使用 linux 時經(jīng)常用到 ` service MySQL restart ` 等命令, 方便進行服務的操作, 具體的服務是怎么寫的呢,通過以下示例將了解以下內(nèi)容:
- 如何寫一個簡單的服務
- 服務異常關閉時能自動開啟配置
簡單的示例
nano /lib/systemd/system/xx.service
[Unit]
Description=Check GPU INFO by chenwei # 服務描述
Wants=network-online.target # 服務依賴于網(wǎng)絡
After=network-online.target
[Service]
Type=simple
ExecStart=/root/shell/agent/chkgpu # 服務開啟時執(zhí)行腳本
ExecReload=/bin/kill -HUP $MAINPID # 服務重新加載時執(zhí)行腳本
RestartSec=5s # 自動啟動間隔時間
Restart=on-failure # 在什么情況下會自動重啟
[Install]
WantedBy=multi-user.target
[Unit]
Description=Advanced key-value store
After=network.target
[Service]
Type=forking
ExecStart=/usr/local/redis/bin/redis-server /usr/local/redis/etc/redis.conf
ExecStop=/bin/kill -s TERM $MAINPID
PIDFile=/var/run/redis_6379.pid
Restart=always
RestartSec=5s
Restart=on-failure
[Install]
WantedBy=multi-user.target
Alias=redis.service
Nginx 示例
[Unit]
Description=A high performance web server and a reverse proxy server
After=network.target
[Service]
Type=forking
PIDFile=/var/run/nginx.pid
#ExecStartPre=/usr/local/nginx/sbin/nginx
ExecStart=/usr/sbin/nginx
ExecReload=/usr/sbin/nginx -s reload
ExecStop=-/sbin/start-stop-daemon --quiet --stop --retry QUIT/5 --pidfile /run/nginx.pid
TimeoutStopSec=5
KillMode=mixed
[Install]
WantedBy=multi-user.target
常用命令
systemctl enable --now nginx.service # 立刻開啟并開機啟動
systemctl daemon-reload #重新加載
systemctl enable nginx.service #開機時啟動
systemctl disable nginx.service #開機時禁用
systemctl list-unit-files|grep enabled #已啟動服務列表
systemctl --failed #啟動失敗服務列表
sudo update-rc.d nginx defaults #開機時啟動
wssh
file=/lib/systemd/system/myssh.service mv $file $file.bak cat «EOF »$file
[Unit] Description=Web SSH server by chenwei. pip install webssh Wants=network-online.target
After=network-online.target
[Service] Type=simple ExecStart=wssh ExecReload=/bin/kill -HUP $MAINPID
RestartSec=5s
Restart=on-failure
[Install] WantedBy=multi-user.target
EOF cat $file
issh
file=/usr/bin/issh
mv $file $file.bak
cat <<EOF >>$file
#!/bin/bash
wssh
autossh -M 10111 -NR 0.0.0.0:11111:localhost:22 pc@1.10sh.cn
EOF
cat $file
chmod +x $file
file=/lib/systemd/system/issh.service
mv $file $file.bak
cat <<EOF >>$file
[Unit]
Description=autossh shell to connect to my server by chenwei. #sudo apt install autossh
Wants=network-online.target
After=network-online.target
[Service]
Type=simple
ExecStart=/usr/bin/issh
ExecReload=/bin/kill -HUP
RestartSec=5s
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF
cat $file
systemctl enable --now issh.service
systemctl status issh.service
pweb
使用Python 啟動一個簡單的 http 文件服務
sudo -i
file=/home/pweb.sh
mv $file $file.bak
cat <<EOF >>$file
#!/bin/bash
python3 -m http.server
EOF
cat $file
chmod +x $file
file=/lib/systemd/system/pweb.service
mv $file $file.bak
cat <<EOF >>$file
[Unit]
Description=Simple python pweb by chenwei.
Wants=network-online.target
After=network-online.target
[Service]
Type=simple
ExecStart=/home/pweb.sh
ExecReload=/bin/kill -HUP
RestartSec=5s
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF
cat $file
systemctl enable --now pweb.service
systemctl status pweb.service
