Note: I’m based in Korea, so some context here is Korea-specific.

1. Add and Mount a New Disk

  • This part is the same as a regular SSD / HDD mount! If something doesn’t work, feel free to search for Ubuntu hard disk mount and follow along.

  1. Connect the SSD or HDD to the Raspberry Pi.

  2. Run sudo fdisk -l to find the name of the mounted hard disk. In my case, it’s /dev/sda.

Mounted hard disk contents

  1. Carefully format the disk by running sudo wipefs -a /dev/<disk you just identified>. (Example: sudo wipefs -a /dev/sda)
  2. Run sudo mkfs.ext4 /dev/<disk you just identified> to format the disk as ext4.
  3. Run sudo blkid -s UUID -o value /dev/<disk you just identified> to get the unique ID of the disk (in the form 680dfccb-9d8f-431c-ab3b-8c1e6c86e04f).
  4. Create a folder to mount with sudo mkdir /storage-ssd (the location is up to you; for convenience, I mounted it to a folder called /storage-ssd at the root).
  5. Open /etc/fstab with sudo privileges and add UUID=7cf3fc21-74d6-4c01-a835-f8bd36bc3f7b /storage-ssd ext4 defaults 0 0 to the very last line. (Mount to the folder created in step 6.)
  6. Run sudo mount -a to mount the disk you just registered.

2. Register the New Disk with Longhorn

Now let’s register the new disk with Longhorn!

  1. Open the load balancer IP you set up earlier (http://192.168.0.201/) in your browser.
  2. Select Node -> the relevant Node -> Edit Node and disks.

Longhorn settings screenshot, Edit Node and disks

  1. In the disk tag field, enter the same tag as the diskSelector you set when configuring the StorageClass to indicate that this disk belongs to that StorageClass. Then set the Path to the mount folder configured above. Longhorn settings screenshot

  2. Click save and verify that the volume is recognized correctly.

3. Wrapping Up

Great work! You can now reliably supply a distributed storage system to subsequent applications using Longhorn!

Next, I’ll cover how to manage sensitive information like passwords through Git using Sealed Secrets, and after that I plan to set up a Private Docker Registry.

Thank you!