Difference between revisions of "Systemd"
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$ systemctl [status|stop|enable|disable|restart] ssh.service | $ systemctl [status|stop|enable|disable|restart] ssh.service | ||
$ systemctl is-enabled ssh.service | $ systemctl is-enabled ssh.service | ||
| + | $ systemctl cat ssh.service | ||
$ systemctl [reboot|poweroff|suspend] | $ systemctl [reboot|poweroff|suspend] | ||
Revision as of 19:56, 6 November 2015
systemd is a suite of system management daemons, libraries, and utilities designed as a central management and configuration platform for the Linux computer operating system.
Contents
Example usage
- Check if you are running "init" or "systemd":
$ cat /proc/1/comm systemd
- Restart network:
$ systemctl restart network.target
- stop and mask the firewalld service (see: iptables vs. firewalld):
$ systemctl stop firewalld $ systemctl mask firewalld
- Miscellaneous:
$ systemctl list-units $ systemctl list-units -t service $ systemctl list-units | grep .service $ systemctl list-units -t target $ systemctl list-unit-files $ systemctl list-unit-files -t target $ systemctl list-dependencies multi-user.target $ systemctl [status|stop|enable|disable|restart] ssh.service $ systemctl is-enabled ssh.service $ systemctl cat ssh.service $ systemctl [reboot|poweroff|suspend]
$ systemctl --failed UNIT LOAD ACTIVE SUB DESCRIPTION ● pollinate.service loaded failed failed Seed the pseudo random number generator on first boot ● vboxadd.service loaded failed failed LSB: VirtualBox Linux Additions kernel modules LOAD = Reflects whether the unit definition was properly loaded. ACTIVE = The high-level unit activation state, i.e. generalization of SUB. SUB = The low-level unit activation state, values depend on unit type.
- cgroup tree
$ systemd-cgls ├─1 /sbin/init ├─system.slice │ ├─dbus.service │ │ └─776 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation │ ├─cron.service │ │ └─692 /usr/sbin/cron -f ...
- ps with cgroups:
$ alias psc='ps xawf -eo pid,user,cgroup,args'
Related commands
systemd-analyze
- Analyze system boot-up performance
$ systemd-analyze Startup finished in 5.223s (kernel) + 7.781s (userspace) = 13.004s
- Plot all dependencies of any unit whose name starts with "avahi-daemon":
$ systemd-analyze dot 'avahi-daemon.*' | dot -Tsvg > avahi.svg $ eog avahi.svg
- Plot the dependencies between all known target units:
$ systemd-analyze dot --to-pattern='*.target' --from-pattern='*.target' | dot -Tsvg > targets.svg $ eog targets.svg
journalctl
Note: combine with syslog-ng for backward compatibility.
$ journalctl $ journalctl | grep -Ei 'error|fail' $ journalctl -b # show only logs from this boot $ journalctl -b -1 # show only logs from previous boot $ journalctl -u ssh # show only logs for a given unit $ journalctl -f # follow (somewhat analogous to `tail -f /var/log/messages`) $ journalctl -f -u ssh.service # show only logs for ssh unit and follow
timedatectl
Note: Most of these commands will need to be run as either root or sudo and is only valid for systems using systemd.
- List all available timezones on your computer/server:
$ timedatectl list-timezones
- Set your computer's/server's timezone:
$ timedatectl set-timezone region/timezone
- For instance, to set your timezone to United States Pacific Time (PST; -8GMT):
$ timedatectl set-timezone America/Vancouver
Your system will be updated to use the selected timezone. You can verify with:
$ timedatectl
Local time: Fri, 2012-11-02 09:26:46 CET
Universal time: Fri, 2012-11-02 08:26:46 UTC
RTC time: Fri, 2012-11-02 08:26:45
Timezone: Europe/Warsaw
UTC offset: +0100
NTP enabled: no
NTP synchronized: no
RTC in local TZ: no
DST active: no
Last DST change: CEST → CET, DST became inactive
Sun, 2012-10-28 02:59:59 CEST
Sun, 2012-10-28 02:00:00 CET
Next DST change: CET → CEST, DST will become active
the clock will jump one hour forward
Sun, 2013-03-31 01:59:59 CET
Sun, 2013-03-31 03:00:00 CEST
- Enable an NTP daemon (chronyd):
$ timedatectl set-ntp true ==== AUTHENTICATING FOR org.freedesktop.timedate1.set-ntp === Authentication is required to control whether network time synchronization shall be enabled. Authenticating as: user Password: ******** ==== AUTHENTICATION COMPLETE === $ systemctl status chronyd.service chronyd.service - NTP client/server Loaded: loaded (/lib/systemd/system/chronyd.service; enabled) Active: active (running) since Fri, 2012-11-02 09:36:25 CET; 5s ago ...
hostnamectl
`hostnamectl` allows you to control the system hostname.
- Example response from a laptop running Ubuntu:
$ hostnamectl
Static hostname: my_hostname
Icon name: computer-laptop
Chassis: laptop
Boot ID: ffffffffffffffffffffffffffffffff
Operating System: Ubuntu 14.04.2 LTS
Kernel: Linux 3.13.0-52-generic
Architecture: x86_64
- Example response from a vagrant box running Fedora:
$ hostnamectl
Static hostname: localhost.localdomain
Icon name: computer-vm
Chassis: vm
Machine ID: ffffffffffffffffffffffffffffffff
Boot ID: ffffffffffffffffffffffffffffffff
Virtualization: oracle
Operating System: Fedora 22 (Twenty Two)
CPE OS Name: cpe:/o:fedoraproject:fedora:22
Kernel: Linux 4.0.4-303.fc22.x86_64
Architecture: x86-64
Other
See: for a complete list
- Control the system locale and keyboard layout settings:
$ localectl
System Locale: LANG=en_US.UTF-8
VC Keymap: n/a
X11 Layout: us
X11 Model: pc105
$ loginctl # Control the systemd login manager $ busctl # Introspect the bus $ machinectl # Control the systemd machine manager $ networkctl # Query the status of network links $ systemd-cgls # Recursively show control group contents $ systemd-cgtop # Show top control groups by their resource usage $ systemd-path # List and query system and user paths
