Guide: Volumes and Images

Operations on Volumes

Create and Attach a Volume

1. Log in to the Dashboard and select the correct region (top left).
2. Go to Volumes → Volumes → Create Volume
3. Fill in the form:
   • Name: Assign a descriptive name.
   • Source: No source, empty volume (default).
   • Type: Choose a volume type, if options are available.
   • Size: Set the desired size in GiB (e.g., 20).
   • Click Create Volume.
4. Once created, go to Volumes → Volumes, select the new volume, then:
   • Click Manage Attachments.
   • Choose the target instance and click Attach Volume.
5. Note the device name shown after attachment (e.g., /dev/vdb or /dev/sdb).

Format and Mount the Volume inside the VM

1. SSH into your VM: ssh -i /path/to/private-key <user>@<IP-address>
2. Check available block devices with lsblk The new volume will appear with no mount point.
3. Create a file system, e.g. for ext4: sudo mkfs.ext4 /dev/vdb
   • ⚠️ Deletes all existing data on the volume!
4. Create a mount point: sudo mkdir -p /mnt/volume
5. Mount the volume: sudo mount /dev/vdb /mnt/volume
6. (Optional) Set ownership: sudo chown $USER:$USER /mnt/volume

Mount the Volume Automatically at Boot

1. Find the UUID of the device: lsblk -f
2. Edit /etc/fstab and add a line like this:

   UUID=<the-UUID>  /mnt/volume  ext4  defaults,nofail  0  2

3. Test the fstab entry: sudo systemctl daemon-reload; sudo mount -a

Safely Detach a Volume

1. Close all open files inside the VM and unmount the volume: sudo umount /mnt/volume
2. In the Dashboard:
   • Go to Volumes → Volumes
   • Select Volume → Manage Attachments → Detach Volume.

Resize a Volume

1. In the Dashboard:
   • Go to Volumes → Volumes
   • Select Volume → Extend Volume
   • Choose a (larger) New Size and click Extend Volume
2. Inside the VM: Check the new size with lsblk. If it still shows the old size: Stop the services using it, unmount it, and then detach and re-attach the volume in the Dashboard and mount it again.
3. Inside the VM: Expand the filesystem (e.g. for ext4: sudo resize2fs /dev/vdb). Check the result with df -h.

Create a Snapshot (Backup) from a Volume

Note: If the volume is attached, forcing the snapshot may work, but it’s safer to first detach the volume if possible.

1. In the Dashboard:
   • Go to Volumes → Volumes
   • Select Volume → Create Snapshot
   • Choose a descriptive Snapshot Name and click Create Volume Snapshot
2. You can create a new volume from the snapshot later.

Exporting and Importing (Volume-)Images

Connect to bwCloud-OS using the OpenStack client.

For volumes, first create an image from the volume:

# openstack volume list
# openstack image create \
    --volume <UUID> \
    my_volume_as_image

Download an image:

# openstack image list
# openstack image save \
    --file my_image_file.img \
    <UUID>

Upload a local image file to the image catalog of the selected region and create its metadata entry:

# openstack image create \
    --property os_distro=linux \
    --property ssh_user=<USER> \
    --property hw_video_model=cirrus \
    --file my_image_file.img \
    <NAME>