Downloading ISO Directly to Proxmox Using Command Line

This is usually the faster way to get any iso to proxmox, especially if you are connecting to proxmox via some not so fast internet connection. But if you still prefer to use the web GUI, please refer to this post on how to do it via the web UI.

Go to the directory where iso's are being kept in proxmox
# cd /var/lib/vz/template/iso

If you have not downloaded the ISO, you can download it directly in this directory. For example I want to download a Centos 8 ISO
# wget http://centos.ipserverone.com/centos/8-stream/isos/x86_64/CentOS-Stream-8-x86_64-20191219-dvd1.iso

Once done, refresh the webUI

Uploading iso to Proxmox

To upload iso to proxmox, so that the iso can be used to create VM, please follow below steps

1. Login to proxmox

2. On the left hand side, expand Datacenter, until you see node/s

3. Expand the node until you see local. Click on "local"

4. On the right hand side, click "Content"

5. Click "Upload"

6. Select the iso file that you want to upload, and click "Upload"

7. Once uploaded, you will see the iso listed on the right hand side. Please refer below picture for clearer view

How to test that your usb live cd is working

To do this, you need qemu-kvm. Install it:
$ sudo apt install qemu-kvm


Check the address of your usb, by using dmesg
$ dmesg | grep sd


Once you have the address, you can start it using below command (make sure you allocate at least 1024M memory, else it will return kernel panic)
$ sudo qemu-system-x86_64 -m 1024 -hda /dev/sdb


To use a cdrom, you can use below command
$ sudo qemu-system-x86_64 -m 1024 -cdrom /dev/cdrom


You can also test an iso file, using below command
$ sudo qemu-system-x86_64 -m 1024 -cdrom centos.iso