To install Home Assistant on Proxmox from a qcow2 image, download the image to the Proxmox host, create a new virtual machine with no media, and import the downloaded disk into the VM. In the Proxmox UI, configure the VM’s hardware to boot from the imported disk, start the VM, and then access the web interface to complete the setup.

1. Download the qcow2 image
Go to the Home Assistant alternative installation page and copy the URL for the “KVM/Proxmox” .qcow2.xz file.  https://www.home-assistant.io/installation/alternative
In Proxmox, open the shell for your node.
Use wget to download the file. For example: wget <URL_COPIED_FROM_HA_WEBSITE>.
Extract the .qcow2 file from the .xz archive using the unxz command. For example: unxz home-assistant_ova-*.qcow2.xz.

2. Create a new virtual machine
In the Proxmox web UI, click “Create VM” and give it a name.
Under the “OS” tab, select “Do not use any media“.
Under the “System” tab, enable “EFI“, and select an EFI storage location. Change the “machine” to q35 and uncheck “Pre-Enroll Keys“.
Under the “Disks” tab, delete the default disk (e.g., scsi0) that is automatically created.
Set the “CPU” to at least 2 cores and “Memory” to at least 2048 MB.
Click “Finish” to create the VM.

3. Import the disk and set boot order
Go back to the Proxmox shell.
Import the qcow2 disk image using the qm importdisk command, replacing <VMID> with your VM’s ID and <path/to/disk.qcow2> with the actual path to the file. For example: qm importdisk <VMID> /path/to/home-assistant_ova-*.qcow2 local-lvm –format qcow2.
In the Proxmox web UI, select your new VM, go to “Hardware,” and find the “Unused Disk“.
Click on the unused disk and then click “Edit.” In the dialog, select a storage location (e.g., local-lvm) and click “Add”.
Go to the VM’s “Options” menu. Double-click “Boot Order” and move the new disk to the top of the list. You can uncheck the CD-ROM and Network devices to speed up boot time.

4. Boot and onboard Home Assistant
Start the VM from the Proxmox interface.
Open the VM’s “Console” to watch it boot up.
After it has finished booting, it will display an IP address. Go to a web browser on another device and enter that IP address followed by :8123 (e.g., http://192.168.1.50:8123).
You will be taken to the Home Assistant onboarding page to create your user account and set up your smart home.