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

[Warpme]

On 10/16/13 7:02 PM, Zbigniew Jędrzejewski-Szmek wrote:
> On Wed, Oct 16, 2013 at 06:18:12PM +0200, Warpme wrote:
>> 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?
> What's in /etc/fstab?
>
> Zbyszek
>
Zbyszku,

Here is my fstab:

none / auto remount,rw 0 0

pzdr