1 252:1 0 20G 0 part /
vdb 252:32 0 10G 0 disk
Then resize it and confirm the change inside a VM.
# Syntax
$ openstack volume set --size <size> <volume>
Where:
- <size> is the volume size to extend in GB
- <volume> is the volume to modify (name or ID)
But first unmount any partitions inside the instance if configured, then detach the volume.
# Inside VM unmount if mounted
# Then detach
$ openstack server remove volume fedoravm test-volume
I’ll extend the disk to 30 GB
openstack volume set --size 30 test-volume
Re-attach it to the VM.
$ openstack server add volume fedoravm test-volume
Confirm new size:
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 252:0 0 20G 0 disk
└─vda1 252:1 0 20G 0 part /
vdb 252:32 0 30G 0 disk
If the volume was mounted refer to guides below on how to resize:
- How To resize an ext2/3/4 and XFS root partition without LVM
- How to extend root filesystem using LVM on Linux
More on OpenStack:
- How To rename an Instance/Server in OpenStack
- How To Resize OpenStack Instance / Virtual Machine
- How To Set or update VM hostname in AWS / OpenStack / DigitalOcean
- How To Create CentOS 8 KVM Image Template on OpenStack
- How To Create OpenStack Instance With a Fixed / Static IP Address