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NEWS: more entries and some rewordings

This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2019-07-30 16:21:21 +02:00
parent 7c6de13f1b
commit 4860f5c2ae
1 changed files with 93 additions and 63 deletions
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156
NEWS
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@ -28,22 +28,22 @@ CHANGES WITH 243 in spe:
killed. With this change behaviour is thus adjusted to match the
documentation.
* The "kernel.pid_max" sysctl is now bumped to 4194304 by default,
i.e. the full 22bit range the kernel allows, up from the old 16bit
range. This should improve security and robustness a bit, as PID
collisions are made less likely (though certainly still
possible). There are rumours this might create compatibility
* On 64 bit systems, the "kernel.pid_max" sysctl is now bumped to
4194304 by default, i.e. the full 22bit range the kernel allows, up
from the old 16bit range. This should improve security and
robustness, as PID collisions are made less likely (though certainly
still possible). There are rumours this might create compatibility
problems, though at this moment no practical ones are known to
us. Downstream distributions are hence advised to undo this change in
their builds if they are concerned about maximum compatibility, but
for everybody else we recommend leaving the value bumped. Besides
improving security and robustness this should also simplify things as
the maximum number of allowed concurrent tasks was previously bounded
by both "kernel.pid_max" and "kernel.threads-max" and now only a
single knob is left ("kernel.threads-max"). There have been concerns
that usability is affected by this change because larger PID numbers
are harder to type, but we believe the change from 5 digit PIDs to 7
digit PIDs is not too hampering for usability.
by both "kernel.pid_max" and "kernel.threads-max" and now effectively
only a single knob is left ("kernel.threads-max"). There have been
concerns that usability is affected by this change because larger PID
numbers are harder to type, but we believe the change from 5 digits
to 7 digits doesn't hamper usability.
* MemoryLow= and MemoryMin= gained hierarchy-aware counterparts,
DefaultMemoryLow= and DefaultMemoryMin=, which can be used to
@ -70,13 +70,13 @@ CHANGES WITH 243 in spe:
* Man pages are not built by default anymore (html pages were already
disabled by default), to make development builds quicker. When
building systemd for a full installation with documentation, meson
should be called with -Dman=true and/or -Dhtml=true as
appropriate. The default was changed based on the assumption that
quick one-off or repeated development builds are much more common
than full optimized builds for installation, and people need to pass
various other options to when doing "proper" builds anyway, so the
gain from making development builds quicker is bigger than the one
time disruption for packagers.
should be called with -Dman=true and/or -Dhtml=true as appropriate.
The default was changed based on the assumption that quick one-off or
repeated development builds are much more common than full optimized
builds for installation, and people need to pass various other
options to when doing "proper" builds anyway, so the gain from making
development builds quicker is bigger than the one time disruption for
packagers.
Two scripts are created in the *build* directory to generate and
preview man and html pages on demand, e.g.:
@ -85,7 +85,7 @@ CHANGES WITH 243 in spe:
build/man/html systemd.index
* libidn2 is used by default if both libidn2 and libidn are installed.
Please use -Dlibidn=true when libidn is favorable.
Please use -Dlibidn=true if libidn is preferred.
* The D-Bus "wire format" of the CPUAffinity= attribute is changed on
big-endian machines. Before, bytes were written and read in native
@ -105,11 +105,6 @@ CHANGES WITH 243 in spe:
long number (with the length varying by architecture), so they can be
unambiguously distinguished.
* SuccessExitStatus=, RestartPreventExitStatus=, and
RestartForceExitStatus= now accept exit status names (e.g. "DATAERR"
is equivalent to "65"). systemd-analyze learnt a new 'exit-status'
verb to display those exit status name mappings.
* /usr/sbin/halt.local is no longer supported. Implementation in
distributions was inconsistent and it seems this functionality was
very rarely used.
@ -151,7 +146,7 @@ CHANGES WITH 243 in spe:
* Services may now send a special WATCHDOG=trigger message with
sd_notify() to trigger an immediate "watchdog missed" event, and thus
request service take down. This is useful both for testing watchdog
trigger service termination. This is useful both for testing watchdog
handling, but also for defining error paths in services, that shall
be handled the same way as watchdog events.
@ -196,14 +191,20 @@ CHANGES WITH 243 in spe:
* systemd-resolved "Cache=" configuration option in resolved.conf has
been extended to also accept the 'no-negative' value. Previously,
only a boolean option was allowed (yes/no), having yes as the
default. If this option is set to 'no-negative', negative answers
are skipped from being cached while keeping the same cache heuristics
for positive answers. The default remains as "yes" (i.e. caching is
enabled).
default. If this option is set to 'no-negative', negative answers are
not cached while the old cache heuristics are used positive answers.
The default remains unchanged.
* The predictable naming scheme for network devices now supports
generating predictable names for "netdevsim" devices.
Moreover, the "en" prefix was dropped from the ID_NET_NAME_ONBOARD
udev property.
Those two changes form a new net.naming-policy-scheme= entry.
Distributions which want to preserve naming stability may want to set
the -Ddefault-net-naming-scheme= configuration option.
* systemd-networkd now supports MACsec, nlmon, IPVTAP and Xfrm
interfaces natively.
@ -267,6 +268,9 @@ CHANGES WITH 243 in spe:
SpeedMeterIntervalSec=, to measure bitrate of network interfaces. The
measured speed may be shown by 'networkctl status'.
* "networkctl status" now displays MTU and queue lengths, and more
detailed information about VXLAN and bridge devices.
* systemd-networkd's .network and .link files gained a new Property=
setting in the [Match] section, to match against devices with
specific udev properties.
@ -281,39 +285,55 @@ CHANGES WITH 243 in spe:
* A new tool systemd-network-generator has been added that may generate
.network, .netdev and .link files from IP configuration specified on
the kernel command line, compatible with the format Dracut expects.
the kernel command line in the format used by Dracut.
* The CriticalConnection= setting in .network files is now deprecated,
and replaced by a new KeepConfiguration= setting which allows more
detailed configuration of the IP configuration to keep in place.
* systemd-analyze gained a new "timestamp" verb for parsing and
converting timestamps. It's similar to the existing "systemd-analyze
calendar" command which does the same for recurring calendar
events. It also gained a new "condition" verb for parsing and testing
ConditionXYZ= expressions.
* systemd-analyze gained a few new verbs:
- "systemd-analyze timestamp" parses and converts timestamps. This is
similar to the existing "systemd-analyze calendar" command which
does the same for recurring calendar events.
- "systemd-analyze timespan" parses and converts timespans (i.e.
durations as opposed to points in time).
- "systemd-analyze condition" will parse and test ConditionXYZ=
expressions.
- "systemd-analyze exit-status" will parse and convert exit status
codes to their names and back.
- "systemd-analyze unit-files" will print a list of all unit
file paths and unit aliases.
* SuccessExitStatus=, RestartPreventExitStatus=, and
RestartForceExitStatus= now accept exit status names (e.g. "DATAERR"
is equivalent to "65"). Those exit status name mappings may be
displayed with the sytemd-analyze exit-status verb describe above.
* systemd-logind now exposes a per-session SetBrightness() bus call,
which may be used to securely change the brightness of a kernel
brightness device, if it belongs to the session's seat. By using this
call unprivileged clients can make changes to "backlight" and "leds"
devices securely with strict requirements on session
membership. Desktop environments may use this to generically make
brightness changes to such devices without shipping private SUID
binaries or specific udev rules for that purpose.
devices securely with strict requirements on session membership.
Desktop environments may use this to generically make brightness
changes to such devices without shipping private SUID binaries or
udev rules for that purpose.
* "udevadm info" gained a --wait-for-initialization switch to wait for
a device to be initialized.
* systemd-hibernate-resume-generator will now look for resumeflags= on
the kernel command line, which is similar to rootflags= and may be
used to configure device timeouts for waiting for the hibernation
device to show up.
used to configure device timeout for the hibernation device.
* sd-event learnt a new API call sd_event_source_disable_unref() for
disabling and unref'ing an event source in a single function. A
related call sd_event_source_disable_unrefp() has been added for use
with GCC's cleanup extension.
with gcc's cleanup extension.
* The sd-id128.h public API gained a new definition
SD_ID128_UUID_FORMAT_STR for formatting a 128bit ID in UUID format
@ -328,27 +348,26 @@ CHANGES WITH 243 in spe:
kernel command line option systemd.status_unit_format=.
* PID 1 now understands a new option KExecWatchdogSec= in
/etc/systemd/system.conf. It allows configuration of a watchdog
timeout to write to a hardware watchdog device on kexec-based
reboots. Previously this functionality was only available for regular
reboots. This option defaults to off, since it depends on drivers and
software setup whether the watchdog is correctly reset again after
the kexec completed, and thus for the general case not clear if safe
(since it might cause unwanted watchdog reboots after the kexec
completed otherwise). Moreover, the old ShutdownWatchdogSec= setting
has been renamed to RebootWatchdogSec= to more clearly communicate
what it is about. The old name of the setting is still accepted for
compatibility.
/etc/systemd/system.conf to set a watchdog timeout for kexec reboots.
Previously watchdog functionality was only available for regular
reboots. The new setting defaults to off, because we don't know in
the general case if the watchdog will be reset after kexec (some
drivers do reset it, but not all), and the new userspace might not be
configured to handle the watchdog.
Moreover, the old ShutdownWatchdogSec= setting has been renamed to
RebootWatchdogSec= to more clearly communicate what it is about. The
old name is still accepted for compatibility.
* The systemd.debug_shell kernel command line option now optionally
takes a tty name to spawn the debug shell on, which allows selecting
a different tty than the built-in default.
takes a tty name to spawn the debug shell on, which allows a
different tty to be selected than the built-in default.
* Service units gained a new ExecCondition= setting which will run
before ExecStartPre= and either continue execution of the unit (for
clean exit codes), stop execution without marking the unit failed
(for exit codes 1 through 254), or stop execution and fail the unit
(for exit code 255 or cases of abnormal termination).
(for exit code 255 or abnormal termination).
* A new service systemd-pstore.service has been added that pulls data
from /sys/fs/pstore/ and saves it to /var/lib/pstore for later
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true for the service to enable this behaviour, but please consult the
documentation first, since this comes with a couple of caveats.
* systemd-random-seed.service is now a synchronization point for the
point in time where the kernel's entropy pool is fully
initialized. Order services that require /dev/urandom to be correctly
initialized after this service.
* systemd-random-seed.service is now a synchronization point for full
initialization of the kernel's entropy pool. Services that require
/dev/urandom to be correctly initialized should be ordered after this
service.
* The systemd-boot boot loader has been updated to optionally maintain
a random seed file in the EFI System Partition (ESP). During the boot
phase, this random seed is read and updated with a new seed
crytographically derived from it. Another derived seed is passed to
cryptographically derived from it. Another derived seed is passed to
the OS. The latter seed is then credited to the kernel's entropy pool
very early during userspace initialization (from PID 1). This allows
systems to boot up with a fully initialized kernel entropy pool from
earliest boot on, and thus entirely removes all entropy pool
initialization delays from systems using systemd-boot. Special care
is taken to ensure different seeds are derived on system images
replicated to multiple systems.
replicated to multiple systems. "bootctl status" will show whether
a seed was received from the boot loader.
* bootctl gained a new verb "is-installed" that checks whether
systemd-boot is currently installed.
* bootctl gained two new verbs:
- "bootctl random-seed" will generate the file in ESP and an EFI
variable to allow a random seed to be passed to the OS as described
above.
- "bootctl is-installed" checks whether systemd-boot is currently
installed.
* bootctl will warn if it detects that boot entries are misconfigured
(for example if the kernel image was removed without purging the
bootloader entry).
* A new document has been added describing systemd's use and support
for the kernel's entropy pool subsystem: