Systemd
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Replaces initd. It should be more efficient. Honestly I don't see the benefits.
The service command invoke script in /etc/init.d.
- service --status-all
- Run all scripts with the 'status' option. Tells you which services are up.
It also provides timed execution like cron does equally well.
- systemctl list-timers
- Show all active timers
E.g for certbot (letsencrypt)
$ systemctl list-timers
NEXT LEFT LAST PASSED UNIT ACTIVATES
do 2018-11-29 00:00:00 CET 2h 5min left wo 2018-11-28 12:00:01 CET 9h ago certbot.timer certbot.service
2 timers listed.
Pass --all to see loaded but inactive timers, too.
$ cat /lib/systemd/system/certbot.timer
[Unit]
Description=Run certbot twice daily
[Timer]
OnCalendar=*-*-* 00,12:00:00
Persistent=true
[Install]
WantedBy=timers.target
$ cat /lib/systemd/system/certbot.service
[Unit]
Description=Certbot
Documentation=file:///usr/share/doc/python-certbot-doc/html/index.html
Documentation=https://letsencrypt.readthedocs.io/en/latest/
[Service]
Type=oneshot
ExecStartPre=/usr/bin/perl -e 'sleep int(rand(3600))'
ExecStart=/usr/bin/certbot -q renew
PrivateTmp=true
- systemctl daemon-reload
- After changing a configuration file reload it
- systemctl mask UNIT>
- Link the timer to /dev/null effectively disabling it