Systemd: Difference between revisions
From DWIKI
mNo edit summary |
m (→Flush caches) |
||
| (19 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
| | ||
= Documentation = | = Documentation = | ||
| Line 15: | Line 16: | ||
*[[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 = | ||
| Line 28: | Line 29: | ||
= HOWTO = | = HOWTO = | ||
==systemctl verbose== | |||
SYSTEMD_LOG_LEVEL=debug systemctl start yourservice | |||
==Services== | |||
===List enabled services=== | |||
See https://www.baeldung.com/linux/systemctl-list-enabled-services | |||
systemctl list-unit-files --state=enabled | |||
===Edit systemd service file=== | |||
systemctl edit --full my.service | |||
== Timers == | == Timers == | ||
| Line 33: | Line 45: | ||
*[https://opensource.com/article/20/7/systemd-timers https://opensource.com/article/20/7/systemd-timers] | *[https://opensource.com/article/20/7/systemd-timers https://opensource.com/article/20/7/systemd-timers] | ||
*[https://wiki.archlinux.org/title/Systemd/Timers https://wiki.archlinux.org/title/Systemd/Timers] | *[https://wiki.archlinux.org/title/Systemd/Timers https://wiki.archlinux.org/title/Systemd/Timers] | ||
*https://linuxhint.com/cron_systemd_timer/ also about random time | |||
man systemd.timer | man systemd.timer | ||
| Line 45: | Line 57: | ||
systemctl list-timers --all | systemctl list-timers --all | ||
=== | === Enable 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 | |||
==Logs== | |||
===View systemd logs=== | |||
journalctl -u postfix | |||
= FAQ = | = FAQ = | ||
| Line 55: | Line 84: | ||
systemd-analyze blame | systemd-analyze blame | ||
== gateway4 has been deprecated == | |||
Using routes: | |||
routes: | |||
- to: default | |||
via: 192.168.1.1 | |||
== Systemd and DNS == | == Systemd and DNS == | ||
resolvectl status | resolvectl status | ||
===Change nameserversers resolvectl uses=== | |||
====On Ubuntu==== | |||
Edit the netplan file | |||
netplan generate | |||
netplan apply | |||
=== Failed to get global data: Unit dbus-org.freedesktop.resolve1.service not found. === | |||
Means systemd-resolved is not running | |||
Restart: | Restart: | ||
| Line 67: | Line 110: | ||
| |||
=== Add nameserver === | === Add nameserver === | ||
Sacrifice a chicken | Sacrifice a chicken | ||
| |||
=== Flush caches === | |||
# thing from the past? | |||
systemd-resolve --flush-caches | |||
== All status == | == All status == | ||
| Line 104: | Line 156: | ||
systemctl daemon-reexec | systemctl daemon-reexec | ||
==Status== | |||
=== Active: inactive (dead) === | |||
parameter ActiveState would return inactive | |||
SubState returns dead | |||
Latest revision as of 16:30, 21 November 2024
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
systemctl verbose
SYSTEMD_LOG_LEVEL=debug systemctl start yourservice
Services
List enabled services
See https://www.baeldung.com/linux/systemctl-list-enabled-services
systemctl list-unit-files --state=enabled
Edit systemd service file
systemctl edit --full my.service
Timers
- https://opensource.com/article/20/7/systemd-timers
- https://wiki.archlinux.org/title/Systemd/Timers
- https://linuxhint.com/cron_systemd_timer/ also about random time
man systemd.timer
List active timers
systemctl list-timers
List all timers
systemctl list-timers --all
Enable 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
Logs
View systemd logs
journalctl -u postfix
FAQ
Analyze boot processes
systemd-analyze blame
gateway4 has been deprecated
Using routes:
routes: - to: default via: 192.168.1.1
Systemd and DNS
resolvectl status
Change nameserversers resolvectl uses
On Ubuntu
Edit the netplan file
netplan generate netplan apply
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
- thing from the past?
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
