基于golang的systemd守护进程应用分析 - 熊喵君的博客

0x00 前言

场景如下：

服务开机启动
需要时刻监测某个重要服务是否在线，如果程序报错退出则自动重启服务，以此来保持服务常在线

systemd简介

1、基本操作，假设服务程序路径部署在/usr/local/bin/systemd-test，配置存储在/etc/systemd/system/systemd-test.service

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

[Service]
User=nobody
# Execute `systemctl daemon-reload` after ExecStart= is changed.
ExecStart=/usr/local/bin/systemd-test
[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

0x01 Nginx配置

0x02 两个例子

1、case1:

func PANIC() {
        time.Sleep(30 * time.Second)
        panic("PANIC")
}

func main() {
        l, err := net.Listen("tcp", ":8081")
        if err != nil {
                log.Panicf("cannot listen: %s", err)
        }

        go PANIC()

        http.Serve(l, nil) 
}

[root@VM-X-X-centos notify]# cat /etc/systemd/system/systemd-test.service 
[Unit]
Description=Systemd Test
After=network.target

[Service]
Type=simple
User=nobody
# Execute `systemctl daemon-reload` after ExecStart= is changed.
ExecStart=/usr/local/bin/systemd-test
Restart=on-failure
RestartSec=10
[Install]
WantedBy=multi-user.target

2、case2

func a() {
        for {
                _, err := http.Get("http://127.0.0.1:8081") // ❸
                if err == nil {
                        daemon.SdNotify(false, daemon.SdNotifyWatchdog)
                }
                time.Sleep(3 * time.Second)
        }
}

func b() {
        time.Sleep(30 * time.Second)
        panic("panic")
}

func main() {
        l, err := net.Listen("tcp", ":8081")
        if err != nil {
                log.Panicf("cannot listen: %s", err)
        }
        daemon.SdNotify(false, daemon.SdNotifyReady) 

        go a()

        go b()

        http.Serve(l, nil) 
}

[root@VM-X-X-centos notify]# cat /etc/systemd/system/systemd-test.service 
[Unit]
Description=Systemd Test
After=network.target

[Service]
Type=notify
User=nobody
# Execute `systemctl daemon-reload` after ExecStart= is changed.
ExecStart=/usr/local/bin/systemd-test
Restart=on-failure
RestartSec=10
[Install]
WantedBy=multi-user.target

0x0 参考

FEATURED TAGS

Latex gRPC 负载均衡 OpenSSH Authentication Consul Etcd Kubernetes 性能优化 Python 分布式锁 WebConsole 后台开发 Golang OpenSource Nginx Vault 网络安全 Perl 分布式理论 Raft 正则表达式 Redis 分布式限流 go-redis 微服务反向代理 ReverseProxy Cache 缓存连接池 OpenTracing GOMAXPROCS GoMicro 微服务框架日志 zap Pool Kratos Hystrix 熔断并发 Pipeline 证书 Prometheus Metrics PromQL Breaker 定时器 Timer Timeout Kafka Xorm MySQL Fasthttp bytebufferpool 任务队列队列异步队列 GOIM Pprof errgroup consistent-hash Zinx 网络框架设计模式 HTTP Gateway Queue Docker 网关 Statefulset NFS Machinery Teleport Zero Trust Oxy 存储 Confd 热更新 OAuth SAML OpenID Openssl AES 微服务网关 IM KMS 安全数据结构 hashtable Sort Asynq 基数树 Radix Crontab 热重启系统编程 sarama Go-Zero RDP VNC 协程池 UDP hashmap 网络编程自适应技术环形队列 Ring Buffer Circular Buffer InnoDB timewheel GroupCache Jaeger GOSSIP CAP Bash websocket 事务 GC TLS singleflight 闭包 Helm network iptables MITM HTTPS Tap Tun 路由 wireguard gvisor Git NAT 协议栈 Envoy FRP DPI gopacket Cgroup Namespace DNS eBPF GoZero Gost Clash gopsutil HIDS ELKEID XDP TC Linux Systemd netlink

FRIENDS

Apple Developer