[WSL] bwrap: kernel does not support user namespaces

[antoineL]

I tried to install Mosaic on WSL2/Ubuntu20.04. Install went relatively smoothly: the only error I saw was while flatpak installed org.freedesktop.Platform.openh264 (I think), when I got

Warning: While trying to apply extra data: apply_extra script failed, exit status 256

Trying to run mosaic, I got

antoineL@MyPC:~$ flatpak run org.d3cod3.Mosaic
bwrap: Creating new namespace failed, likely because the kernel does not support user namespaces.  bwrap must be installed setuid on such systems.
error: ldconfig failed, exit status 256

It seems this particular issue is (somewhat) known elsewhere: cf. opam#3747 which points to OCaml (and bwrap is bubblewrap; with issue #272 open since 2018).
These reports are dated mainly from 2018-19, and WSL is a relatively fast-moving target.
StackOverflow also has a question about it; there is even a 2020 answer which looks like promising: it leads to Jane Street Install OCaml repo; however I cannot saw anything interesting there, looks like a dead end to me.

I am a complete newbie to Mosaic and fastpak, so I cannot attempt to locate where OCaml and/or odap are involved (perhaps this issue belongs to Mosaic-installer? Or even flatpak?), much less propose a path for a solution. But perhaps others might take a look and give useful hints, or perhaps workarounds?

[d3cod3]

Hi antoineL,

i'm sorry but this issue is completely out of the bounds of Mosaic basecode, but thanks a lot for all the detailed info anyway, i will let you know if some solution appears!