Attaching and Accessing Volumes to an instance

Owned by Chung, Donald (STFC,RAL,SC)
Last updated: Aug 16, 2023 by Chris Green
4 min read

You can only attach a volume to one instance at a time.

Attaching Volume

Web Interface

  1. Click the drop-down menu on the right-hand side (in Actions column) and select MANAGE ATTACHMENTS

  2. Select the right instance and press ATTACH VOLUME

  3. Note the path in the Attached To column of the volume


Command-Line

Get the Server ID (Instances) and Volume ID (Volume) using command

$ openstack server list +--------------------------------------+--------------------------+--------+----------------------------------------+---------------------------------------------------------+--------------+ | ID | Name | Status | Networks | Image | Flavor | +--------------------------------------+--------------------------+--------+----------------------------------------+---------------------------------------------------------+--------------+ | 6b2bedc4-9d8e-4bf3-be63-1dd49bc2e188 | test-resize-rebuild | ACTIVE | Internal=172.16.102.207 | ubuntu-focal-20.04-gui | c3.small | +--------------------------------------+--------------------------+--------+----------------------------------------+---------------------------------------------------------+--------------+ $ openstack volume list +--------------------------------------+-------------------+-----------+------+-----------------------------------+ | ID | Name | Status | Size | Attached to | +--------------------------------------+-------------------+-----------+------+-----------------------------------+ | 2d61791d-5f52-46e1-81ac-05221c308fe8 | test-cli-snapshot | available | 3 | | +--------------------------------------+-------------------+-----------+------+-----------------------------------+

Run

openstack server add volume <server-id> <volume-id> --device <device-name>



$ openstack server add volume 6b2bedc4-9d8e-4bf3-be63-1dd49bc2e188 2d61791d-5f52-46e1-81ac-05221c308fe8 --device /dev/vdb +-----------+--------------------------------------+ | Field | Value | +-----------+--------------------------------------+ | ID | 2d61791d-5f52-46e1-81ac-05221c308fe8 | | Server ID | 6b2bedc4-9d8e-4bf3-be63-1dd49bc2e188 | | Volume ID | 2d61791d-5f52-46e1-81ac-05221c308fe8 | | Device | /dev/vdb | +-----------+--------------------------------------+

Accessing the volume

  1. Log-in to the attached instance using SSH

  2. (Optional only for new volume) Format the volume (we use ext4 here and assume the attach point is /dev/vdb) (Formatting will wipe your data): 

    sudo mkfs.ext4 /dev/vdb



  3. Use lsblk to confirm the device path (usually type disk). The value shown in OpenStack can be inaccurate.

    $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT loop0 7:0 0 73.1M 1 loop /snap/lxd/21902 loop1 7:1 0 55.4M 1 loop /snap/core18/2128 loop3 7:3 0 72.6M 1 loop /snap/lxd/21750 loop4 7:4 0 61.9M 1 loop /snap/core20/1169 loop5 7:5 0 32.5M 1 loop /snap/snapd/13640 loop7 7:7 0 42.2M 1 loop /snap/snapd/14066 loop8 7:8 0 55.5M 1 loop /snap/core18/2253 loop9 7:9 0 61.9M 1 loop /snap/core20/1242 sr0 11:0 1 470K 0 rom /mnt/context vda 252:0 0 20G 0 disk ├─vda1 252:1 0 19.9G 0 part / ├─vda14 252:14 0 4M 0 part └─vda15 252:15 0 106M 0 part /boot/efi vdc 252:32 0 3G 0 disk



  4. Mount the volume (we use the folder /mnt/test-volume as example)

    sudo mkdir /mnt/test-volume



  5. Add this mount point to /etc/fstab, so it will be mounted automatically on startup 

    sudo vim /etc/fstab 



  6. Add/edit the following line: 

    /dev/vdb /mnt/test-volume ext4 defaults 0 0



  7. You still need to manually mount it now 

    sudo mount /mnt/test-volume



  8. (Optional)You may also want to change the permission of the directory using chmod to enable read/write without sudo



    chmod