From 91214a37ef4eb8042d2598aa89bae52b410d11a7 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Tue, 13 Dec 2016 12:45:19 +0100 Subject: fstab-generator: add support for volatile boots This adds support for a new kernel command line option "systemd.volatile=" that provides the same functionality that systemd-nspawn's --volatile= switch provides, but for host systems (i.e. systems booting with a kernel). It takes the same parameter and has the same effect. In order to implement systemd.volatile=yes a new service systemd-volatile-root.service is introduced that only runs in the initrd and rearranges the root directory as needed to become a tmpfs instance. Note that systemd.volatile=state is implemented different: it simply generates a var.mount unit file that is part of the normal boot and has no effect on the initrd execution. The way this is implemented ensures that other explicit configuration for /var can always override the effect of these options. Specifically, the var.mount unit is generated in the "late" generator directory, so that it only is in effect if nothing else overrides it. --- units/.gitignore | 1 + units/systemd-volatile-root.service.in | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+) create mode 100644 units/systemd-volatile-root.service.in (limited to 'units') diff --git a/units/.gitignore b/units/.gitignore index 8fdb6e9ab5..4398a59f91 100644 --- a/units/.gitignore +++ b/units/.gitignore @@ -75,5 +75,6 @@ /systemd-update-utmp.service /systemd-user-sessions.service /systemd-vconsole-setup.service +/systemd-volatile-root.service /tmp.mount /user@.service diff --git a/units/systemd-volatile-root.service.in b/units/systemd-volatile-root.service.in new file mode 100644 index 0000000000..cc4e604e4c --- /dev/null +++ b/units/systemd-volatile-root.service.in @@ -0,0 +1,21 @@ +# This file is part of systemd. +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. + +[Unit] +Description=Enforce Volatile Root File Systems +Documentation=man:systemd-volatile-root.service(8) +DefaultDependencies=no +Conflicts=shutdown.target +After=sysroot.mount +Before=initrd-root-fs.target shutdown.target +Conflicts=shutdown.target +AssertPathExists=/etc/initrd-release + +[Service] +Type=oneshot +RemainAfterExit=yes +ExecStart=@rootlibexecdir@/systemd-volatile-root yes /sysroot -- cgit v1.2.3