systemd是一个init程序。根据之前 Upstart的一些介绍大家应该简要了解了传统Sysvinit系统的不足之处。不过，这次的systemd的设计思想更为超前，也可以说是借鉴了OSX上launchd的思路。 systemd 219 发布，此版本包括大量的改进，特别是容器，btrfs，hookup 和网络模块，同时也有大量的 bug 修复，Enjoy！ 此版本现已提供下载： http://www.freedesktop.org/software/systemd/systemd-219.tar.xz 注意，此版本还未提供在 Fedora F22/F23。 更新内容： * Introduce a new API "sd-hwdb.h" for querying the hardware metadata database. * When any of systemd's tools copies files (for example due to tmpfiles' C lines) a btrfs reflink will attempted first, before bytewise copying is done. * systemd-nspawn gained a new --ephemeral switch. * systemd-nspawn gained a new --template= switch. * When a .mount unit refers to a mount point on which multiple mounts are stacked, and the .mount unit is stopped all of the stacked mount points will now be unmounted until no mount point remains. * systemd now has an explicit notion of supported and unsupported unit types. * machinectl gained support for two new "copy-from" and "copy-to" commands for copying files from a running container to the host or vice versa. * machinectl gained support for a new "bind" command to bind mount host directories into local containers. This is currently only supported for nspawn containers. * networkd gained support for configuring bridge forwarding database entries (fdb) from .network files. * A new tiny daemon "systemd-importd" has been added that can download container images in tar, raw, qcow2 or dkr formats, and make them available locally in /var/lib/machines, so that they can run as nspawn containers. The daemon can GPG verify the downloads (not supported for dkr, since it has no provisions for verifying downloads). * machinectl is now able to list container images found in /var/lib/machines, along with some metadata about sizes of disk and similar. * machinectl is now able to clone container images efficiently, if the underlying file system (btrfs) supports it, with the new "machinectl list-images" command. * networkd gained support for collecting LLDP network announcements, from hardware that supports this. This is shown in networkctl output. * systemd-run gained support for a new -t (--pty) switch for invoking a binary on a pty whose input and output is connected to the invoking terminal. * tmpfiles gained support for a new "v" line type for creating btrfs subvolumes. * The directory /var/lib/containers/ has been deprecated and been replaced by /var/lib/machines. * systemd-nspawn when invoked with -M but without --directory= or --image= is now capable of searching for the container root directory, subvolume or disk image automatically, in /var/lib/machines. * A new machines.target unit has been introduced that is supposed to group all containers/VMs invoked as services on the system. * machinectl gained a new "start" command, for invoking a container as a service. * systemd-nspawn will now mount most of the cgroupfs tree read-only into each container, with the exception of the container's own subtree in the name=systemd hierarchy. * journald now sets the special FS_NOCOW file flag for its journal files. * When journald detects that journal files it is writing to have been deleted it will immediately start new journal files. * systemd now provides a way to store file descriptors per-service in PID 1. * The default TERM variable to use for units connected to a terminal, when no other value is explicitly is set is now vt220 rather than vt102. This should be fairly safe still, but allows PgUp/PgDn work. * The /etc/crypttab option header= as known from Debian is now supported. * "loginctl user-status" and "loginctl session-status" will now show the last 10 lines of log messages of the user/session following the status output. Similar, "machinectl status" will show the last 10 log lines associated with a virtual machine or container service. * "loginctl session-status" without further argument will now show the status of the session of the caller. * An X11 session scriptlet is now shipped that uploads $DISPLAY and $XAUTHORITY into the environment of the systemd --user daemon if a session begins. * Generators are now subject to masking via /etc and /run, the same way as unit files. * networkd .network files gained support for configuring per-link IPv4/IPv6 packet forwarding as well as IPv4 masquerading. * systemd-nspawn gained the --port= (-p) switch to expose TCP or UDP posts of a container on the host. * systemd-nspawn's --network-veth switch now gained a short version "-n", since with the changes above it is now truly useful out-of-the-box. * systemd-nspawn will now maintain a per-image R/W lock, to ensure that the same image is not started more than once writable. (It's OK to run an image multiple times simultaneously in read-only mode.) * systemd-nspawn's --image= option is now capable of dissecting and booting MBR and GPT disk images that contain only a single active Linux partition. * In addition to collecting mouse dpi data in the udev hardware database, there's now support for collecting angle information for mouse scroll wheels. * udev's input_id built-in will now also collect touch screen dimension data and attach it to probed devices. * /etc/os-release gained support for a Distribution Privacy Policy link field. * networkd gained support for creating "ipvlan", "gretap", "ip6gre", "ip6gretap" and "ip6tnl" network devices. * systemd-tmpfiles gained support for "a" lines for setting ACLs on files. * systemd-nspawn will now mount /tmp in the container to tmpfs, automatically. * systemd now exposes the memory.usage_in_bytes cgroup attribute and shows it for each service in the "systemctl status" output, if available. * When the user presses Ctrl-Alt-Del more than 7x within 2s an immediate reboot is triggered. * A .device unit for an optical block device will now be considered active only when a medium is in the drive. * networkd-wait-online now has support for waiting for specific interfaces only (with globbing), and for giving up after a configurable timeout. * networkd now exits when idle. It will be automatically restarted as soon as interfaces show up, are removed or change state. * networkd may now configure IPv6 link-local addressing in addition to IPv4 link-local addressing. * The IPv6 "token" for use in SLAAC may now be configured for each .network interface in networkd. * Routes configured with networkd may now be assigned a scope in .network files. * networkd's [Match] sections now support globbing and lists of multiple space-separated matches per item. 更多更新内容请看发行说明。 systemd 219 发布，Linux 的 init 程序下载地址
