高性能Web服务器Nginx的配置与部署研究（14）平滑升级你的Nginx

1、概述（可以直接跳过看第2部分）

Nginx方便地帮助我们实现了平滑升级。其原理简单概括，就是：

（1）在不停掉老进程的情况下，启动新进程。

（2）老进程负责处理仍然没有处理完的请求，但不再接受处理请求。

（3）新进程接受新请求。

（4）老进程处理完所有请求，关闭所有连接后，停止。

这样就很方便地实现了平滑升级。一般有两种情况下需要升级Nginx，一种是确实要升级Nginx的版本，另一种是要为Nginx添加新的模块。

2. 升级过程

具体的操作也很简单，如下：

（0）查看当前版本

在存放Nginx的可执行文件的目录下输入：

./nginx -V 

./nginx -V

（1）下载新的Nginx版本并编译。

wget nginx-1.0.11.tar.gz  
tar zxvf nginx-1.0.11.tar.gz  
cd nginx-1.0.11  
./configure --add-module=/customized_module_0 --add-module=/customized_module_1  
make  

wget nginx-1.0.11.tar.gz tar zxvf nginx-1.0.11.tar.gz cd nginx-1.0.11 ./configure --add-module=/customized_module_0 --add-module=/customized_module_1 make
注意不要进行make install

（2）备份老版本的可执行文件

cd /usr/local/nginx/sbin  
sudo cp nginx nginx.old  

cd /usr/local/nginx/sbin sudo cp nginx nginx.old
（3）修改配置文件

如果有必要的话，进行配置文件的修改。

（4）拷贝新的可执行文件

sudo cp /home/michael/tmp/nginx-1.0.11/objs/nginx /usr/local/nginx/sbin/  

sudo cp /home/michael/tmp/nginx-1.0.11/objs/nginx /usr/local/nginx/sbin/

（5）升级

cd /home/michael/tmp/nginx-1.0.11  
make upgrade  

（6）清理多余文件

rm -rf /home/michael/tmp/nginx-1.0.11  

rm -rf /home/michael/tmp/nginx-1.0.11
（7）查看Nginx版本

cd /usr/local/nginx/sbin  
./nginx -V  

3、观察进程变化

在我的机器上可以观察到，我配置的是10个worker进程，启动后观察到：

root      6241 10419  0 10:51 ?        00:00:00 nginx: master process /usr/local/nginx/sbin/nginx  
nobody    6242  6241  2 10:51 ?        00:00:00 nginx: worker process        
nobody    6243  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6244  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6245  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6246  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6247  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6248  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6249  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6250  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6251  6241  1 10:51 ?        00:00:00 nginx: worker process        
nobody    6252  6241  0 10:51 ?        00:00:00 nginx: cache manager process  
nobody    6253  6241  0 10:51 ?        00:00:00 nginx: cache loader process  
luming    6310 25051  0 10:51 pts/1    00:00:00 grep --color=auto nginx  
nobody    7995 10419  0 Jan12 ?        00:20:37 nginx: worker process is shutting down  
nobody    7996 10419  0 Jan12 ?        00:20:11 nginx: worker process is shutting down  
nobody    7998 10419  0 Jan12 ?        00:20:04 nginx: worker process is shutting down  
nobody    8003 10419  0 Jan12 ?        00:20:12 nginx: worker process is shutting down  
root     10419     1  0 Jan08 ?        00:00:00 nginx: master process /usr/local/nginx/sbin/nginx  

root 6241 10419 0 10:51 ? 00:00:00 nginx: master process /usr/local/nginx/sbin/nginx nobody 6242 6241 2 10:51 ? 00:00:00 nginx: worker process nobody 6243 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6244 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6245 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6246 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6247 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6248 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6249 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6250 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6251 6241 1 10:51 ? 00:00:00 nginx: worker process nobody 6252 6241 0 10:51 ? 00:00:00 nginx: cache manager process nobody 6253 6241 0 10:51 ? 00:00:00 nginx: cache loader process luming 6310 25051 0 10:51 pts/1 00:00:00 grep --color=auto nginx nobody 7995 10419 0 Jan12 ? 00:20:37 nginx: worker process is shutting down nobody 7996 10419 0 Jan12 ? 00:20:11 nginx: worker process is shutting down nobody 7998 10419 0 Jan12 ? 00:20:04 nginx: worker process is shutting down nobody 8003 10419 0 Jan12 ? 00:20:12 nginx: worker process is shutting down root 10419 1 0 Jan08 ? 00:00:00 nginx: master process /usr/local/nginx/sbin/nginx
可见新的进程有1个master和10个worker，另外还有1个老的master（可以从时间上看出）和4个worker（其他6个老的worker已经处理完所有连接而shutdown了）。还有一个loader进程。过几秒种可以看到worker只有两个了：
root 6241 10419 0 10:51 ? 00:00:00 nginx: master process /usr/local/nginx/sbin/nginx nobody 6242 6241 1 10:51 ? 00:00:00 nginx: worker process nobody 6243 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6244 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6245 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6246 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6247 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6248 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6249 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6250 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6251 6241 0 10:51 ? 00:00:00 nginx: worker process nobody 6252 6241 0 10:51 ? 00:00:00 nginx: cache manager process nobody 6253 6241 0 10:51 ? 00:00:00 nginx: cache loader process luming 6430 25051 0 10:51 pts/1 00:00:00 grep --color=auto nginx nobody 7996 10419 0 Jan12 ? 00:20:11 nginx: worker process is shutting down nobody 8003 10419 0 Jan12 ? 00:20:12 nginx: worker process is shutting down root 10419 1 0 Jan08 ? 00:00:00 nginx: master process /usr/local/nginx/sbin/nginx

root      6241 10419  0 10:51 ?        00:00:00 nginx: master process /usr/local/nginx/sbin/nginx  
nobody    6242  6241  1 10:51 ?        00:00:00 nginx: worker process        
nobody    6243  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6244  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6245  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6246  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6247  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6248  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6249  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6250  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6251  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6252  6241  0 10:51 ?        00:00:00 nginx: cache manager process  
nobody    6253  6241  0 10:51 ?        00:00:00 nginx: cache loader process  
luming    6430 25051  0 10:51 pts/1    00:00:00 grep --color=auto nginx  
nobody    7996 10419  0 Jan12 ?        00:20:11 nginx: worker process is shutting down  
nobody    8003 10419  0 Jan12 ?        00:20:12 nginx: worker process is shutting down  
root     10419     1  0 Jan08 ?        00:00:00 nginx: master process /usr/local/nginx/sbin/nginx  

再过一小会儿观察：

root      6241     1  0 10:51 ?        00:00:00 nginx: master process /usr/local/nginx/sbin/nginx  
nobody    6242  6241  0 10:51 ?        00:00:01 nginx: worker process        
nobody    6243  6241  0 10:51 ?        00:00:01 nginx: worker process        
nobody    6244  6241  0 10:51 ?        00:00:01 nginx: worker process        
nobody    6245  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6246  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6247  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6248  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6249  6241  0 10:51 ?        00:00:00 nginx: worker process        
nobody    6250  6241  0 10:51 ?        00:00:01 nginx: worker process        
nobody    6251  6241  0 10:51 ?        00:00:02 nginx: worker process        
nobody    6252  6241  0 10:51 ?        00:00:00 nginx: cache manager process  
luming    8680 25051  0 10:56 pts/1    00:00:00 grep --color=auto nginx  

Congratulations! You can upgrade your Nginx server gracefully.