PM2

引言

PM2 是管理和保持应用在线的守护进程管理器。

---

PM2功能

fork 模式 vs cluster 模式

• fork 模式
  单实例，可以修改exec_interpreter配置项，使用 pm2 运行 php、python 等其它语言的服务。
  pm2 默认使用 node，pm2 start app.js 等价于 require('child_process').spawn('node', ['server.js'])。
• cluster 模式
  多实例(仅限nodejs进程)，零配置实现各个实例之间的负载均衡。

watch 模式

当文件修改后，pm2 自动重启应用。

---

PM2原理

• 参考
  通过源码解析 Node.js 中 cluster 模块的主要功能实现
  pm2源码分析

待完善

---

常用命令

Fork mode

• pm2 start app.js --name my-api
  start and name process

Cluster mode

• pm2 start app.js -i 0|max
  Start maximum processes with LB depending on available CPUs
• pm2 scale app +3
  Scales app up by 3 workers
• pm2 scale app 2
  Scales app up or down to 2 workers total

Listing

• pm2 [list|ls|status]
  List the status of all application managed by PM2
• pm2 jlist
  Print process list in raw JSON
• pm2 prettylist
  Print process list in beautified JSON
• pm2 describe 0
  Display all informations about a specific process
• pm2 monit
  Terminal Based Dashboard

Logs

• pm2 logs [--raw]
  Display all processes logs in streaming
• pm2 logs --lines 200
  Dig in older logs
• pm2 flush
  Display all processes logs in streaming
• pm2 reloadLogs
  Reload all logs

Actions

• pm2 stop all|id
  Stop all processes or specific process id
• pm2 restart all|id
  Restart all processes or specific process id
• pm2 reload all|id
  Will 0s downtime reload (for NETWORKED apps)
• pm2 delete all|id
  Will remove all processes or specific process id from pm2 list

Misc

• pm2 reset all|id
  Reset meta data (restarted time...)
• pm2 updatePM2
  Update in memory pm2
• pm2 ping
  Ensure pm2 daemon has been launched
• pm2 sendSignal SIGUSR2 my-app
  Send system signal to script
• pm2 start app.js --no-daemon
• pm2 start app.js --no-vizion
• pm2 start app.js --no-autorestart