Install Proxmox VE on eMMC

Recently I bought a mini PC looking forward to setting up a home router. It started quite well except the specs were higher than I anticipated. 8 GB RAM plus 128 GB eMMC - too much waste for “just a router”, so I figured I’d get some virtual machines to improve its utilization. Choosing the virtualization platform isn’t hard - I’m most familiar with Proxmox VE.

The offcial ISO installer is pretty straightforward, until the last step:

Unable to get device for partition 1 on device /dev/mmcblk0

Solution

The Proxmox VE forum is completely unhelpful this time (1, 2) with staff keeping on saying “it’s not supported”, so I had to look around for alternatives. Fortunately this article is right there:

• 解决 Proxmox VE 无法安装到 eMMC 上的问题 - lookas2001

Turns out it’s hard-coded into Proxmox VE’s Perl installer script, so all you have to do is to patch it:

1. Boot the installer ISO to the first menu, select the second option Install Proxmox VE (Debug mode)
2. The first time you’re present with a command-line prompt, type exit and Enter to skip it. This is a very early stage and you can’t do much here.

3. The second time you have a shell, locate /usr/bin/proxinstall and open it. Text editors such as vi and nano are available.

   For Proxmox VE 8 installer, the file you’re going for is /usr/share/perl5/Proxmox/Sys/Block.pm.

4. Search for unable to get device and you should find some code like this:

    } elsif ($dev =~ m|^/dev/[^/]+/hd[a-z]$|) {
        return "${dev}$partnum";
    } elsif ($dev =~ m|^/dev/nvme\d+n\d+$|) {
        return "${dev}p$partnum";
    } else {
        die "unable to get device for partition $partnum on device $dev\n";
    }
   

   The full code can be found on GitHub if you’d like.

5. See how different kinds of storage devices are enumerated? Now add /dev/mmcblk to the list like this:

    } elsif ($dev =~ m|^/dev/[^/]+/hd[a-z]$|) {
        return "${dev}$partnum";
    } elsif ($dev =~ m|^/dev/nvme\d+n\d+$|) {
        return "${dev}p$partnum";
    } elsif ($dev =~ m|^/dev/mmcblk\d+$|) {
        return "${dev}p$partnum";
    } else {
        die "unable to get device for partition $partnum on device $dev\n";
    }
   

6. Save your edits and type exit. Proceed with the installation as normal. Select /dev/mmcblk0 (without the bootX suffix) as the install target. You may want to disable swap to avoid rapid wearing of the eMMC.
7. The next time you have a shell, use exit to skip it. Nothing to do here.

Rambling

While it’s possible to install Proxmox VE on top of a matching version of Debian, it’s tedious to install Debian just for PVE. The last time I had to do it this way was on very old hardware that the PVE installer just crashed (X server died), and that the PVE installer didn’t have a CLI version. Plus a standard Debian installation typically comes with extra stuff that you don’t want on a PVE system (or want to get rid of ASAP).

It’s also possible to modify the installer script beforehand, but you need to unpack pve-installer.squashfs and re-pack it into the ISO. You should think more seriously if you want to install PVE on a lot of eMMC devices.