[systemd-devel] moving from SysV to systemd - issue with / being ro

[Warpme]

Hi,
I want to switch init system from SysV to systemd-196.
Sys is PXE booted disk-less appliance with rootfs based on overlayfs.

Currently I can PXEboot, successfully switch root from initrd to 
overlayfs based root, systemd starts and executes many of it's units.
Unfortunately user units are failing due / is read-only.
When I issue "mount -o remount,rw /"  - root becomes rw - so it looks 
like systemd for some reason isn't remounting root to rw.
Interesting is that exactly the same initrd->overlayfs script (see 
below) works OK for SysV - so I think issue isn't in my pivot_root 
procedure but rather systemd receives / in rw but leaves in ro (as 
"mount -o remount,rw /" allows to write to /).

Script switching initrd to overlayfs root looks following:

/bin/mount -n -t tmpfs none /rw
/bin/mkdir -p /rw/rootfs
/bin/mount -n -t overlayfs -o lowerdir=/rootfs-ro,upperdir=/rw/rootfs 
none /rootfs
cd /rootfs
/bin/mkdir -p initrd proc sys
/sbin/pivot_root . initrd
exec /usr/sbin/chroot . /usr/lib/systemd/systemd

Where issue might be?