Snap "lxd" assumes unsupported features: snapd2.39

Not sure whether this is the right place to ask this question, but here goes:
On a new Debian Buster (10.4.0) clean install I installed snapd then tried to install lxd using the command line:

snap install lxd

This returns the error:
error: cannot perform the following tasks:

  • Mount snap “lxd” (15067) (snap “lxd” assumes unsupported features: snapd2.39 (try to update snapd and refresh the core snap))

The version of snapd installed with Buster is:
snap version
snap 2.37.4-1+b1
snapd 2.37.4-1+b1
series 16
debian 10
kernel 4.19.0-9-amd64

I am lost as to how to update snapd to 2.39 as implied, so any advice would be appreciated.

Many thanks,

Roy

Hey :slight_smile:

Try installing the “core” snap first. You can then install lxd normally.

Thanks for the speedy reply. Yes, that fixed it. Perhaps the documentation needs to be updated to include this step?

2 Likes

I had this same problem exactly and I had already installed snap first and then snapd.

What fixed the problem for me was to install the hello-world app and run it to check that snap was working.

After that, installing lxd worked.

Cheers

@zyga

Do you know why this is needed? Should the documentation for installing snap on Debian be updated for this?

On some distros (currently just Debian and Ubuntu), snapd supports a “re-exec” feature:

What this means is that when the .deb packaged snap, snapd, etc tools are executed, they will check if the snapd or core snaps are installed and simply call exec() on the equivalent binary found there.

This means that you can be running a newer version of snapd than is delivered by the distro. Of course, this doesn’t happen until one of those two snaps is installed on the system.

1 Like

As James explained below, snapd in Debian benefits from the re-execution system, where the core snap provides an updated copy of snapd itself.

The installation instructions should be amended to suggest installing core before installing another snap.

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Fixed: Installing snap on Debian

The docs already suggested to first install the hello-world snap, but I wouldn’t follow that so I can’t blame other people for doing the same :wink: