On Tue, Mar 31, 2020 at 1:10 AM Lennart Poettering <mzxreary@xxxxxxxxxxx> wrote:
On Fr, 27.03.20 10:17, Preston L. Bannister (preston@xxxxxxxxxxxx) wrote:
> Had the (possibly) clever notion of using an overlayfs as the root mount,
> with a tmpfs as the upper, and the usual persistent volume as the
> lower.
Current systemd versions support this natively, just boot with
"systemd.volatile=overlay" on the kernel cmdline. Doubt this is in
centos8 yet, though.
I can confirm that adding "systemd.volatile=yes" on the kernel cmdline with Centos 8 results in failed boot. Some obscure error related to initramfs that I have not tried to typify. Also Centos 8 has systemd 232, and it looks like "systemd.volatile=overlay" handed later in systemd.
Note that overlayfs is a weird fs, it has strange, non-posixy
semantics (inode nrs a fucked). It generally doesn't work as well as
people want it to work, and while you might get away with using it for
small, well-defined scenarios it's not suitable for complex, general
purpose systems to run as root fs.
"systemd.volatile=overlay" is a nice tool for testing and development,
and maybe some very specific setups, but it's not really something i'd
want to deploy in production in big scale.
OK - had not hear that before. Thanks. Did see some odd behavior, but assumed (and still) the fault was mine.
Look what src/volatile-root/volatile-root.c in current systemd
versions is doing. It's relatively straight-forward. You can do
something similar with a shell script.
Looking.
_______________________________________________ systemd-devel mailing list systemd-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/systemd-devel
