Symptom Bitbake build fails in a LXC container located on ZFS storage (Proxmox PVE) with a error message “__populate_fs: Could not allocate block in ext2 filesystem while writing file…” Workaround Make a ZFS subvolume with a ext4 filesystem and then mount it into the unprivileged container. The container user has UID 1000 which is mappend to 101000 on the host. zfs create -s -V 80G rpool/tmp-build mkfs.ext4 /dev/zvol/rpool/tmp-build mkdir /tmp-build mount /dev/zvol/rpool/tmp-build /tmp-build # add LXC user's uid to 100000 chown -R 101000:101000 /tmp-build/ # bind mount to LXC container using Proxmox tool pct set 104 -mp0 mp=/tmp-build,/tmp-build Change your config to use the new tmpdir in local.

Create a new LXC Container In Proxmox VE create a unprivileged LXC container with fuse=1,keyctl=1,mknod=1,nesting=1 (I’m not sure if all are needed). In this case I use a Ubuntu 18.04 container. Installation of fuse-overlayfs fuse-overlayfs is a similar to overlayfs runs in userspace and can be used without root permissions1. Unlike overlayfs, fuse-overlayfs can be also used when the backing filesystem is ZFS, like on Proxmox VE. Then inside the container, install a static version of fuse-overlayfs.