[systemd-devel] [ANNOUNCE] systemd v226
dh.herrmann at gmail.com
Tue Sep 8 06:32:44 PDT 2015
Here's the next version of systemd, v226:
As usual, many bug-fixes and cleanups, but also a rather large set of
new features this time, including support for unified cgroups, many
DHCP improvements, extensions to the polkit integration, nspawn
configuration files, and many more.
Thanks to everyone who contributed to this release!
CHANGES WITH 226:
* The DHCP implementation of systemd-networkd gained a set of
- The DHCP server now supports emitting DNS and NTP
information. It may be enabled and configured via
EmitDNS=, DNS=, EmitNTP=, and NTP=. If transmission of DNS
and NTP information is enabled, but no servers are
configured, the corresponding uplink information (if there
is any) is propagated.
- Server and client now support transmission and reception
of timezone information. It can be configured via the
newly introduced network options UseTimezone=,
EmitTimezone=, and Timezone=. Transmission of timezone
information is enabled between host and containers by
default now: the container will change its local timezone
to what the host has set.
- Lease timeouts can now be configured via
MaxLeaseTimeSec= and DefaultLeaseTimeSec=.
- The DHCP server improved on the stability of
leases. Clients are more likely to get the same lease
information back, even if the server loses state.
- The DHCP server supports two new configuration options to
control the lease address pool metrics, PoolOffset= and
* The encapsulation limit of tunnels in systemd-networkd may
now be configured via 'EncapsulationLimit='. It allows
modifying the maximum additional levels of encapsulation
that are permitted to be prepended to a packet.
* systemd now supports the concept of user buses replacing
session buses, if used with dbus-1.10 (and enabled via dbus
--enable-user-session). It previously only supported this on
kdbus-enabled systems, and this release expands this to
* systemd-networkd now supports predictable interface names
for virtio devices.
* systemd now optionally supports the new Linux kernel
"unified" control group hierarchy. If enabled via the kernel
command-line option 'systemd.unified_cgroup_hierarchy=1',
systemd will try to mount the unified cgroup hierarchy
directly on /sys/fs/cgroup. If not enabled, or not
available, systemd will fall back to the legacy cgroup
hierarchy setup, as before. Host system and containers can
mix and match legacy and unified hierarchies as they
wish. nspawn understands the $UNIFIED_CROUP_HIERARCHY
environment variable to individually select the hierarchy to
use for executed containers. By default, nspawn will use the
unified hierarchy for the containers if the host uses the
unified hierarchy, and the legacy hierarchy otherwise.
Please note that at this point the unified hierarchy is an
experimental kernel feature and is likely to change in one
of the next kernel releases. Therefore, it should not be
enabled by default in downstream distributions yet. The
minimum required kernel version for the unified hierarchy to
work is 4.2. Note that when the unified hierarchy is used
for the first time delegated access to controllers is
safe. Because of this systemd-nspawn containers will get
access to controllers now, as will systemd user
sessions. This means containers and user sessions may now
manage their own resources, partitioning up what the system
* A new special scope unit "init.scope" has been introduced
that encapsulates PID 1 of the system. It may be used to
determine resource usage and enforce resource limits on PID
1 itself. PID 1 hence moved out of the root of the control
* The cgtop tool gained support for filtering out kernel
threads when counting tasks in a control group. Also, the
count of processes is now recursively summed up by
default. Two options -k and --recursive= have been added to
revert to old behaviour. The tool has also been updated to
work correctly in containers now.
* systemd-nspawn's --bind= and --bind-ro= options have been
extended to allow creation of non-recursive bind mounts.
* libsystemd gained two new calls sd_pid_get_cgroup() and
sd_peer_get_cgroup() which return the control group path of
a process or peer of a connected AF_UNIX socket. This
function call is particularly useful when implementing
delegated subtrees support in the control group hierarchy.
* The "sd-event" event loop API of libsystemd now supports
correct dequeuing of real-time signals, without losing
* When systemd requests a PolicyKit decision when managing
units it will now add additional fields to the request,
including unit name and desired operation. This enables more
powerful PolicyKit policies, that make decisions depending
on these parameters.
* nspawn learnt support for .nspawn settings files, that may
accompany the image files or directories of containers, and
may contain additional settings for the container. This is
an alternative to configuring container parameters via the
nspawn command line.
Contributions from: Cristian Rodríguez, Daniel Mack, David
Herrmann, Eugene Yakubovich, Evgeny Vereshchagin, Filipe
Brandenburger, Hans de Goede, Jan Alexander Steffens, Jan
Synacek, Kay Sievers, Lennart Poettering, Mangix, Marcel
Holtmann, Martin Pitt, Michael Biebl, Michael Chapman, Michal
Sekletar, Peter Hutterer, Piotr Drąg, reverendhomer, Robin
Hack, Susant Sahani, Sylvain Pasche, Thomas Hindoe Paaboel
Andersen, Tom Gundersen, Torstein Husebø
-- Berlin, 2015-09-08
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