[systemd-devel] [ANNOUNCE] systemd v229
lennart at poettering.net
Thu Feb 11 17:50:08 CET 2016
I just tagged the v229 release of systemd. Enjoy!
CHANGES WITH 229:
* The systemd-resolved DNS resolver service has gained a substantial
set of new features, most prominently it may now act as a DNSSEC
validating stub resolver. DNSSEC mode is currently turned off by
default, but it is expected that this is turned on by default in one
of the next releases. For now, we invite everybody to test the DNSSEC
logic by setting DNSSEC=allow-downgrade in
/etc/systemd/resolved.conf. The service also gained a full set of
D-Bus interfaces, including calls to configure DNS and DNSSEC
settings per link (for consumption by external network management
software). systemd-resolved (and systemd-networkd along with it) now
know to distinguish between "search" and "routing" domains. The
former are used to qualify single-label names, the latter are purely
used for routing lookups within certain domains to specific
links. resolved will now also synthesize RRs for all entries from
* The systemd-resolve tool (which is a client utility for
systemd-resolved, and previously experimental) has been improved
considerably and is now fully supported and documented. Hence it has
moved from /usr/lib/systemd to /usr/bin.
* /dev/disk/by-path/ symlink support has been (re-)added for virtio
* The coredump collection logic has been reworked: when a coredump is
collected it is now written to disk, compressed and processed
(including stacktrace extraction) from a new instantiated service
systemd-coredump at .service, instead of directly from the
/proc/sys/kernel/core_pattern hook we provide. This is beneficial as
processing large coredumps can take up a substantial amount of
resources and time, and this previously happened entirely outside of
systemd's service supervision. With the new logic the core_pattern
hook only does minimal metadata collection before passing off control
to the new instantiated service, which is configured with a time
limit, a nice level and other settings to minimize negative impact on
the rest of the system. Also note that the new logic will honour the
RLIMIT_CORE setting of the crashed process, which now allows users
and processes to turn off coredumping for their processes by setting
* The RLIMIT_CORE resource limit now defaults to "unlimited" for PID 1
and all forked processes by default. Previously, PID 1 would leave
the setting at "0" for all processes, as set by the kernel. Note that
the resource limit traditionally has no effect on the generated
coredumps on the system if the /proc/sys/kernel/core_pattern hook
logic is used. Since the limit is now honoured (see above) its
default has been changed so that the coredumping logic is enabled by
default for all processes, while allowing specific opt-out.
* When the stacktrace is extracted from processes of system users, this
is now done as "systemd-coredump" user, in order to sandbox this
potentially security sensitive parsing operation. (Note that when
processing coredumps of normal users this is done under the user ID
of process that crashed, as before.) Packagers should take notice
that it is now necessary to create the "systemd-coredump" system user
and group at package installation time.
* The systemd-activate socket activation testing tool gained support
for SOCK_DGRAM and SOCK_SEQPACKET sockets using the new --datagram
and --seqpacket switches. It also has been extended to support both
new-style and inetd-style file descriptor passing. Use the new
--inetd switch to request inetd-style file descriptor passing.
* Most systemd tools now honor a new $SYSTEMD_COLORS environment
variable, which takes a boolean value. If set to false, ANSI color
output is disabled in the tools even when run on a terminal that
* The VXLAN support in networkd now supports two new settings
DestinationPort= and PortRange=.
* A new systemd.machine_id= kernel command line switch has been added,
that may be used to set the machine ID in /etc/machine-id if it is
not initialized yet. This command line option has no effect if the
file is already initialized.
* systemd-nspawn gained a new --as-pid2 switch that invokes any
specified command line as PID 2 rather than PID 1 in the
container. In this mode PID 1 will be a minimal stub init process
that implements the special POSIX and Linux semantics of PID 1
regarding signal and child process management. Note that this stub
init process is implemented in nspawn itself and requires no support
from the container image. This new logic is useful to support running
arbitrary command lines in the container, as normal processes are
generally not prepared to run as PID 1.
* systemd-nspawn gained a new --chdir= switch for setting the current
working directory for the process started in the container.
* "journalctl /dev/sda" will now output all kernel log messages from
the specified device, in addition to all devices that are parents of
it. This should make log output about devices pretty useful, as long
as kernel drivers attach enough metadata to the log messages. (The
usual SATA drivers do.)
* The sd-journal API gained two new calls
sd_journal_has_runtime_files() and sd_journal_has_persistent_files()
that report whether log data from /run or /var has been found.
* journalctl gained a new switch "--fields" that prints all journal
record field names currently in use in the journal. This is backed
by two new sd-journal API calls sd_journal_enumerate_fields() and
* Most configurable timeouts in systemd now expect an argument of
"infinity" to turn them off, instead of "0" as before. The semantics
from now on is that a timeout of "0" means "now", and "infinity"
means "never". To maintain backwards compatibility, "0" continues to
turn off previously existing timeout settings.
* "systemctl reload-or-try-restart" has been renamed to "systemctl
try-reload-or-restart" to clarify what it actually does: the "try"
logic applies to both reloading and restarting, not just restarting.
The old name continues to be accepted for compatibility.
* On boot-up, when PID 1 detects that the system clock is behind the
release date of the systemd version in use, the clock is now set
to the latter. Previously, this was already done in timesyncd, in order
to avoid running with clocks set to the various clock epochs such as
1902, 1938 or 1970. With this change the logic is now done in PID 1
in addition to timesyncd during early boot-up, so that it is enforced
before the first process is spawned by systemd. Note that the logic
in timesyncd remains, as it is more comprehensive and ensures
montonic clocks by maintaining a persistant timestamp file in
/var. Since /var is generally not available in earliest boot or the
initrd, this part of the logic remains in timesyncd, and is not done
by PID 1.
* Support for tweaking details in net_cls.class_id through the
NetClass= configuration directive has been removed, as the kernel
people have decided to deprecate that controller in cgroup v2.
Userspace tools such as nftables are moving over to setting rules
that are specific to the full cgroup path of a task, which obsoletes
these controllers anyway. The NetClass= directive is kept around for
legacy compatibility reasons. For a more in-depth description of the
kernel change, please refer to the respective upstream commit:
* A new service setting RuntimeMaxSec= has been added that may be used
to specify a maximum runtime for a service. If the timeout is hit, the
service is terminated and put into a failure state.
* A new service setting AmbientCapabilities= has been added. It allows
configuration of additional Linux process capabilities that are
passed to the activated processes. This is only available on very
* The process resource limit settings in service units may now be used
to configure hard and soft limits individually.
* The various libsystemd APIs such as sd-bus or sd-event now publicly
expose support for gcc's __attribute__((cleanup())) C
extension. Specifically, for many object destructor functions
alternative versions whose names are suffixed with "p" have been
added, which take a pointer to a pointer to the object to destroy,
instead of just a pointer to the object itself. This is useful because
these destructor functions may be used directly as parameters to the
cleanup construct. Internally, systemd has been a heavy user of the
GCC extension since a long time, and with this change similar support
is now available to consumers of the library outside of systemd. Note
that by using this extension in your sources compatibility with old
and strictly ANSI compatible C compilers is lost. However, any gcc or
LLVM version of recent years have supported this extension.
* Timer units gained support for a new setting RandomizedDelaySec= that
allows configuring some additional randomized delay to the configured
time. This is useful to spread out timer events to avoid load peaks in
clusters or larger setups.
* Calendar time specifications now support sub-second accuracy.
* Socket units now support listening on SCTP and UDP-lite protocol
* The sd-event API now comes with a full set of man pages.
* Older versions of systemd contained experimental support for
compressing journal files and coredumps with the LZ4 compressor that
was not compatible with the lz4 binary (due to API limitations of the
lz4 library). This support has been removed; only support for files
compatible with the lz4 binary remains. This LZ4 logic is now
officially supported and no longer considered experimental.
* The dkr image import logic has been removed again from importd. dkr's
micro-services focus doesn't fit into the machine image focus of
importd, and quickly got out of date with the upstream dkr API.
* Creation of the /run/lock/lockdev/ directory was dropped from
tmpfiles.d/legacy.conf. Better locking mechanisms like flock() have
been available for many years. If you still need this, you need to
create your own tmpfiles.d config file with:
d /run/lock/lockdev 0775 root lock -
Contributions from: Abdo Roig-Maranges, Alban Crequy, Aleksander
Adamowski, Alexander Kuleshov, Andreas Pokorny, Andrei Borzenkov,
Andrew Wilcox, Arthur Clement, Beniamino Galvani, Casey Schaufler,
Chris Atkinson, Chris Mayo, Christian Hesse, Damjan Georgievski, Dan
Dedrick, Daniele Medri, Daniel J Walsh, Daniel Korostil, Daniel Mack,
David Herrmann, Dimitri John Ledkov, Dominik Hannen, Douglas Christman,
Evgeny Vereshchagin, Filipe Brandenburger, Franck Bui, Gabor Kelemen,
Harald Hoyer, Hayden Walles, Helmut Grohne, Henrik Kaare Poulsen,
Hristo Venev, Hui Wang, Indrajit Raychaudhuri, Ismo Puustinen, Jakub
Wilk, Jan Alexander Steffens (heftig), Jan Engelhardt, Jan Synacek,
Joost Bremmer, Jorgen Schaefer, Karel Zak, Klearchos Chaloulos,
lc85446, Lennart Poettering, Lukas Nykryn, Mantas Mikulėnas, Marcel
Holtmann, Martin Pitt, Michael Biebl, Michael Olbrich, Michael Scherer,
Michał Górny, Michal Sekletar, Nicolas Cornu, Nicolas Iooss, Nils
Carlson, nmartensen, nnz1024, Patrick Ohly, Peter Hutterer, Phillip Sz,
Ronny Chevalier, Samu Kallio, Shawn Landden, Stef Walter, Susant
Sahani, Sylvain Plantefève, Tadej Janež, Thomas Hindoe Paaboel
Andersen, Tom Gundersen, Torstein Husebø, Umut Tezduyar Lindskog, Vito
Caputo, WaLyong Cho, Yu Watanabe, Zbigniew Jędrzejewski-Szmek
-- Berlin, 2016-02-11
Lennart Poettering, Red Hat
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