/lib/systemd/system
/run/systemd/system
/etc/systemd/system

[Unit]

Description=nginx - high performance web server

Documentation=http://nginx.org/en/docs/

After=network.target remote-fs.target nss-lookup.target

[Service]

Type=forking

PIDFile=/usr/local/nginx/logs/nginx.pid

ExecStartPre=/usr/local/nginx/sbin/nginx -t -c /usr/local/nginx/conf/nginx.conf

ExecStart=/usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf

ExecReload=/bin/kill -s HUP $MAINPID

ExecStop=/bin/kill -s QUIT $MAINPID

PrivateTmp=true

[Install]

WantedBy=multi-user.target

systemctl enable nginx.service

# 自启动
systemctl enable nginx.service

# 禁止自启动
systemctl disable nginx.service

# 启动服务
systemctl start nginx.service

# 停止服务
systemctl stop nginx.service

# 重启服务
systemctl restart nginx.service

# 查看Unit定义文件
systemctl cat nginx.service

# 编辑Unit定义文件
systemctl edit nginx.service

# 重新加载Unit定义文件
systemctl reload nginx.service

# 列出已启动的所有unit，就是已经被加载到内存中
systemctl list-units

# 列出系统已经安装的所有unit，包括那些没有被加载到内存中的unit
systemctl list-unit-files

# 查看服务的日志
journalctl -u nginx.service # 还可以配合`-b`一起使用，只查看自本次系统启动以来的日志

# 查看所有target下的unit
systemctl list-unit-files --type=target

# 查看默认target，即默认的运行级别。对应于旧的`runlevel`命令
systemctl get-default

# 设置默认的target
systemctl set-default multi-user.target

# 查看某一target下的unit
systemctl list-dependencies multi-user.target

# 切换target，不属于新target的unit都会被停止
systemctl isolate multi-user.target
systemctl poweroff # 关机
systemctl reboot  # 重启
systemctl rescue # 进入rescue模式

package main

import (
 "flag"
 "fmt"
 "log"
 "net/http"
)

func main() {
 var address string
 flag.StringVar(&address, "address", "5353", "listen address")
 flag.Parse()

 http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
  fmt.Fprintf(w, "Hello, This is a test for systemd !\n")
 }) // 设置访问路由

 log.Printf("Starting server on %s\n", address)
 log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", address), nil))
}

CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o systemd-test main.go
rsync -zP ./systemd-test root@gp-aliyun:/usr/local/bin/

[Unit]
Description=Systemd Test
After=network.target

[Service]
User=nobody
# Execute `systemctl daemon-reload` after ExecStart= is changed.
ExecStart=/usr/local/bin/systemd-test -address "6060"
[Install]
WantedBy=multi-user.target

# 每一次修改ExecStart都需执行
systemctl daemon-reload
# 启动
systemctl start systemd-test.service
# 查看状态
systemctl status systemd-test.service