On Mon, Jul 9, 2012 at 10:10 AM, Damjan <gdam...@gmail.com> wrote: > Has anyone done any research on stateless ArchLinux instances. > > A stateless Arch would be one where the root filesystem is mounted read-only > and nothing changes there. Thus it can mounted over network (using NFS, NBD > and similar) by several, diskless, PCs at the same time. > > I plan to have per user HOME directories on a server (again NFS or similar), > and users credentials in LDAP. > > /var/run beeing a link to a tmpfs /run, and by using systemd-journal without > /var/log/journal (it will store logs in memory) a lot of things avoid > hitting the disk already. > > I'd use connman for handling the net connection and it seems to require a > writable /var/lib/connman/ > > > Anyone with any experience with this?
I have been working towards initscripts allowing this, and various upstreams (such as util-linux) should also support this setup. That said, I have not actually tested this to any great extent, so don't know how well it will work (feedback very welcome!). What should work (but might not!): /etc and /usr (and /lib, /sbin, /bin) should be able to be mounted read-only. I expect you'll have to figure out how to deal with /etc/resolv.conf, I wonder if NetworkManager has learnt how to deal with this gracefully since I last checked... What will not work: as Rodrigo said, you'll still need /var to be mounted read-write, the point of /var is for applications to be able to write to it. Moreover, /var must be unique to each installation, and cannot be shared (you can put it on an NFS share though, just make sure you have one for each machine). Moreover, even if /etc/ is mounted read-only, you probably want one per machine. You might get away with sharing it, but then all your hostnames will be the same for instance. Importantly: you don't want /etc/machine-id to be shared by different machines (as it needs to be unique). If you do decide to share /etc, you can replace /etc/machine-id by an empty file and systemd will create a random one at every boot (in /run) and use that instead, so you should be fine in this respect. HTH, Tom
