Systemd: Difference between revisions
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= Documentation = | = Documentation = | ||
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*[[https://blog.darknedgy.net/technology/2020/05/02/0/index.html#tech-critique https://blog.darknedgy.net/technology/2020/05/02/0/index.html#tech-critique] | *[[https://blog.darknedgy.net/technology/2020/05/02/0/index.html#tech-critique https://blog.darknedgy.net/technology/2020/05/02/0/index.html#tech-critique] | ||
*[https://mohsensy.github.io/sysadmin/2018/08/19/systemd-service-tutorial.html Systemd service tutorial] | *[https://mohsensy.github.io/sysadmin/2018/08/19/systemd-service-tutorial.html Systemd service tutorial] | ||
*[https://www.freedesktop.org/wiki/Software/systemd/dbus/ https://www.freedesktop.org/wiki/Software/systemd/dbus/ Systemd and dbus] | |||
*[https://www.thegeekdiary.com/how-to-boot-into-rescue-mode-or-emergency-mode-through-systemd-in-centos-rhel-7-and-8/ Single user/emergency] | |||
= Locations = | = Locations = | ||
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systemctl list-timers | systemctl list-timers | ||
=== List | |||
=== List all timers === | |||
systemctl list-timers --all | systemctl list-timers --all | ||
=== Create timer === | === Create timer === | ||
systemctl enable fstrim.timer | systemctl enable fstrim.timer | ||
== Auto restart crashed services == | |||
systemctl edit elasticsearch.service | |||
add: | |||
[Service] | |||
Restart=always | |||
then | |||
systemctl daemon-reload | |||
systemctl restart elasticsearch.service | |||
And to get an email when service gets restarted: https://dev.to/setevoy/linux-systemd-unit-files-edit-restart-on-failure-and-email-notifications-5h3k | |||
= FAQ = | = FAQ = | ||
== Fix journal size == | |||
journalctl --vacuum-time=10d | |||
or | |||
journalctl --vacuum-size=1G | |||
===Journal settings=== | |||
/etc/systemd/journald.conf | |||
SystemMaxUse=1G | |||
and then | |||
systemctl restart systemd-journald.service | |||
== Analyze boot processes == | == Analyze boot processes == | ||
systemd-analyze blame | systemd-analyze blame | ||
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resolvectl status | resolvectl status | ||
=== Failed to get global data: Unit dbus-org.freedesktop.resolve1.service not found. === | |||
Means systemd-resolved is not running | |||
Restart: | Restart: | ||
systemctl restart systemd-resolved | systemctl restart systemd-resolved | ||
| |||
=== Add nameserver === | |||
Sacrifice a chicken | |||
| |||
=== Flush caches === | |||
systemd-resolve --flush-caches | |||
== All status == | == All status == | ||
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systemctl daemon-reexec | systemctl daemon-reexec | ||
==Status== | |||
=== Active: inactive (dead) === | |||
parameter ActiveState would return inactive | |||
SubState returns dead | |||
Revision as of 20:36, 20 May 2022
Documentation
- Useful systemd commands
- http://www.freedesktop.org/wiki/Software/systemd/
- https://wiki.ubuntu.com/systemd
- Creating systemd service
- https://wiki.ubuntu.com/SystemdForUpstartUsers
- How To Use Systemctl to Manage Systemd Services and Units
- How to switch from NetworkManager to systemd-networkd on Linux
- https://fedoraproject.org/wiki/SysVinit_to_Systemd_Cheatsheet
- Predictable Network Interface Names
- [https://blog.darknedgy.net/technology/2020/05/02/0/index.html#tech-critique
- Systemd service tutorial
- https://www.freedesktop.org/wiki/Software/systemd/dbus/ Systemd and dbus
- Single user/emergency
Locations
/etc/systemd /usr/lib/systemd/ /lib/systemd
HOWTO
Timers
man systemd.timer
List active timers
systemctl list-timers
List all timers
systemctl list-timers --all
Create timer
systemctl enable fstrim.timer
Auto restart crashed services
systemctl edit elasticsearch.service
add:
[Service] Restart=always
then
systemctl daemon-reload systemctl restart elasticsearch.service
And to get an email when service gets restarted: https://dev.to/setevoy/linux-systemd-unit-files-edit-restart-on-failure-and-email-notifications-5h3k
FAQ
Fix journal size
journalctl --vacuum-time=10d
or
journalctl --vacuum-size=1G
Journal settings
/etc/systemd/journald.conf
SystemMaxUse=1G
and then
systemctl restart systemd-journald.service
Analyze boot processes
systemd-analyze blame
Systemd and DNS
resolvectl status
Failed to get global data: Unit dbus-org.freedesktop.resolve1.service not found.
Means systemd-resolved is not running
Restart:
systemctl restart systemd-resolved
Add nameserver
Sacrifice a chicken
Flush caches
systemd-resolve --flush-caches
All status
systemctl status -a
syslog spam
list available services
systemctl list-unit-files
or
systemctl list-units
normal interface names
net.ifnames=0
Show failed services
systemctl --failed
systemd: Started Session
Change loglevel to notice in /etc/systemd/system.conf
systemctl daemon-reexec
Status
Active: inactive (dead)
parameter ActiveState would return inactive
SubState returns dead
