怎样重启Gunicorn

1. 寻找masterpid

通过执行如下命令，可以获取Gunicorn进程树：

pstree -ap|grep gunicorn

得到如下的结果。

|-grep,6194 --col gunicorn
  |   `-gunicorn,30080 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,4413 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,8030 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,8135 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,8137 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,11532 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,13460 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,19728 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,23585 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,23825 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,27921 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,28899 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,28900 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,28901 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,35637 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,36963 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,43074 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,43118 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,43232 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,43307 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,43308 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,44018 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,46996 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       |-gunicorn,47000 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py
  |       `-gunicorn,47650 /usr/local/bin/gunicorn collect:app -c collect_gunicorn.py

很显然，30080就是Gunicorn的主进程。

2. 重启Gunicorn任务

按照官方的推荐方法，很容易执行命令：

#   不需要sudo
kill -HUP 30080

执行上述命令后，再次执行“pstree -ap|grep gunicorn”，我们很容易发现，除了主进程，其他的Gunicorn进程都已经销毁，并新建了进程（进程ID发生了变化）。