Installing Nextcloud on Proxmox (part 1)

Today we are going to install Nextcloud on Proxmox on a Linux Ubuntu VM.

1. Preparing Ubuntu ISO image on Proxmox

Because we are starting from a fresh Proxmox server we first have to download the ISO image that serves as the base OS.

Login to Proxmox web interface
Click local > ISO Images > Download from URL
Then paste the URL > Query URL > Download

https://releases.ubuntu.com/26.04/ubuntu-26.04-live-server-amd64.iso

2. Creating the VM

From within the Proxmox web interface:

Click button: Create VM
Name: nextcloud01
Start at boot: YES
ISO Image: Choose the Ubuntu 26.04 image from step 1
System: Qemu agent: YES
Disk 1: 50 GB for OS (I chose 100G B)
Disk 2: 500+ GB for data (I chose 2048 GB)
CPU: 4 cores
Memory: 8192 MB (8 GB)

Creating the VM can take a while, I am going to get myself a coffee :)

3. Ubuntu 26.04 installation

After creating the VM we have to go through the Ubuntu installation wizard.

(I needed to lower my memory setting because my proxmox host did not have enough memory available to start the VM)

Stick to the defaults unless mentioned:

Start the VM
Select language, keyboard layout, etc.
I configured a static IP but you can also just use DHCP and make it static in your router
Choose your OS disk, not your data disk!
Install OpenSSH server
Do not install any snap packages!

4. QEMU Guest Agent

After installation login for the first time and install the QEMU Guest Agent so Proxmox can talk to the VM.

Why?

Show IP in Proxmox Summary tab
Clean shutdowns
Consistent backups (the agent freezes the filesystem during a Proxmox snapshot/backup, ensuring data integrity)

sudo apt install qemu-guest-agent -y

Is the IP address shown in the Summary tab in the Proxmox web interface?

Yes? Great, continue.
No? Reboot and check if “Qemu Guest agent” is enabled for the VM in Proxmox under the VM options.

Now let’s test SSH access to confirm the VM is fully operational.

Open the Terminal on your desktop:

ssh user@ip-address

And install updates:

sudo apt update && sudo apt upgrade -y

6. Mount the data disk

When we created the VM we added a second data disk. Before we can use it, we need to partition, format and mount it.

# Identify the data disk (look for unformatted disk, e.g. sdb)
lsblk

# Format the disk as ext4
sudo mkfs.ext4 /dev/sdb

# Create the mount point
sudo mkdir /mnt/datadisk

# Get the disk UUID
sudo blkid /dev/sdb

# Add to fstab (replace with your actual UUID)
sudo nano /etc/fstab

Add this line at the bottom of fstab:

UUID=your-uuid-here /mnt/datadisk ext4 defaults 0 2

# Mount and verify
sudo mount -a
df -h