systemd.md

systemd

Global Environment

config file will set default environment variables for all systemd units.

• /etc/systemd/system.conf.d/10-default-env.conf

[Manager]
DefaultEnvironment=DEFAULT_IPV4=192.168.10.51 
DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"

User Environment

set environment variables for all users logged in Container Linux.

• /etc/profile.env

export HTTP_PROXY=http://192.168.0.1:3128

Show Environemnt

systemctl show-environment

Reload Environment

systemctl   daemon-reexec 

• Refer stemd-system.conf
• Refer using environment variables in systemd units
• CHAPTER 6. MANAGING SERVICES WITH SYSTEMD

timer

mysql-backup-full.service

[Unit]
Description=full backup for mysql-1
After=mysql-1.service
[Service]
Type=oneshot
ExecStartPre=-/bin/bash -c '/bin/mkdir -p /hdd1/mysql-backup/data'
ExecStartPre=-/bin/bash -c '/bin/mv /hdd1/mysql-backup/data /hdd1/mysql-backup/data-$$(date +%%Y%%m%%d-%%H%%M%%S)'
ExecStart=/bin/bash -c "/usr/bin/docker run --rm \
-v /hdd1/mysql:/var/lib/mysql \
-v /hdd1/mysql-backup/data:/backup \
perconalab/percona-xtrabackup xtrabackup --compress --backup --host= --port= --user= --password= --target-dir=/backup/base"

[Install]
WantedBy=multi-user.target

mysql-backup-full.timer

[Unit]
Description=full backup mysql every week

[Timer]
OnBootSec=200
RandomizedDelaySec=100
OnCalendar=Sun *-*-* 00:10:05
Persistent=true

[Install]
WantedBy=timers.target

systemctl enable --now mysql-backup-full.timer
systemctl enable --now mysql-backup-full.service
systemctl start mysql-backup-full.service
systemctl start mysql-backup-full.timer
systemctl list-timers --all

OnCalender values:

minutely
hourly
daily
monthly
weekly
yearly
quarterly
semiannually

• Calendar Usage
• Systemd 入门教程：实战篇
• Systemd 定时器教程
• Systemd 定时器教程
• Creating A Timer
• Timers (简体中文)