Systemd Init System
Last updated: Oct 16, 2019
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- Desktop Bus
- S/w bus for communication b/w processes using IPC and RPC
- D-bus wire protocol allows connection b/w various processes using unix domain sockets
:1.1557unique process address
How to configure network using systemd?
networkd to configure netwrok interfaces.
Configuration file path
initsystem for linux
- System and service Manager
- controls machine boot
- recplaces lots of shell scripts for system boot
- Software platform for developing other apps
- Glue between user and kernel spacce applications
- Resources are called
Units, it manages them in dependency graph.
Seperate bootstrap scripts
one-shotapplications on various cloud environments.
[Match] Name=en* [Network] Address=192.168.0.15/24 Gateway=192.168.0.1 # OR DHCP=yes
- send alerts from terminal commands/scripts
timesyncd daemon which requires linux user and group by name
systemd-timesync to be present on system.
It synchronizes system clock across the network
- timedatectl list-timezones
- set system time and zone settings
This file contains the timestamp of the last successful synchronization.
systemctl status systemd-timedated.service bat /lib/systemd/system/systemd-timedated.service localectl timedatectl status
Disable timwsyncd service in yocto
To disable timesyncd in your Yocto build, create a *.bbappend recipe in your own layer called
recipes-core/systemd/systemd_216.bbappend And add the following content PACKAGECONFIG[timesyncd] = "--enable-timesyncd,--disable-timesyncd,timesyncd" PACKAGECONFIG_remove = "timesyncd"
Systemd vs Supervisord
Let’s say I have a Django application named Foo. I want to be sure Foo is running all the time, even if it crashes. Also, I want a simple interface to start, stop and restart its process. Supervisord is a perfect match for this job.
- Process Monitoring
- systemd has not, like controlling services with a web interface
- Project Cockpit1 interactive server admin interface
Cockpit uses systemd and the DBus APIs it provides to configure and monitor core aspects of the system.
[Unit] Description="Foo web application" After=network.target [Service] User=foo Group=foo Environment=LANG=en_US.UTF-8,LC_ALL=en_US.UTF-8 ExecStart=/home/foo/bin/start_foo [Install] WantedBy=multi-user.target
LC_ALL: cannot change locale
sudo locale-check sudo locale-gen en_US sudo update-locale LANG=en_US