Creating and using volumes¶

Creating a volume via the dashboard¶

The easiest method to create and attach a volume to an instance would be to use the Catalyst Cloud web dashboard. From the volumes tab on the dashboard you can create, delete, and manage your block storage volumes.

Once you are here we we navigate to the Create Volume button on the top right. We are then met with this screen.

From this example I have already filled out the requirements to create the instance:

A name
The volume type
The size (in this example 50 GB)
The region

Once we have all of these set, then we are create our volume.

Warning

The create volume screen allows you to select a volume source to create your new volume from. We strongly advise against using “snapshot” or “volume” as a source for the new volume. These will create hard dependencies on the volume or snapshot selected, meaning you cannot delete the source volume or snapshot until your new volume and all others created from the same source are deleted.

After we have our new volume, we then are going to attach our volume to an instance. To do this we have to go to the Manage Attachments section.

From this screen we select the instance we want to attach our volume to. The dropdown from this pop up will display all your instances; for this example I am using an instance called “basic-instance”. We also provide the path in the file structure where we want our volume to be available from; in this example I use /dev/vdb.

Once this is done, then you should be able to see your new volume attached to your instance.

Creating a volume using programmatic methods¶

To create and attach a new volume, you can use one of the methods below:

Note

You must have sourced an openrc file before you can use any of the following methods to create or attach a volume.

The following command will create a volume on your project:

$ openstack volume create --description 'database volume' --size 50 db-vol-01

+---------------------+--------------------------------------+
| Field               | Value                                |
+---------------------+--------------------------------------+
| attachments         | []                                   |
| availability_zone   | nz-por-1a                            |
| bootable            | false                                |
| consistencygroup_id | None                                 |
| created_at          | 2016-08-18T23:08:40.021641           |
| description         | database volume                      |
| encrypted           | False                                |
| id                  | 7e94a2f6-b4d2-47f1-83f7-xxxxxxxxxxxx |
| multiattach         | False                                |
| name                | db-vol-01                            |
| properties          |                                      |
| replication_status  | disabled                             |
| size                | 50                                   |
| snapshot_id         | None                                 |
| source_volid        | None                                 |
| status              | creating                             |
| type                | b1.standard                          |
| updated_at          | None                                 |
| user_id             | 53b94a52e9dcxxxxxxx0079a9a3d6434     |
+---------------------+--------------------------------------+

The next command will attach the previous volume to your instance. This command assumes that your volume name is unique; If you have volumes with duplicate names you will need to use the volume ID to attach the correct volume to your compute instance.

attach-volume.sh¶

$ openstack server add volume <INSTANCE_NAME> <VOLUME_NAME>

The following assumes that you have already sourced an openRC file and that you have downloaded and installed terraform. Terraform works by reading a template file and creating resources on the cloud based off of the defined structure in the template.

The template file we are using will create a volume and attach it to an existing instance.

Save the following script and change the variables so that they fit your project:

terraform-block-storage.tf¶

# Configure the OpenStack Provider
# This example relies on OpenStack environment variables
# If you wish to set these credentials manualy please consult
# https://www.terraform.io/docs/providers/openstack/index.html
provider "openstack" {
}

variable "public_network_id" {
  default = "<INSERT YOUR REGION NETWORK ID FROM THE BELOW LIST>"
}

# From: http://docs.catalystcloud.io/network.html?highlight=public%20network
#nz-por-1	849ab1e9-7ac5-4618-8801-xxxxxxxxxxxx
#nz-hlz-1	f10ad6de-a26d-4c29-8c64-xxxxxxxxxxxx

variable "volume_image_ID" {
  default = "<INSERT THE IMAGE ID FROM YOUR REGION>"
}

variable "instance_id" {
  default = "<INSERT INSTANCE ID>"
}

variable "volume_type" {
  default = "b1.standard"
}

#-----------------------------------------------------------------------------------------------

#Create an NVME storage volume
resource "openstack_blockstorage_volume_v2" "testvol" {
  size          = 50
  image_id      = "${var.volume_image_ID}"
  volume_type   = "${var.volume_type}"
}

#Explicitely attach the storage volume to the instance
resource "openstack_compute_volume_attach_v2" "va_1" {
  instance_id = "${var.instance_id}"
  volume_id   = "${openstack_blockstorage_volume_v2.testvol.id}"
}

The commands you will need to use are:

terraform-create.sh¶

$ terraform init

----------------------------------------------

$ terraform plan

----------------------------------------------

$ terraform apply

To remove all resources associated with this terraform plan, you can use the following:

terraform-destroy.sh¶

terraform destroy

Heat is the native Openstack orchestration tool and functions by reading a template and creating a stack on your project using information contained within the template and from your environment variables.

The following template will create a new volume and attach it to an existing instance on your project:

heat-create-volume.yaml¶

#
# HOT template for creating a new volume and attaching it to an instance
#
heat_template_version: 2015-04-30

description: >
  HOT template for building a new volume and attaching it to an instance

parameter_groups:
- label: New-Volume
  description: New volume creation and attachment
  parameters:
  - volume
  - volume_size
  - instance

parameters:

  volume:
    type: string
    description: Name of the new volume
    default: heat-new-volume

  volume_size:
    type: number
    description: size of the volume you want to create
    default: 5
    constraints:
      - range: {min: 1, max: 100}
        description: the size of the volume is between 1 - 100GB

  instance:
    type: string
    description: ID of the instance you want the volume to be attached to
    default: <INSERT-ID-HERE>


resources:
  cinder_volume:
    type: OS::Cinder::Volume
    properties:
      size: { get_param: volume_size }

  volume_attachment:
    type: OS::Cinder::VolumeAttachment
    properties:
      volume_id: { get_resource: cinder_volume }
      instance_uuid: { get_param: instance }
      mountpoint: /dev/sdb

You will need to save this file as a .yaml and change some of the parameters so that your volume will attach to the correct instance.

Once that is done, you will need to validate the template before it is used to create your stack.

# Navigate to the directory that contains your yaml file and run the following:

$ openstack orchestration template validate -t heat-create-volume.yaml

If the template is outputted on your command line, then the template is valid. If you receive an error, then you will need to fix the error before you can use the template.

Once you have a valid template, you can run the following code to create a new stack named new-volume-stack:

$ openstack stack create -t heat-create-volume.yaml new-volume-stack

The stack_status indicates that creation is in progress. Use the event list command to check on the stack’s orchestration progress:

$  openstack stack event list new-volume-stack

Warning

If a stack has been orchestrated using Heat, it is generally a good idea to also use Heat to delete that stack’s resources. Deleting components of a Heat orchestrated stack manually, whether using the other command line tools or the web interface, can result in resources or stacks being left in an inconsistent state.

To delete the new-volume-stack you can use the following code:

$ openstack stack delete new-volume-stack
Are you sure you want to delete this stack(s) [y/N]? y

Using volumes on Linux¶

The example below illustrates the use of a volume without LVM.

Warning

Please note that this configuration is not suitable for production servers, but rather a demonstration that block volumes behave like regular disk drives attached to a server.

Once we have a command line that is connected via ssh to our instance, we check that our disk is recognized by the OS using fdisk:

$ sudo fdisk -l /dev/vdb
Disk /dev/vdb: 50 GiB, 53687091200 bytes, 104857600 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Now use fdisk to create a partition on the disk:

$ sudo fdisk /dev/vdb

Welcome to fdisk (util-linux 2.27.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x1552cd32.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-104857599, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-104857599, default 104857599):

Created a new partition 1 of type 'Linux' and of size 50 GiB.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

Check the partition using lsblk:

$ lsblk
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda    253:0    0  10G  0 disk
└─vda1 253:1    0  10G  0 part /
vdb    253:16   0  50G  0 disk
└─vdb1 253:17   0  50G  0 part

Make a new filesystem on the partition:

$ sudo mkfs.ext4 /dev/vdb1
mke2fs 1.42.13 (17-May-2015)
Creating filesystem with 5242624 4k blocks and 1310720 inodes
Filesystem UUID: 7dec7fb6-ff38-453b-9335-xxxxxxxxxxxx
Superblock backups stored on blocks:
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
    4096000

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

Create a directory where you wish to mount this file system:

$ sudo mkdir /mnt/extra-disk

Mount the file system:

$ sudo mount /dev/vdb1 /mnt/extra-disk

Label the partition:

$ sudo tune2fs -L 'extra-disk' /dev/vdb1
tune2fs 1.42.13 (17-May-2015)
$ sudo blkid
/dev/vda1: LABEL="cloudimg-rootfs" UUID="98c51306-83a2-49da-94a9-xxxxxxxxxxxx" TYPE="ext4" PARTUUID="8cefe526-01"
/dev/vdb1: LABEL="extra-disk" UUID="7dec7fb6-ff38-453b-9335-xxxxxxxxxxxx" TYPE="ext4" PARTUUID="235ac0e4-01"

If you want the new file system to be mounted when the system reboots then you should add an entry to /etc/fstab. For example, making sure you have sudo privilege:

$ cat /etc/fstab
LABEL=cloudimg-rootfs /               ext4    defaults    0 1
LABEL=extra-disk      /mnt/extra-disk ext4    defaults    0 2

Note

When referring to block devices in /etc/fstab it is recommended that UUID or volume label is used instead of using the device name explicitly. It is possible for device names to change after a reboot, particularly when there are multiple attached volumes.